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Introduction: Nanotechnology is promising for the development of new effective medicines. Silver nanoparticle preparations have been particularly well studied and a range of beneficial effects have been identified. Despite this, the sale of Colloidal silver (CS) preparations for therapeutic purposes has been banned by multiple regulatory authorities (including the FDA and TGA) on the basis of their perceived toxicity. This study evaluates the toxicity of electrolytically produced (CS) preparation, as well as some compounds used to produce CS by chemical synthesis. Materials and Methods: Toxicity of the CS preparation and the chemical toxins were evaluated using the Artemia nauplii toxicity assay. Additionally, the CS was tested for its protective effects against citrate and tannic acid-induced toxicity by screening combinations of CS and the toxins. Results: The CS preparation was nontoxic in the Artemia nauplii bioassay at all concentrations tested and did not induce mortality substantially above the seawater control at all concentrations ≤50 μg/mL. In contrast, citrate and tannic acid were strongly toxic, with LC50 values of 11.6 and 26.8 μg/mL respectively. Interestingly, co-incubation of varying concentrations of the CS preparation with 30 μg/mL of citrate resulted in protection against toxicity, with 50 μg/mL CS inhibiting ~65% of citrate-induced toxicity. In contrast, the CS preparation had no apparent effects on tannic acid-induced toxicity. Conclusion: The CS preparation tested in our study was nontoxic at all concentrations tested. Furthermore, the CS mitigated the toxic effects of citrate, but had no apparent effect on tannic acid-induced toxicity. Further studies are required to verify these findings in other toxicity models and to study the protective molecular mechanisms. [ABSTRACT FROM AUTHOR]

Background: Terminalia ferdinandiana Exell. is an endemic Australian plant with a high anti-oxidant capacity. Liquid solvent extractions of T. ferdinandiana leaves are strong inhibitors of the growth of numerous bacterial pathogens. Despite these promising therapeutic properties, methods for the rapid extraction of large quantities of T. ferdinandiana leaves are lacking. This study aimed to develop a rapid supercritical extraction method to produce extracts which retain therapeutic properties and phytochemistry characteristics. Materials and Methods: Terminalia ferdinandiana leaves were extracted by both solvent maceration extraction and Supercritical fluid extraction (SCE). The extracts were tested for the ability to inhibit bacterial growth using the disc diffusion assay. The antibacterial potency was further quantified using liquid dilution MIC assays. Toxicity was evaluated using an Artemia franciscana nauplii bioassay and GC-MS headspace analysis was used to evaluate phytochemical similarity between the extracts. Results: Terminalia ferdinandiana leaf SCE displayed strong bacterial growth inhibitory activity against bacterial triggers of autoimmune inflammatory diseases, with efficacies similar to the smaller laboratory scale methanolic liquid extractions. The growth inhibition of the ethyl acetate and methanolic solvent extracts and the SCE were particularly noteworthy against P. mirabilis (MICs = 128, 227 and 208μg/mL respectively) and A. baylyi (MICs = 452, 780 and 104 μg/mL respectively). GC-MS analysis of the berry SCE revealed similar terpenoid components and similar abundances to those in methanolic solvent leaf extraction. Furthermore, all liquid extracts and the SCE were non-toxic in the Artemia franciscana toxicity assay. Conclusion: The T. ferdinandiana SCE retained the tested therapeutic properties, was non-toxic and had similar phytochemical profiles as the smaller scale liquid solvent extractions. Thus, SCE is a viable method of rapidly extracting large masses of T. ferdinandiana leaves to produce quality extracts that retain therapeutic properties. [ABSTRACT FROM AUTHOR]

Introduction: An increase in antibiotic resistance and a corresponding decrease in antimicrobial discovery have directed researchers towards alternative therapies, including plant-based medicines. However, synergistic combinations of plant extracts with conventional antibiotics may be a far more effective approach in overcoming resistance and potentiating the activity of antibiotics that are otherwise ineffective against resistant bacterial strains. Materials and Methods: The antibacterial activity of Taraxacum officinale (L.) Weber ex F.H. Wigg root extracts was investigated by disc diffusion assays and quantified by liquid dilution and solid phase MIC assays. The extracts were also combined with a range of conventional antibiotics and tested against gastrointestinal disease-causing bacteria. The ΣFIC values obtained from these assays were used to determine the class of combinational effects. Toxicity was evaluated by Artemia nauplii mortality and HDF cytotoxicity assays. Results: Methanolic, aqueous and ethyl acetate T. officinale root extracts showed good inhibitory activity against several gastrointestinal bacterial pathogens. The methanolic were particularly good inhibitors of S. sonneii and S. newport, with MIC values in the range 400-450 μg/mL, whilst the ethyl acetate extract was the most potent inhibitor of S. newport growth (MIC=128 μg/mL). Of further interest, some combinations of the T. officinale root extracts and conventional antibiotics potentiated bacterial growth inhibition compared to the individual components. Five synergistic and two additive interactions were noted. Interestingly, only a single antagonistic interaction was evident, indicating that nearly all combinations could be used without decreasing the antibacterial activity of the components. All extracts were nontoxic in the ALA and HDF assays. Conclusion: Taraxacum officinale root extracts have potential as inhibitors of bacterial gastrointestinal pathogens. Furthermore, extract components may also potentiate the activity of some antibiotics that are relatively ineffective alone. Isolation and identification of these compounds may be beneficial in drug design against several gastrointestinal bacterial pathogens. [ABSTRACT FROM AUTHOR]

Background: Rubus idaeus L. leaves have been used in traditional healing systems for the treatment of morning sickness, easing labour pains and for preventing miscarriage. Whilst few studies have examined the leaves of this species for therapeutic properties, the fruit have antibacterial activity against multiple bacterial pathogens. This study examines the growth inhibitory effects of R. idaeus leaf extracts, both alone and in combination with conventional antibiotics against bacterial triggers of selected autoimmune inflammatory diseases. Results: Rubus idaeus leaf extracts displayed noteworthy antibacterial activity against several bacterial triggers of autoimmune diseases. The methanolic, aqueous and ethyl acetate extracts were particularly good inhibitors of P. mirabilis, A. baylyi and P. aeruginosa growth, with MIC values as low as 53 µg/mL. Combining the extracts with conventional antibiotics potentiated the inhibitory activity for several combinations containing chloramphenicol or gentamicin against A. baylyi. Interestingly, the other combinations were generally non-interactive and no antagonistic interactions were detected, indicating that all combinations can be used without decreasing the efficacy of the therapy. None of the individual components (or the combinations) were toxic in the ALA assay. Conclusion: Rubus idaeus leaf extracts have potential for the prevention and treatment of rheumatoid arthritis and multiple sclerosis when used alone. Furthermore, some combinations of the extracts and conventional antibiotics had greater potency against the bacterial triggers of multiple sclerosis, indicating they may be beneficial for prophylactic therapy in individuals genetically predisposed to that disease [ABSTRACT FROM AUTHOR]

The escalating global crisis of bacterial resistance to antibiotics poses a threat to public health. Urgent measures are required to identify novel antibacterial treatments. Multidrug-resistant bacterial strains limit the effective therapeutic options available, raising concerns about a post-antibiotic era and a reduced ability to treat infections that were previously not classified as serious. Simultaneously, the threat of emerging infectious diseases, including zoonotic pathogens, underscores the need to develop effective antibiotics against these pathogens. Innovative approaches to antibiotic development, such as novel chemical scaffolds, combination therapies, antimicrobial peptides, and phage therapy, show promise but require the discovery of new antibacterial compounds. Desert and rainforest ecosystems, despite being disparate in climate and biodiversity, offer unique prospects for developing antibacterial compounds. Deserts, which are characterized by extreme aridity and temperature fluctuations, harbor plants and micro-organisms with specialized antibacterial defences honed through evolution. Conversely, rainforests, with their biodiversity and high humidity, are promising for the development of potential antibacterial compounds. To date, much natural product research aimed at discovery of new antibiotic compounds has focussed on rainforest plants due to the biodiversity of these ecosystems, and because plants develop chemical defences against microbes that are prevalent in those environments. In comparison, the search for new antimicrobial compounds from desert plants has been overshadowed, despite some noteworthy antibacterial activities in arid environment plants. This commentary discusses the comparative potential of desert and rainforest ecosystems as reservoirs of novel antibacterial agents and emphasises the importance of screening plants in both environments. [ABSTRACT FROM AUTHOR]

According to the World Health Organisation (WHO), diarrhoea is the second leading cause of death in children under the age of five. It is a common symptom associated with gastrointestinal bacterial infections. Many antibiotics have lost their efficacy due to the rapid emergence of Antimicrobial Resistant (AMR) bacterial pathogens. Traditional Ayurvedic medicinal plants are likely to play a significant role in the development of new effective and safe therapies in the fight against AMR in gastrointestinal bacteria. Recent research has reported the effectiveness of numerous different Ayurvedic medicines in the treatment of gastrointestinal infections. One example is Triphala, which is a polyherbal formulation consisting of an equal mixture of dried fruit powders from the three Ayurvedic plants Terminalia bellirica (Gaertn.) Roxb., Terminalia chebula Retz. and Emblica officinalis Linn. This review discusses the principles of Ayurveda and summarises the traditional use of Ayurvedic plants in the treatment of diarrhoea, dysentery, and stomach discomfort. [ABSTRACT FROM AUTHOR]

Background: Tasmannia lanceolata berries and leaves have high antioxidant capacities and high levels of therapeutic phytochemicals. Despite this, the anticancer activity of T. lanceolata extracts has not been adequately explored. Materials and Methods: This study examined the anti-proliferative of T. lanceolata berry and leaf extracts against a panel of human carcinoma cell lines using MTS assays. The apoptotic activities were examined using cell imaging and caspase-3 activity assays. LC-MS and GC-MS headspace analysis were used to identify noteworthy phytochemical components. Results: The methanolic, aqueous and ethyl acetate extracts inhibited the proliferation of HeLa, Caco-2, Jeg-3, JAR, MC3T3-E1 and MG63 cell lines. The aqueous leaf extract was a particularly potent inhibitor of proliferation against most cell lines (HeLa IC50 = 230µg/mL; Caco-2 IC50 = 150µg/mL; Jeg-3 IC50 = 488µg/mL; JAR IC50 = 450µg/mL; MC3T3 IC50 = 195µg/mL; MG63 IC50 = 315µg/mL). The berry and leaf ethyl acetate extracts were also good inhibitors of proliferation of the same cell lines, albeit with slightly higher IC50 values. Morphological features consistent with apoptosis were evident in Caco-2 cells exposed to the berry and leaf ethyl acetate extracts, and the aqueous leaf extract. Furthermore, exposure of Caco-2 to sub-lethal concentrations of these extracts induced significantly elevated levels of caspase 3, indicating that the extracts induced apoptosis in Caco-2 cells. Conclusion: All T. lanceolata berry and leaf extracts induced apoptosis in a panel of cancer cells and were nontoxic in the ALA toxicity bioassay and in a HDF cell viability assay, supporting their potential as cancer chemotherapies. [ABSTRACT FROM AUTHOR]

Introduction: An increase in antibiotic resistance and a corresponding decrease in antimicrobial discovery have directed researchers towards alternative therapies, including plant based medicines. However, synergistic combinations of plant extracts with conventional antibiotics may be a far more effective approach in overcoming resistance and potentiating the activity of antibiotics that are otherwise ineffective against resistant bacterial strains. Materials and Methods: The antibacterial activity of Arctium lappa L. root extracts was investigated by disc diffusion and quantified by liquid dilution and solid phase MIC assays. The extracts were also combined with a range of conventional antibiotics and tested against various microbial triggers of autoimmune diseases. The ΣFIC values obtained from these assays were used to determine the class of combinational effects. Toxicity was evaluated by Artemia nauplii mortality and HDF cytotoxicity assays. Results: Methanolic and ethyl acetate A. lappa root extracts showed good inhibitory activity against several gastrointestinal bacterial pathogens. They were particularly good inhibitors of S. sonneii and B. cereus, with MIC values in the range 150-250μg/mL. The aqueous extract was also a noteworthy inhibitor of B. cereus growth. Of further interest, some combinations of the A. lappa root extracts and conventional antibiotics potentiated bacterial growth inhibition compared to the individual components. Four synergistic and five additive interactions were noted. Notably, no antagonistic interactions were evident, indicating that all combinations could be used without decreasing the antibacterial activity of the components. All extracts were non-toxic in the ALA and HDF assays. Conclusion: Arctium lappa root extracts have potential as inhibitors of bacterial gastrointestinal pathogens. Furthermore, extract components may also potentiate the activity of some antibiotics that are relatively ineffective alone. Isolation and identification of these compounds may be beneficial in drug design against several gastrointestinal bacterial pathogens. [ABSTRACT FROM AUTHOR]

The genus Eremophila (family Scrophulariaceae) consists of approximately 200 species that are widely distributed in the semi-arid and arid regions of Australia. Multiple Eremophila spp. are used as traditional medicines by the First Australians in the areas in which they grow. They are used for their antibacterial, antifungal, antiviral, antioxidant, anti-diabetic, anti-inflammatory, and cardiac properties. Many species of this genus are beneficial against several diseases and ailments. The antibacterial properties of the genus have been relatively well studied, with several important compounds identified and their mechanisms studied. In particular, Eremophila spp. are rich in terpenoids, and the antimicrobial bioactivities of many of these compounds have already been confirmed. The therapeutic properties of Eremophila spp. preparations and purified compounds have received substantially less attention, and much study is required to validate the traditional uses and to highlight species that warrant further investigation as drug leads. The aim of this study is to review and summarise the research into the medicinal properties, therapeutic mechanisms, and phytochemistry of Eremophila spp., with the aim of focussing future studies into the therapeutic potential of this important genus. [ABSTRACT FROM AUTHOR]

Introduction: Many high antioxidant fruit extracts can inhibit the growth of multiple bacterial pathogens. They may also inhibit the growth of malodour producing bacteria and thus be useful deodorant components, although this is yet to be tested for many Australian native fruits. Materials and Methods: Methanolic and aqueous K. pomifera and P. elatus fruit extracts were investigated by disc diffusion and liquid dilution MIC assays against the most significant bacterial contributors to axillary and plantar malodour. Toxicity was determined using Artemia franciscana nauplii bioassays and unbiased HPLC-MS QTOF analysis was used to identify interesting consituents of the most active extract. Results: Methanolic and aqueous K. pomifera and P. elatus fruit extracts displayed noteworthy bacterial growth inhibitory activity against all of the malodour forming bacteria tested. The methanolic K. pomifera extract had particularly good antibacterial effects, strongly inhibiting the growth of all bacteria, with MIC values substantially less than 1000 µg/mL. Indeed, liquid dilution (LD) MIC values of 610, 894, 663 and 625 µg/mL were recorded against C. jeikeium, P. acnes, B. linens and S. epidermidis respectively. Similar, albeit slightly higher LD MIC values were noted for the aqueous K. pomifera fruit extract, and for the methanolic and aqueous P. elatus fruit extracts against these bacteria. All K. pomifera and P. elatus fruit extracts were non-toxic in the Artemia fransiscana bioassay. Several interesting phytochemicals, including several tannins, were identified in the methanolic K. pomifera fruit extract. Conclusion: The lack of toxicity of the methanolic and aqueous K. pomifera and P. elatus fruit extracts and their noteworthy growth inhibition of axillary and plantar malodour producing bacteria indicate their potential as deodorant components. Further studies are warranted to isolate and identify the active components and to determine the antibacterial mechanism. [ABSTRACT FROM AUTHOR]

• One hundred and thirty eight plant species are recorded to treat eye disorders in traditional southern African medicine. • Pathogens associated with eye infections have been neglected. • Toxicity studies on many of the plant species are lacking. • No studies have focused on plant species to treat cataracts, glaucoma, macular degeneration, or diabetic retinopathy. • Sterility is a concern when administrating plant preparations directly into the eye. Ophthalmic infections are common and can cause substantial loss of eyesight. It is estimated that nearly 45% of the South African population has suffered from partial or total loss of eyesight with a substantial portion of this being due to infections. However, in approximately 80% of cases, this loss of eyesight could have been easily prevented or even treated. Multiple plant species are used in traditional South African medicine to treat eye infections, yet the therapeutic properties of most of these plants have been poorly studied. An extensive literature review of the ethnobotanical literature was undertaken to document the plant species used in southern African traditional medicine to treat eye disorders. A search was subsequently undertaken to identify and summarise studies that have provided some scientific evidence to support traditional use against these eye disorders. A total of 137 plant species belonging to 53 plant families are recorded to treat eye disorders in traditional southern African medicine. The use of many plants was credited with vague indications such as "eye problems" and "eye conditions". Only 42 of the identified species have been evaluated for inhibitory activity against any eye-related pathogens. Whilst bacterial Staphylococcal pathogens were the most extensively tested, many other pathogens associated with eye infections have been neglected. Additionally, several fungal and most viral pathogens have been completely neglected to date. Furthermore, few studies have tested the toxicity of the plant extracts and mechanistic studies are lacking. Whilst this review identifies and highlights plant species used in traditional southern African medicine to treat eye infections, substantially more research is required to completely validate their traditional use and to evaluate the potential of the plant preparations as drug leads. [ABSTRACT FROM AUTHOR]

Introduction: Acne vulgaris is a skin conditions that affects most adolescents and may also afflict adults. Medicinal plant extracts may provide leads for the development of new topical and/or oral therapies for acnes vulgaris, yet many traditional medicine plants are yet to be screened for growth inhibitory activity against Cutibacterium acnes (the major bacterial cause of acne). Materials and Methods: Methanolic and aqueous Scaevola spinescens R.Br. leaf extracts were investigated by disc diffusion and liquid dilution MIC assays against Cutibacterium acnes (a significant bacterial cause of acne). Toxicity was determined using Artemia franciscana nauplii bioassays. Results: Methanolic and aqueous S. spinescens leaf extracts displayed noteworthy bacterial growth inhibitory activity against C. acnes growth. The aqueous S. spinescens leaf extract had particularly good antibacterial effects against C. acnes, with an LD MIC value of 344 μg/mL. Similar, albeit slightly higher LD MIC values were noted for the aqueous methanolic S. spinescens leaf extract against C. acnes (LD MIC = 875 μg/mL). The methanolic and aqueous S. spinescens leaf extracts were nontoxic in the Artemia fransiscana bioassay, with LC50 values substantially >1000 μg/mL. Conclusion: The lack of toxicity of the methanolic and aqueous S. spinescens leaf extracts and their noteworthy growth inhibition of C. acnes indicate their potential as treatments to alleviate acne vulgaris. Further studies are warranted to isolate and identify the active components and to determine their antibacterial mechanism. [ABSTRACT FROM AUTHOR]

Traditional medicines prepared using Terminalia species have been used globally to treat inflammation and pathogenic infections. Recent studies have demonstrated that multiple Asian and African Terminalia spp. inhibit bacterial triggers of some autoimmune inflammatory diseases, including ankylosing spondylitis. Despite this, the effects of Australian Terminalia spp. on a bacterial trigger of ankylosing spondylitis (K. pneumoniae) remain unexplored. Fifty-five extracts from five Australian Terminalia spp. were investigated for K. pneumoniae growth inhibitory activity. Methanolic, aqueous and ethyl acetate extracts of most species and plant parts inhibited K. pneumoniae growth, with varying potencies. Methanolic leaf extracts were generally the most potent bacterial growth inhibitors, with minimum inhibitory concentration (MIC) values of 66 μg/mL (T. ferdinandiana), 128 μg/mL (T. carpenteriae) and 83 μg/mL (T. petiolares). However, the aqueous leaf extract was the most potent T. grandiflora extract (MIC = 87 μg/mL). All T. catappa extracts displayed low growth inhibitory activity. The Terminalia spp. methanolic leaf extracts were examined by liquid chromatography-mass spectrometry (LC–MS) and gas chromatography-mass spectrometry (GC–MS). All contained a relative abundance of simple gallotannins (particularly gallic and chebulic acids), the flavonoid luteolin, as well as the monoterpenoids cineole and terpineol. Notably, all Terminalia spp. were non-toxic or of low toxicity in ALA and HDF toxicity assays, highlighting their potential for preventing the onset of ankylosing spondylitis and treating its symptoms once the disease is established, although this needs to be verified in in vivo systems. [ABSTRACT FROM AUTHOR]

Background: Antibiotic drugs have been widely applied in the treatment of bacterial infections. However, with the overuse and unreasonable adoption of antibiotics, a variety of bacteria have developed resistance to commonly used antibiotics. Bacterial pathogens with multi-drug resistance mechanisms have made many infectious diseases more difficult to be treat and new therapies are urgently needed. Methods: An extensive review of ethnobotanical books, reviews and primary scientific studies was undertaken to identify TCMs used to treat bacterial infections and the individual components of those medicines this information was used to identify gaps in the current research that require further study. Results: Traditional Chinese medicine contain multiple components and function via multiple pathways against multiple targets. Many of these pathways and concepts may be difficult for non-Chinese due to their complexities. However, an evaluation of TCMs for antibacterial activities is an attractive option for antibiotic discovery and development as they generally have low toxicity, low side effects and as combinational therapies, there is no inherent drug resistances in human bacterial pathogens towards these drugs. This study reviews the current status of bacterial resistance, the mechanism of traditional Chinese medicine against bacterial infections, and the adoption progress of Chinese herbal medicines in the treatment of resistant bacterial infections. Conclusion: TCM can inhibit the growth of bacterial pathogens and can participate in mediating the immune function of multiple bodily aspects. Therefore, Chinese herbal medicine may provide new leads to treat drug-resistant bacterial infections. [ABSTRACT FROM AUTHOR]

Introduction: Terminalia arjuna (Roxb.) Wight and Arn. is a southern Asian plant commonly used in Ayurveda to treat multiple conditions, including for the treatment of inflammation, and as a general antimicrobial agent. Despite this, few studies have tested this species for the ability to block the growth of bacterial triggers of some autoimmune inflammatory diseases. Furthermore, the ability of T. arjuna to potentiate the activity of conventional antibiotics is yet to be investigated. Materials and Methods: The minimum inhibitory concentration of the extracts and extract-antibiotic combinations was determined by disc diffusion and liquid dilution MIC methods. Fractional inhibitory concentration values were calculated to evaluate the combinational effect of combinations of extracts and conventional antibiotics. When synergistic interactions were detected, isobologram analysis was used to determine the ideal ratios for synergy. Toxicity was evaluated by Artemia nauplii mortality and HDF cell viability assays. Results: Methanolc, aqueous and ethyl acetate T. arjuna extracts were good inhibitors of P. mirabilis and K. pneumoniae growth when tested alone. The methanolic and aqueous extracts also synergised the inhibitory activity of ciprofloxacin against P. mirabilis and K. pneumoniae when used in combination. Additionally, numerous additive combinational effects were noted. T. arjuna chloroform extract was also a moderate inhibitor of a multi-drug resistant P. aeruginosa strain when tested alone, but did not potentiate the activity of any of the conventional antibiotics tested. All extracts and extract-antibiotic combinations were nontoxic in the Artemia nauplii mortality and HDF proliferation assays, indicating their suitability for therapeutic use. Conclusion: T. arjuna extracts have potential as inhibitors of bacterial triggers of selected autoimmune inflammatory diseases. Furthermore, T. arjuna extracts potentiate the activity of ciprofloxacin against P. mirabilis and K. pneumoniae and therefore may be beneficial in drug design against these bacteria. [ABSTRACT FROM AUTHOR]

Introduction: The development of bacterial strains that are resistant to multiple antibiotics has made the discovery of new antibiotics a priority for medical research. Examination of plants for new antimicrobial agents is an attractive prospect and numerous recent studies have screened plants for antibacterial activity. Despite this, Australian native plants have been relatively neglected. Heritiera actinophyllum (F.M.Bailey) Kosterm. is a rainforest tree that is native to eastern coastal regions of Australia. Material from this species has not yet been examined for antibacterial properties against human pathogens. Materials and Methods: The ability of H. actinophyllum leaf extracts to inhibit the growth of a panel of bacterial pathogens was investigated by disc diffusion assay. Toxicity was examined using the Artemia franciscana nauplii bioassay. Results: H. actinophyllum methanolic and aqueous extracts were ineffective at inhibiting the growth of gram-positive and gram-negative panels of bacteria. The extracts were non-toxic or of low toxicity following 24 h exposure. Conclusion: The H. actinophyllum leaf extracts lacked growth inhibitory bioactivity against a panel of pathogenic bacteria and were nontoxic in the Artemia nauplii assay. However, these extracts may have other therapeutic properties and testing against protozoa, fungi, and virus and tumour cells is required. [ABSTRACT FROM AUTHOR]

Introduction: The development of bacterial strains that are resistant to multiple antibiotics has made the discovery of new antibiotics a priority for medical research. Examination of plants for new antimicrobial agents is an attractive prospect and numerous recent studies have screened plants for antibacterial activity. Despite this, Australian native plants have been relatively neglected. Mirbelia oxylobioides F. Muell. is a native Australian shrub of the family Fabaceae. Very few studies have yet examined species for antibacterial properties against human pathogens. Methods: The ability of M. oxyloboides leaf extracts to inhibit the growth of a panel of bacterial pathogens was investigated by disc diffusion assay. Toxicity was examined using the Artemia franciscana nauplii bioassay. Results: M. oxyloboides methanolic and aqueous extracts were ineffective at inhibiting the growth of gram-positive and gram-negative panels of bacteria. The extracts were non-toxic or of low toxicity following 24 h exposure. Conclusion: The M. oxyloboides leaf extracts lacked growth inhibitory bioactivity against a panel of pathogenic bacteria and were non-toxic in the Artemia nauplii assay. However, these extracts may have other therapeutic properties and testing against protozoa, fungi, virus and tumour cells is required. [ABSTRACT FROM AUTHOR]

Introduction: Kunzea ambigua (Sm.) Druce and Kunzea flavescens C.T. White and W.D. Francis are endemic Australian plants. Decoctions, infusions and essential oils produced from the leaves were used traditionally to treat a variety of bacterial diseases. Despite this, these species have not been rigorously examined for antibacterial properties against many pathogens. Methods: The antimicrobial activity of K. ambigua and K. flavescens essential oils and a K. ambigua hydrosol was investigated by disc diffusion and liquid dilution MIC assays against a panel of pathogenic bacteria. Toxicity was determined using the Artemia franciscana nauplii bioassay. Results: K. ambigua and K. flavescens essential oils displayed noteworthy growth inhibitory activity against A. baylyi, K. pneumonia, P. mirabilis and P. aeruginosa (MIC values substantially <1000μg/mL). Indeed, MIC values as low as 33μg/mL were noted against P. aeruginosa. Noteworthy growth inhibitory activity was also noted for the K. ambigua hydrosol against A. baylyi and P. aeruginosa. All extracts were determined to be non-toxic in the Artemia franciscana nauplii bioassay, indicating their safety for internal use as well as for topical uses. Conclusion: The lack of toxicity of the Kunzea spp. extracts and their growth inhibitory bioactivity against a panel of pathogenic bacteria partially validate the traditional usage of these species to treat bacterial diseases and indicate their potential in the development of antiseptic agents. [ABSTRACT FROM AUTHOR]

Introduction: The development of antibiotic resistant bacteria has resulted in treatment failure for the current antibiotic regimen against many bacteria. A corresponding decrease in the development of new antibiotic therapies has highlighted the urgent need for the discovery of new antibiotics. An examination of 'superfoods' is an attractive option due to the high antioxidant capacities and beneficial secondary compounds reported in many 'superfoods'. This study was undertaken to test kale and spirulina extracts for the ability to inhibit the growth of a panel of bacterial pathogens of human importance. Methods: Commercially sourced kale and spirulina powders were extracted and tested for antimicrobial activity using modified disc diffusion and liquid dilution MIC methods. Toxicity was evaluated using an Artemia franciscana nauplii bioassay. Results: The methanolic and aqueous extracts of kale and spirulina displayed noteworthy growth inhibitory activity against P. mirabilis. The aqueous spirulina extract was a particularly good inhibitor of P. mirabilis, with MIC values as low as 220µg/mL. In contrast, all extracts were ineffective or of low inhibitory activity against all other bacteria tested. All extracts were non-toxic in the Artemia nauplii bioassay, confirming their suitability as natural antibacterial therapies. Conclusion: These studies indicate that aqueous kale and spirulina extracts are promising inhibitors of P. mirabilis growth and may be useful in the prevention and treatment of rheumatoid arthritis, as well as other diseases caused by that bacterium. [ABSTRACT FROM AUTHOR]

The First Australians had well-developed healing systems. Groote Eylandt inhabitants used a variety of plant species to treat diarrhoea and other gastrointestinal illnesses. This study was undertaken to test, identify, and evaluate traditional medicines to treat these conditions against gastrointestinal bacterial, protozoal, and viral pathogens, as well as against cancer cell proliferation. Six plant species (Buchanania obovata Engl., Casuarina equisetifolia L., Eucalyptus tetrodonta F. Muell., Planchonia careya (F. Muell.) R. Knuth, Terminalia carpentariae C. T. White, and Vigna vexillata (L.) A. Rich.) were selected from a survey of a panel of elders from the Warnindhilyagwa tribe and compared with the published literature. Decoctions prepared according to traditional methods were screened for growth inhibitory activity of a panel of diarrhoea-causing bacterial pathogens by disc diffusion and liquid dilution MIC assays. Inhibitory activity against the gastrointestinal protozoal parasite Giardia duodenalis and antiproliferative activity against human colorectal (Caco2) and cervical (HeLa) cancer cell lines were evaluated using MTS-based colorimetric cell proliferation assays. Preliminary antiviral screening was accomplished using an MS2 bacteriophage plaque reduction assay. Toxicity was evaluated using Artemia franciscana nauplii mortality and HDF cell viability bioassays. All traditional medicines tested inhibited bacterial growth, often with MIC values substantially <1000 μg/mL. T. carpentariae was particularly noteworthy, with MIC values of 230–350 μg/mL against Citrobacter freundii, Salmonella newport, Shigella sonnei, Staphylococcus aureus, and Staphylococcus epidermidis. This species also had MICs 450–950 μg/mL against all other bacterial pathogens. B. obovata Engl. and E. tetrodonta were also good inhibitors of bacterial growth, albeit with substantially higher MIC values than determined for T. carpentariae. The T. carpentariae decoction was also the best inhibitor of MS2 phage replication (IC50 = 427 μg/mL) and Caco2 and HeLa proliferation (IC50 values of 885 and 85 μg/mL, respectively). None of the extracts were particularly strong inhibitors of Giardia duodenalis growth. All decoctions were nontoxic in the Artemia nauplii and HDF cell viability bioassays, indicating their suitability for therapeutic use. [ABSTRACT FROM AUTHOR]

Introduction: Trachyspermum ammi leaves and seeds have been used as dietary supplements and to treat multiple pathogenic diseases in several traditional healing systems. Despite this, their therapeutic properties have been poorly studied. Methods: Chloroform, ethyl acetate, hexane, methanol and water extracts of T. ammi were prepared and tested and the activity was compared to that of standard antibiotics for their in vitro antibacterial activity against ten human bacterial pathogens. The antibacterial activity was studied by standard disc diffusion assays and the activity was recorded as zones of inhibition. Results: All T. ammi seed extracts were ineffective at inhibiting the growth of all of the gram-positive and gram-negative bacteria pathogens screened against. Conclusion: Despite their use in traditional healing systems to treat some pathogenic diseases, T. ammi seed extracts were completely ineffective bacterial growth inhibitors. However, these extracts were screened against a limited panel of bacteria and further testing against other pathogens is required. [ABSTRACT FROM AUTHOR]

Introduction: Tabebuia impetiginosa (Mart. Ex DC. Mattos) bark has been used to treat inflammation and cancer, as well as a variety of pathogenic diseases, in traditional South American healing systems. As practitioners of complementary medicine frequently use herbal medicines concurrently with conventional antibiotics, the effects of both therapies in combination needs to be evaluated. Methods: The growth inhibitory activity of T. impetiginosa bark extracts was assessed against a panel of gastrointestinal bacterial pathogens by standard disc diffusion and liquid dilution minimum inhibitory concentration (MIC) methods. Combinational effects between the extracts and conventional antimicrobials were classified using the sum of the fractional inhibitory concentration. The toxicity of the individual samples and combinations was evaluated by Artemia lethality and MTS HDF cell viability assays. Results: T. impetiginosa bark extracts strongly inhibited the growth of B. cereus but were ineffective against Escherichia coli, Shigella sonnei, Staphylococcus aureus. The mid polarity ethyl acetate extract was a particularly good inhibitor of B. cereus growth (DD and LD MIC values of 45 and 245 µg/mL respectively). However, the effects of combinations of the extracts and conventional antibiotics was of considerably more interest. Although no synergistic interactions were noted, the potency of some combinations were substantially potentiated compared to activity of the individual components. Additive potentiation was was noted for combinations containing the T. impetiginosa water extract and erythromycin, chloramphenicol or penicillin-G against E. coli and S. aureus. Combinations containing ciprofloxacin also produced additive effects against all of the bacteria tested. Therefore, these combinations have enhanced benefits over either component alone. Of further note, antagonistic interactions were also detected in several combinations containing ciprofloxacin (particularly against S. aureus). These combinations should therefore be avoided against that bacterium. Conclusion: T. impetiginosa bark extracts inhibit the growth of B. cereus when tested alone and potentiated the activity of some conventional antibiotics against a panel of gastrointestinal pathogens when used in combination. Thus, T. impetiginosa bark extracts have potential in the treatment of diarrhoea and other gastrointestinal diseases. [ABSTRACT FROM AUTHOR]

Introduction: Alphitonia excelsa (Fenzl) Benth. is a large tree that is native to the east coast and northern regions of Australia. Decoctions and infusions produced from the leaves were used by the first Australians to treat a variety of bacterial diseases. Despite this, A. excelsa leaf extractions have not been rigorously examined for antibacterial properties against many pathogens. Methods: The antimicrobial activity of A. excelsa leaf extractions was investigated by disc diffusion and growth time course assays against a panel of pathogenic bacteria. The growth inhibitory activity was quantified by MIC determination. Toxicity was determined using the Artemia franciscana nauplii bioassay. Results: Polar to mid-polarity A. excelsa leaf solvent extractions inhibited the growth of a wide range of bacterial species. Growth of both gram positive and gram negative bacteria was inhibited by the A. excelsa leaf extracts to approximately the same extent. The methanolic extracts were the most potent growth inhibitor against all bacteria tested. The methanolic, aqueous and ethyl acetate A. excelsa leaf extracts were particularly potent inhibitors of P. mirabilis growth, with MIC values as low as 118µg/mL for the methanolic extract. A. hydrophilia, E. coli, K. pneumonia, S. marcenscens and B. cereus were also particularly susceptible to the methanolic extract, with MIC values generally substantially <1000 µg/mL. The antibacterial activity of the methanolic A. excelsa leaf extract was further investigated by growth time course assays which showed significant growth inhibition in cultures of P. mirabilis and B. cereus within 1 h of exposure. All extracts were determined to be nontoxic in the Artemia franciscana nauplii bioassay, indicating their safety for internal use as well as for topical uses. Conclusion: The lack of toxicity of the A. excelsa leaf extracts and their growth inhibitory bioactivity against a panel of pathogenic bacteria partially validate the traditional usage of this species to treat bacterial diseases and indicate their potential in the development of antiseptic agents. [ABSTRACT FROM AUTHOR]

Introduction: Brachychiton acerifolius (A.Cunn. ex G.Don) Macarthur and C. moore is a large tree that is native to subtropical regions of the east of Australia. Decoctions and infusions produced from the leaves of the related species Brachychiton diversifolius were used by the first Australians to treat a variety of bacterial diseases. Despite this, B. acerifolius leaf and flower extracts have not been rigorously examined for antibacterial properties against many pathogens. Methods: The antimicrobial activity of B. acerifolius leaf and flower extracts was investigated by disc diffusion and growth time course assays against a panel of pathogenic bacteria. The growth inhibitory activity was quantified by MIC determination. Toxicity was determined using the Artemia franciscana nauplii bioassay. Results: Methanolic B. acerifolius leaf and flower extracts inhibited the growth of a wide range of bacterial species. Growth of both gram positive and gramnegative bacteria was inhibited by the B. acerifolius leaf and flower extracts, although the gram negative bacteria were substantially more susceptible to the extracts than the gram positive bacteria were. The leaf extracts were more potent growth inhibitors than the flower extracts against all bacteria tested. The B. acerifolius leaf extract was a strong inhibitor of A. faecalis, K. pneumonia, P. fluorescens, S. newport, S. sonnei, B. cereus, S. aureus and S. pyogenes growth, with MIC values substantially <1000µg/mL. The antibacterial activity of the methanolic B. acerifolius leaf extract was further investigated by growth time course assays which showed significant growth inhibition in cultures of P. fluorsecens and B. cereus within 1hr of exposure. Both extracts were determined to be nontoxic in the Artemia franciscana nauplii bioassay, indicating their safety for internal use as well as for topical uses. Conclusion: The lack of toxicity of the B. acerifolius leaf and flower extracts and their growth inhibitory bioactivity against a panel of pathogenic bacteria partially validate the traditional usage of this species to treat bacterial diseases and indicates their potential in the development of antiseptic agents. [ABSTRACT FROM AUTHOR]

Introduction: The development of multi-antibiotic resistant strains of bacteria has necessitated the search for new, effective antibacterial therapies. B. collina and B. oblongifolia leaves were used by Australian Aborigines to treat bacterial infections. However, little research has been published on antibacterial activity of these species. Methods: The ability of B. collina and B. oblongifolia leaf extracts to inhibit the growth of gram-negative and gram-positive bacterial species was investigated by disc diffusion and growth time course assays. The growth inhibitory activity was further quantified by MIC determination. Toxicity was determined using the Artemia franciscana nauplii bioassay. Results: The B. collina and B. oblongifolia leaf extracts were good inhibitors of the growth of both gram-positive and gram-negative bacteria. The B. collina and B. oblongifolia leaf extracts were particularly good inhibitors of A. faecalis growth (MICs of 225 and 486µg/mL respectively) and B. cereus growth (MICs of 515 and 875µg/mL respectively). The B. collina extract was also a good inhibitor of B. subtilis growth, whilst the B. oblongifolia extract was a moderate growth inhibitor (MIC values of 923 and 1250µg/mL respectively). A similar, trend was noted for Y. entercolitica growth inhition (MICs of 518 and 1136µg/mL respectively). Whilst MIC values were also determined against other bacterial species, they generally indicated low-moderate activity. The B. collina and B. oblongifolia leaf extracts were further investigated by growth time course assays against A. faecalis and B. cereus. Interestingly, both extracts showed significant growth inhibition within 1h of exposure against both bacterial species. All extracts were determined to be nontoxic in the Artemia franciscana nauplii bioassay, indicating their safety for the treatment of bacterial infections. Conclusion: The lack of toxicity of the B. collina and B. oblongifolia leaf extracts and their growth inhibitory bioactivity against multiple bacterial species indicate their potential in the development of new antibiotic chemotherapies. [ABSTRACT FROM AUTHOR]

Introduction: Podocarpus latifolius (Thunb.) R.Br. ex Mirb. is a large tree that is native to southern Africa. This species has been used extensively for multiple therapeutic purposes across the southern part of the African continent. Despite this, P. latifolius leaf extracts have not been rigorously examined growth inhibitory properties against many bacteria, including the bacterial triggers of autoimmune inflammatory diseases. Materials and Methods: The antimicrobial activity of P. latifolia leaf solvent extractions was investigated by disc diffusion and growth time course assays against some bacterial triggers of rheumatoid arthritis and ankylosing spondylitis. The growth inhibitory activity was further quantified by MIC determination. Toxicity was determined using the Artemia franciscana nauplii bioassay. Results: Methanolic and aqueous P. latifolia leaf extracts were good inhibitors of P. mirabilis and K. pneumoniae. The inhibitory activity of both extracts was particularly noteworthy against the bacterial trigger of ankylosing spondylitis (K. pneumonia), with MICs of 343 and 557 µg/mL determined for the methanolic and aqueous extracts respectively. The extracts also displayed noteworthy activity against a bacterial trigger of rheumatoid arthritis (P. mirabilis), with MICs of 580 and 634 µg/mL respectively. The antibacterial activity of the methanolic and aqueous P. latifolia leaf extracts were further investigated by growth time course assays, which showed significant growth inhibition in cultures of P. mirabilis and K. pneumoniae within 1 hr of exposure. The extracts were determined to be nontoxic in the Artemia franciscana nauplii bioassay, indicating their safety for prophylactic use in preventing these autoimmune inflammatory diseases. Conclusion: The lack of toxicity of the P. latifolia leaf extracts and their growth inhibitory bioactivity against the bacterial triggers of rheumatoid arthritis and ankylosing spondylitis indicate their potential in the development of new therapies targeting the onset of these diseases. [ABSTRACT FROM AUTHOR]

Terminalia canescens DC. Radlk. (family: Combretaceae) is native to northern Australia. Species of the genus Terminalia are widely used as traditional medicines to treat diverse ailments, including bacterial infections. However, we were unable to find any studies that had examined the antimicrobial activity of T. canescens. In this study, T. canescens was screened against a panel of bacterial pathogens, including multi-antibiotic-resistant strains. Solvents with different polarities were used to extract different complements of phytochemicals from T. canescens leaves. Methanolic and aqueous extracts exhibited substantial antimicrobial activity against various pathogens, including those that are multidrug-resistant strains. When combined with some selected clinical antibiotics, some extracts potentiated the antibacterial inhibitory activity. This study identified two synergistic, eleven additive, eleven non-interactive and eight antagonistic interactions. The toxicities of the plant extracts were examined in the Artemia franciscana nauplii assay and were found to be non-toxic, except the aqueous extract, which showed toxicity. Metabolomic liquid chromatography–mass spectrometry (LC-MS) analyses highlighted and identified several flavonoids, including vitexin, quercetin, orientin and kaempferol, as well as the tannins ellagic acid and pyrogallol, which may contribute to the antibacterial activities observed herein. The possible mechanism of action of these extracts was further explored in this study. [ABSTRACT FROM AUTHOR]

Introduction: The development of multi-antibiotic resistant strains of bacteria has necessitated the search for new effective antibacterial therapies. Several Grevillea spp. were used traditionally to treat pathogenic illness and are rich in phytocompounds with antibacterial activity. Despite this, the antibacterial activity of Australian Grevillea spp. extracts have not been extensively examined. Methods: The ability of G. juncifolia and G. robusta leaf and flower extracts to inhibit the growth of gram-negative and gram-positive bacterial species and some fungi was investigated by disc diffusion assays. The growth inhibitory activity was further quantified by MIC determination. Toxicity was determined using the Artemia franciscana nauplii bioassay. Results: The G. juncifolia and G. robusta extracts were good inhibitors of the growth of both gram-positive and gram-negative bacteria yet were completely ineffective against all fungal species tested. The leaf extracts generally had better antibacterial activity than the flower extracts. The G. juncifolia leaf extract was a particularly good inhibitor of A. faecalis, P. fluorescens, Y. entercolitica and B. subtilis growth, with MIC values of 62, 533, 736 and 682µg/mL respectively. The G. robusta leaf extract was a potent inhibitor of B. cereus and B. subtilis growth (145 and 83µg/mL respectively). That extract was also a good inhibitor of A. faecalis, P. fluorescens, S. salford, S. aureus and S. epidermidis growth, albeit with substantially higher MIC values. In contrast, none of the extracts inhibited fungal growth. All extracts were determined to be non-toxic in the Artemia franciscana nauplii bioassay, indicating their safety for the treatment of bacterial infections. Conclusion: The lack of toxicity of the G. juncifolia and G. robusta extracts and their growth inhibitory bioactivity against grampositive and gram-negative bacteria indicate their potential in the development of new antibiotic chemotherapies. [ABSTRACT FROM AUTHOR]

Introduction: An increase in antibiotic resistance and a corresponding decrease in antimicrobial discovery have directed researchers towards alternative therapies, including plant-based medicines. However, synergistic combinations of plant extracts with conventional antibiotics are a far more effective approach in overcoming resistance and potentiating the activity of antibiotics that are otherwise ineffective against resistant bacterial strains. Methods: In this study, Petalostigma spp. (native Australian medicinal plants) extracts were combined with a range of conventional antibiotics and tested against various microbial triggers of autoimmune diseases. The fruit and leaves were extracted separately with solvents of varying polarity and investigated for the ability to inhibit bacterial growth using disc diffusion and liquid dilution MIC techniques. Results: The methanolic and water extracts showed low to moderate inhibitory activity against several microbes. However, combinations of the mid-low polarity extracts with conventional antibiotics proved significantly more effective in inhibiting the growth of Proteus mirabilis and Acinetobacter baylyi (bacterial triggers of rheumatoid arthritis and multiple sclerosis respectively). In total, 14 different combinations proved to be synergistic. Notably, two antibiotics (chloramphenicol and erythromycin) with no inhibitory activity against P. mirabilis alone were shown to have substantial activity when tested in combination with Petalostigma spp. extracts. Conclusion: Although the mechanisms of synergy are still unclear, studies indicate that compounds within Petalostigma spp. may mimic the actions of resistance modifying agents, thus potentiating the activity of several antibiotics that are relatively ineffective alone. Isolation of these agents may be highly beneficial in drug design against several bacteria including the microbial triggers of rheumatoid arthritis and multiple sclerosis. [ABSTRACT FROM AUTHOR]

Background: Buchanania obovata is an endemic Australian plant that has been used traditionally to treat a variety of bacterial, fungal and protozoal pathogenic diseases. This study was undertaken to test B. obovata fruit extracts for the ability to inhibit microbial and cancer cell growth. Materials and Methods: B. obovata fruit powder was extracted and tested for antimicrobial activity using disc diffusion and MIC methods. Inhibitory activity against the gastrointestinal protozoal parasite Giardia duodenalis and antiproliferative activity against human colorectal (Caco2) and cervical (HeLa) cancer cell lines was evaluated using MTS-based colorimetric assays. Toxicity was evaluated using an Artemia franciscana nauplii bioassay. Results: The methanol, water and ethyl acetate B. obovata fruit extracts displayed potent antibacterial activity. The methanol and water extracts displayed the broadest specificity, inhibiting the growth of all of the Gram positive and Gram negative bacterial species tested. The ethyl acetate extract also displayed antibacterial activity, inhibiting the growth of 7 (88%) of the Gram negative and 2 (50%) of the Gram positive bacterial species. The methanol extract also displayed broad spectrum antifungal activity, inhibiting the growth of all 3 fungal species, including an ampicillin resistant strain of A. niger. The water extract also inhibited the growth of 2 (66%) of the fungal species tested. None of the extracts were particularly good inhibitors of the growth of the gastrointestinal parasite Giardia duodenalis. The methanolic and aqueous extracts were effective at blocking the proliferation of the colorectal cancer cell line Caco2 to between approximately 20 and 30% of the untreated cell growth. All extracts also inhibited HeLa cervical cancer cell growth. The methanol, water and ethyl acetate extracts displayed substantial toxicity in the Artemia nauplii assay. Conclusion: This study shows that B. obovata fruit extracts inhibit bacteria and fungi, but are relatively ineffective against G. duodenalis. The extracts were also effective inhibitors of Caco2 and HeLa cell proliferation, indicating that the extracts have potential in the treatment of microbial diseases and some cancers. [ABSTRACT FROM AUTHOR]

Terminalia chebula Retz. is a northern Indian plant species known for its anti-inflammatory and antimicrobial properties. T. chebula fruit powder was extracted with solvents of varying polarity and screened for bacterial growth inhibition by disc diffusion assay. The minimum inhibitory concentration (MIC) was quantified by both liquid dilution and disc diffusion techniques. To screen for combinatorial effects, the T. chebula fruit extracts were combined with a range of conventional antibiotics and tested against each bacteria using a liquid dilution assay. Where synergy was detected, the optimal ratios were determined using isobologram analysis. Toxicity was examined using Artemia nauplii and HDF bioassays. T. chebula fruit methanolic, aqueous and ethyl acetate extracts displayed strong antimicrobial activity against the bacterial triggers of all autoimmune inflammatory diseases except K. pneumoniae, for which only moderate inhibition was observed. Indeed, MIC values as low as 195 μg/mL were measured for the aqueous extract against a resistant strain of P. aeruginosa. Of further note, both the aqueous and ethyl acetate extracts interacted synergistically in combination with tetracycline against K. pneumoniae (Σ FIC 0.38 and 0.25 respectively). All extracts were nontoxic in the Artemia and HDF toxicity assays, further indicating their potential for medicinal use. [ABSTRACT FROM AUTHOR]

Background: The aim of this project was to investigate the efficacy of Astragalus membranaceus (Astragalus) extracts, alone and in combination with conventional antibiotics, against diarrhoea- and dysentery-causing pathogens, as well as against non-pathogenic gastrointestinal bacterial strains. The study sought to validate the chemotherapeutic potential of a traditional Chinese medicinal plant and to identify combinational therapies with increased efficacy compared to either the extracts or conventional antibiotics alone. Methods: Astragalus root powder was extracted with solvents of varying polarity and screened for inhibition of bacterial growth. Susceptibility was assessed by disc diffusion techniques, whilst the minimum inhibitory concentrations (MICs) were quantified by liquid dilution assays. To screen for combinatorial effects, the Astragalus root extracts were combined with a range of conventional antibiotics and tested against each bacterial strain using liquid dilution assays. ΣFIC values were determined and used to determine the class of interaction. Results: Aqueous Astragalus root extracts did not significantly inhibit the growth of the non-pathogenic or beneficial gut microflora bacteria E. cloacae, E. coli or E. faecalis, but possessed mild inhibitory activity against pathogenic A. faecalis, A. hydrophila, B. cereus, S. newport and S. sonnei bacteria. Combinations of the Astragalus extracts and conventional antibiotics generally produced additive or indifferent interactions, indicating that they are safe to use concomitantly without compromising the efficacy of either component. Two cases of antagonistic combinations were detected against B. cereus and S. sonnei. Conclusion: Mild inhibition of 5 pathogenic bacteria occurred with aqueous Astragalus extracts, with a number of additive and antagonistic interactions arising when tested in combination with conventional antibiotics. Astragalus may be used safely in the presence of normal gut bacteria and in most combinations with conventional antibiotics. [ABSTRACT FROM AUTHOR]

The genus Terminalia contains some of the most widely used plants in traditional medicine. Many species possess antifungal, antibacterial, antiviral, antiprotozoal, analgesic, antidiarrheal, antioxidant, antimalarial, anticancer, and anti-inflammatory properties. Some species also have cardiovascular and wound-healing effects. Despite their myriad of traditional uses, relatively few studies have examined the medicinal properties and phytochemistry of most Australian Terminalia spp. The high tannin content of Terminalia spp. has been postulated to be a major contributor to the medicinal properties of this important genus. However, the complexities of tannins are generally believed to make them a poor choice for drug design. Therefore, much of the interest in Terminalia species has been for their nutraceutical and pharmacognostic value, and they remain under-explored in terms of drug discovery. Recent studies have identified many other important phytochemicals within Terminalia species apart from the tannins and have established that these compounds may contribute to their therapeutic bioactivities. Several Australian Terminalia species (particularly Terminalia carpentariae C.T. White, Terminalia catappa L., Terminalia ferdinandiana Exell and Terminalia grandiflora Benth) have received the most attention due to their reported high antioxidant contents. In contrast, other Australian Terminalia spp. have been relatively ignored. This review discusses recent studies into the phytochemistry, medicinal properties and the underlying therapeutic mechanisms of Australian Terminalia species to help direct future areas of research into this important genus. [ABSTRACT FROM AUTHOR]

Background: Embelica officinalis Gaertn. is an Indian plant which is known for its therapeutic properties. It is especially well known as a component of the Ayuverdic medicine Triphala. This study focuses on the growth inhibitory activity of E. officinalis fruit extracts against some bacterial triggers of autoimmune inflammatory diseases, both alone and in combination with conventional antibiotics. Methods: E. officinalis fruit powder was extracted with solvents of varying polarity and screened for bacterial growth inhibition by disc diffusion assay. The minimum inhibitory concentration (MIC) was quantified by both liquid dilution and disc diffusion techniques. To screen for combinatorial effects, the E. officinalis fruit extracts were combined with a range of conventional antibiotics and tested against each bacteria using a liquid dilution assay. Toxicity was examined using Artemia nauplii and HDF bioassays. Results: The ethyl acetate E. officinalis fruit extract displayed the strongest growth inhibitory activity against all of the bacterial triggers of autoimmune inflammatory disease. This extract was a particularly potent inhibitor of P. aeruginosa growth, with an MIC values as low as 264 μg/mL. The ethyl acetate extract was also a moderate to strong growth inhibitor of P. mirabilis, K. pneumonia and A. baylyi, with MIC values generally 1000-1500 μg/mL. The methanolic and aqueous extracts also inhibited the growth of all bacteria, although generally with only moderate to low activity. Whilst no synergistic interactions were detected in combinations containing the E. officinalis fruit extracts and conventional antibiotics, a number of combinations produced additive effects. These combinations are beneficial as they provide enhanced antibacterial efficacy compared to treatment with the antibiotic or extract components alone. No antagonistic interactions were detected. Therefore, use of the extracts in combination with conventional antibiotics would not compromise the antibiotics efficacy. All extracts were nontoxic in the Artemia nauplii and HDF toxicity assays, further indicating their potential for medicinal use. Conclusion: The E. officinalis fruit extracts were moderate inhibitors of the bacterial triggers of selected autoimmune inflammatory diseases. Furthermore, the extracts potentiated the activity of chloramphenicol and tetracycline against otherwise resistant bacterial strains. Isolation of the active compounds and the potentiating agents may be beneficial in antibiotic drug design. [ABSTRACT FROM AUTHOR]

Drug discovery and development is heavily biased towards the development of monotherapies. Screening, testing, and evaluation of mono-entity drugs are generally much simpler than drug combinations, and are generally easier to get approval from the regulatory authorities for their clinical use. However, monotherapy drugs may not have optimal activity, may have associated toxicities, or may lose activity over time as their target develops resistance. Drug combinations, often developed from existing monotherapies, may have improved efficacy and/or be less toxic. Furthermore, the existing drugs which have lost efficacy due to the development of resistance can often be re-activated by combining them with other chemical entities. Thus, whilst the current climate for drug approval, registration, and clinical use drives the majority of drug development research towards the development of monotherapies, combinations are often a substantial improvement on the original drug. This commentary examines monotherapy and combinational therapy models and discusses the benefits and limitations of each model. [ABSTRACT FROM AUTHOR]

Background: Roots from Glycyrrhiza glabra L. are known for their anti-inflammatory and antimicrobial properties. This study focuses on the growth inhibitory activity of G. glabra root extracts against some bacterial triggers of autoimmune inflammatory disease alone and in combination with conventional antibiotics. Methods: G. glabra root powder was extracted with solvents of varying polarity and screened for bacterial growth inhibition by disc diffusion assay. The minimum inhibitory concentration (MIC) was quantified by both liquid dilution and disc diffusion techniques. To screen for combinatorial effects, the G. glabra root extracts were combined with a range of conventional antibiotics and tested against each bacterium using liquid dilution assays. Where synergy was detected, the optimal ratios were determined using isobologram analysis. Toxicity was examined using an Artemia nauplii and HDF bioassays. Results: G. glabra root methanolic, aqueous and ethyl acetate extracts displayed antimicrobial activity against bacterial triggers of some autoimmune inflammatory diseases. The ethyl acetate extract was particularly potent, with MIC values <500 μg/mL against K. pneumoniae and A. baylyi. The aqueous extract was also a moderate inhibitor of A. baylyi. The methanolic extract had moderate inhibitory activity against all bacteria except P. aeruginosa. Of further note, the aqueous extract interacted synergistically in combination with chloramphenicol against K. pneumoniae (Σ FIC 0.49). All extracts were nontoxic in the Artemia and HDF toxicity assays, further indicating their potential for medicinal use. Conclusion: The G. glabra ethyl acetate root extract was a strong inhibitor of the growth of K. pneumoniae and A. baylyi and therefore has potential in the prevention and treatment of ankylosing spondylitis and multiple sclerosis. In addition, the aqueous root extract potentiated the inhibitory activity of chloramphenicol against a chloramphenicol resistant K. pneumoniae strain. Although the mechanisms of synergy are still unclear, compounds within the G. glabra root extracts may mimic the actions of resistance modifying agents. Isolation of these agents may be beneficial in antibiotic drug design against bacterial triggers of ankylosing spondylitis. [ABSTRACT FROM AUTHOR]

Introduction: The recent development of extensively antibiotic resistant bacteria has necessitated the search for novel anti-bacterial compounds. An examination of aromatic plants and traditional medicines is an attractive option for drug discovery. Phragmites australis (Cav.) Trin. Ex Steud. Reed is native to many regions globally, including Australia. It has yet to be tested for antibacterial activity. Materials and Methods: The ability of P. australis leaf extracts to inhibit the growth of a panel of bacterial pathogens was investigated by disc diffusion assay. Toxicity was examined using the Artemia franciscana nauplii bioassay. Results: P. australis leaf methanolic and aqueous extracts were completely ineffective at inhibiting the growth of gram-positive and gram-negative panels of bacteria. The extracts were nontoxic in the Artemia nauplii bioassay following 24 hr exposure. Conclusion: P. australis leaf extracts were completely ineffective bacterial growth inhibitors. However, these extracts may have other therapeutic properties and testing against protozoa, virus and tumour cells is required. [ABSTRACT FROM AUTHOR]

Introduction: Eupomatia laurina are trees native to Australia and Papua New Guinea. The fruit of this species are consumed as a bushfood. Infusions and decoctions produced from leaves and bark have reputed antiseptic properties and were used traditionally to treat a variety of bacterial diseases. Despite this, E. laurina fruit solvent extractions have not been rigorously examined for antibacterial properties against many pathogens. Methods: The antimicrobial activity of E. laurina fruit solvent extractions was investigated by disc diffusion and growth time course assays against a panel of pathogenic bacteria. The growth inhibitory activity was quantified by MIC determination. Toxicity was determined using the Artemia franciscana nauplii bioassay. Results: Methanolic and aqueous E. laurina fruit extracts inhibited the growth of a wide range of bacterial species. Growth of both gram positive and gram negative bacteria was inhibited by the E. laurina fruit extracts to approximately the same extent. With some noteable exceptions, the methanolic extracts were generally more potent than the aqueous extracts. The methanolic and aqueous E. laurina fruit extracts were particularly potent inhibitors of P. mirabilis growth, with MIC values as low as 83 µg/mL (aqueous extract against the P. mirabilis clinical isolate). The antibacterial activity of the methanolic E. laurina fruit extract was further investigated by growth time course assays which showed significant growth inhibition in cultures of K. pneumoniae and P. mirabilis within 1 h of exposure. All extracts were determined to be nontoxic in the Artemia franciscana nauplii bioassay, indicating their safety for internal use as well as for topical uses. Conclusions: The lack of toxicity of the E. laurina fruit extracts and their growth inhibitory bioactivity against a panel of pathogenic bacteria partially validate the traditional usage of these species to treat bacterial diseases and indicate their potential in the development of antiseptic agents. [ABSTRACT FROM AUTHOR]

Introduction: A. auriculiformis, A. disparrima and A. leptoloba are native Australian Acacia spp. which were used as both foods and medicines by the first Australians. Infusions and decoctions produced from leaves and bark have reputed antiseptic properties and were used traditionally to treat a variety of bacterial diseases. Despite this, Australian Acacia spp. solvent extractions have not been rigorously examined for antibacterial properties against food spoilage and food poisoning bacteria. Methods: The antimicrobial activity of A. auriculiformis, A. disparrima and A. leptoloba leaf extracts extractions was investigated by disc diffusion and growth time course assays against a panel of food spoilage and food poisoning bacteria. The growth inhibitory activity was quantified by MIC determination. Toxicity was determined using the Artemia franciscana nauplii bioassay. Results: A. auriculiformis, A. disparrima and A. leptoloba leaf extracts inhibited the growth of a wide range of bacterial species which cause food spoilage and food poisoning. A. auriculiformis extracts were generally more potent growth inhibitors than extracts prepared from the other species, although A. disparrima extracts were also potent inhibitors of bacterial growth. With few exceptions, the methanolic extracts were more potent growth inhibitors than the other solvent extractions. The methanolic A. auriculiformis leaf extract was a particularly potent inhibitor of K. pneumoniae and P. mirabilis, B. cereus and S. aureus growth, with MIC values of 97, 132, 178 and 109 µg/mL respectively. This extract was also a good inhibitor of A. faecalis, A. hydrophilia and S. newport growth (MIC's <1000 µg/mL range). The A. disparrima extracts had a similar, albeit slightly less potent activity profiles. In contrast, the A. leptoloba leaf extracts were substantially less potent. All extracts were determined to be nontoxic in the Artemia franciscana nauplii bioassay, indicating their safety for use as natural food preservatives. Conclusions: The lack of toxicity of the A. auriculiformis, A. disparrima and A. leptoloba leaf extracts and their growth inhibitory bioactivity against a panel of food spoilage and food poisoning bacteria indicate their potential in the development of natural food preservatives. [ABSTRACT FROM AUTHOR]

Introduction: Duboisia leichhardtii F.Muell. is a medium to large tree which is native to subtropical regions of eastern Australia. Duboisia spp. contain a number of psychoactive tropane and pyrrolidine alkaloids with reported antibacterial activity. Despite this, D. leichhardtii leaf extracts have not been rigorously examined for growth inhibitory properties against many bacteria, including the bacterial triggers of autoimmune inflammatory diseases. Methods: The antimicrobial activity of D. leichhardtii leaf solvent extracts was investigated by disc diffusion and growth time course assays against a panel of bacterial triggers of autoimmune diseases. The growth inhibitory activity was further quantified by MIC determination and growth time course assays. Toxicity was determined using the Artemia franciscana nauplii bioassay. Results: Methanolic and aqueous D. leichhardtii leaf solvent extracts were potent inhibitors of the bacterial triggers of rheumatoid arthritis and ankylosing spondylitis. The methanolic extract displayed the most potent bacterial growth inhibitory activity. It was particularly potent against P. mirabilis (MICs of 85 and 116 µg/mL against reference and clinical strains respectively) and P. vulgaris (MIC of 187 µg/mL). The methanolic extract was also a good inhibitor of K. pneumoniae growth (MICs of 143 and 118 µg/mL against reference and clinical strains respectively). The aqueous and ethyl acetate extracts were also potent bacterial growth inhibitors, albeit with higher MIC values. The antibacterial activity of the methanolic and aqueous D. leichhardtii leaf extracts were further investigated by growth time course assays which showed significant growth inhibition in cultures of P. mirabilis and K. pneumoniae within 1 h of exposure. All extracts were determined to be nontoxic in the Artemia franciscana nauplii bioassay, indicating their safety for use in preventing these autoimmune inflammatory diseases. Conclusions: The lack of toxicity of the D. leichhardtii leaf extracts and their growth inhibitory bioactivity against the bacterial triggers of rheumatoid arthritis and ankylosing spondylitis indicate their potential in the development of new therapies targeting the onset of these diseases. [ABSTRACT FROM AUTHOR]

Introduction: B. myrtifolia and S. anisatum are native Australian trees with uses as traditional medicines and bushfoods. Essential oils produced from leaves of these species have reputed antiseptic properties. Despite this, B. myrtifolia and S. anisatum leaf solvent extractions have not been rigorously examined for antibacterial properties against many pathogens. Methods: The antimicrobial activity of aqueous and methanolic leaf extracts of B. myrtifolia and S. anisatum was investigated by disc diffusion and growth time course assays against a panel of pathogenic bacteria. The growth inhibitory activity was quantified by MIC determination. Toxicity was determined using the Artemia franciscana nauplii bioassay. Results: Methanolic and aqueous B. myrtifolia and S. anisatum leaf extracts inhibited the growth of a wide range of bacterial species. Growth of both gram positive and gram negative bacteria was inhibited the B. myrtifolia and S. anisatum extracts to approximately the same extent. In general, S. anisatum extracts were more potent inhibitors of bacterial growth than were the B. myrtifolia extracts, and (with some noteable exceptions) the methanolic extracts were generally more potent than the aqueous extracts. The B. myrtifolia and S. anisatum extracts were particularly potent inhibitors of P. mirabilis growth, with MIC values as low as 105 µg/mL (aqueous S. anisatum extract). The antibacterial activity of the methanolic B. myrtifolia and S. anisatum extracts were further investigated by growth time course assays which showed significant growth inhibition in cultures of E. coli, K. pneumpniae and P. mirabilis within 1 h of exposure. All extracts were determined to be nontoxic in the Artemia franciscana nauplii bioassay, indicating their safety for internal use as well as for topical uses. Conclusions: The lack of toxicity of the B. myrtifolia and S. anisatum extracts and their growth inhibitory bioactivity against a panel of pathogenic bacteria partially validate Australian Aboriginal usage of these species as antiseptic agent and indicate their potential in the development of antiseptic agents. [ABSTRACT FROM AUTHOR]

Introduction: J. communis berry is a high antioxidant fruit which is used in several traditional medicinal systems to treat a variety of diseases including rheumatism, arthritis and gout. This study was undertaken to examine the inhibitory activity of J. communis berry extracts on the growth of several bacteria associated with autoimmune inflammatory disease, and to test their ability to block CaCo2 and HeLa cancer cell proliferation. Methods: J. Communis solvent extracts were prepared using solvents of varying polarity. The extracts were investigated by disc diffusion assay for the ability to inhibit the growth of a panel of pathogenic bacteria associated with autoimmune inflammatory diseases. Their MIC values were determined to quantify and compare their efficacies. Inhibitory activity against CaCo2 and HeLa human carcinoma cell lines was evaluated using an MTS colorimetric cell proliferation assay. Toxicity was determined using the Artemia franciscana nauplii bioassay. Results: The methanol, water and ethyl acetate J. communis berry extracts displayed moderate to potent growth inhibitory activity against bacterial triggers of rheumatoid arthritis, ankylosing spondylitis and multiple sclerosis. The methanol and water extracts displayed the broadest specificity, inhibiting the growth of all bacteria tested. The ethyl acetate extract also displayed antibacterial activity, inhibiting the growth of 9 of the 13 bacterial strains (69%). The ethyl acetate extract displayed the greatest potency, with MIC values substantially below 2000 µg/mL for all bacteria which it inhibited. It was most effective at inhibiting the growth of P. mirabilis, P. vulgaris and S. aureus, each with MIC's = 500 µg/mL. The methanol and water extracts also proved effective at blocking the proliferation of the colorectal cancer cell line CaCo2 and HeLa cervical cancer cell growth, with IC50 values in the 1300-2500 µg/mL range. All extracts were non-toxic in the Artemia nauplii bioassay. Conclusion: The lack of toxicity of the J. Communis berry extracts and their potent growth inhibitory bioactivity against bacteria and HeLa and CaCo2 carcinoma cells indicates their potential in the treatment and prevention of selected autoimmune inflammatory diseases and some cancers. [ABSTRACT FROM AUTHOR]

Background: Plants of the genus Acaciahave been used by Australian Aborigines to treat a variety of conditions including bacterial pathogens and inflammation. Despite this, many Acacia spp. have not been evaluated for the ability to inhibit the growth of bacterial triggers of autoimmune inflammatory diseases. This study evaluated the effects of Acacia disparrima and Acacia leiocalyx leaf extracts alone and in combination against some bacterial triggers of rheumatoid arthritis, ankylosing spondylitis and multiple sclerosis. Results: Acacia disparrima and Acacia leiocalyx leaf extracts displayed noteworthy antibacterial activity against several bacterial triggers of autoimmune diseases. The methanolic extracts were particularly good inhibitors of P. mirabilis, K. pneumoniae, and A. baylyi with MIC values <1000µg/mL, but were ineffective against P. aeruginosa. Furthermore, combining the extracts with conventional antibiotics resulted in significant potentiation of the inhibitory activity for some combinations. Interestingly, all of the synergistic interactions contained tetracycline as the antibiotic component, whilst all of the antagonistic combinations contained either gentamicin or ciprofloxacin as the antibiotic component. None of the individual components (nor the combinations) were toxic in the ALA assay. Conclusion: The majority of combinational effects were either additive or indifferent, thereby alleviating some concern related to the concurrent use of A. disparrima and A. leiocalyx whilst also taking conventional antibiotics. A few notable combinations were identified, indicating the need for further in vivo testing. [ABSTRACT FROM AUTHOR]

Introduction: High antioxidant capacities have been linked to the treatment of rheumatic diseases and in the inhibition of microbial growth. Recent reports have identified several native Australian culinary herbs with high antioxidant capacities. Despite this, several of these species are yet to be tested for the ability to inhibit the growth of the bacterial triggers of autoimmune inflammatory diseases. Methods: Solvent extracts prepared from selected Australian culinary herbs were analysed for antioxidant capacity by the DPPH free radical scavenging assay. Growth inhibitory activities against bacterial species associated with initiating rheumatoid arthritis and ankylosing spondylitis were determined by disc diffusion assay and quantified by MIC determination. Toxicity was determined by Artemia franciscana bioassay. Results: Methanolic extracts of most plant species displayed relatively high antioxidant contents (equivalent to approximately >10 mg of vitamin C per gram of fruit extracted). Most aqueous extracts also contained relatively high antioxidant capacities. The ethyl acetate and chloroform extracts generally had lower antioxidant capacities than the more polar extracts. In contrast, the hexane extracts of all species had low antioxidant contents (generally < 0.5 mg of vitamin C per gram of fruit extracted). Interestingly, the bacterial growth inhibitory activity of the extracts did not correlate with their antioxidant capacities. With the exception of native thyme, the herb extracts with the highest antioxidant capacities had only low antibacterial activity, with MIC values generally well in excess of 4000 µg/ml against all bacterial species. In contrast, many of the ethyl acetate extract and hexane extracts, which had low range antioxidant capacities (generally < 5 mg ascorbic acid equivalents/g extracted), had potent bacterial growth inhibitory activity with many MIC values substantially below 1000 µg/ml). The river mint ethyl acetate extract displayed toxicity in the Artemia franciscana bioassay (LC50=186 µg/mL). All other extracts were nontoxic. Conclusion: The lack of toxicity and inhibitory activity against microbial triggers of rheumatoid arthritis and ankylosing spondylitis by the Australian native culinary herb extracts indicates their potential in the treatment and prevention of these diseases. [ABSTRACT FROM AUTHOR]

Cock.: Medicinal Plant Images 144 Pharmacognosy Communications, Vol 11, Issue 2, Apr-Jun, 2021 5. A multifaceted peer reviewed journal in the field of Pharmacognosy and Natural Products www.phcogcommn.org Medicinal Plant Images Pharmacognosy Communications, Vol 11, Issue 2, Apr-Jun, 2021 143 Ian Edwin Cock 1,2,* 1 Environmental Futures Research Institute, Nathan Campus, Griffith University, 170 Kessels Rd, Nathan, Brisbane, Queensland 4111, AUSTRALIA. Email id: i.cock@griffith.edu.au DOI: 10.5530/pc.2021 .2.27 Medicinal Plant Images Figure 2: Scaevola spinescens (commonly known as currant bush, maroon bush and prickly fanflower) is an endemic Australian plant which is distributed in arid areas of the Australian continent, particularly in the western regions. [Extracted from the article]

Acute diarrhoea is becoming a major public health problem in Malaysia, with more than 13.5 million cases reported annually. Foodborne bacterial pathogens are a predominant cause of diarrhoea, with infections causing prolonged illness durations and higher patient mortality rates, placing a tremendous burden on the Malaysian economy. Due to increasing incidences of diarrhoea in Malaysia caused by foodborne pathogens and the increasing levels of resistance towards antibiotics from many different classes, new drugs and/or therapies are urgently required. The evidence for plants as new sources of antibiotics has increased dramatically in recent years and there has been a substantial increase in interest in traditional and herbal medicines. Several Terminalia spp. are native to Malaysia, with previous research demonstrating that Terminalia spp. are rich in therapeutic phytochemicals and possess antibacterial properties. However, limited research has been conducted on the native Malaysian Terminalia spp. for their potential as new antibacterial therapies. The current review discusses the types of bacteria, including antibioticresistant strains, that cause food poisoning in Malaysia, and reports the phytochemical content and antibacterial properties of eight of these useful plant species. Future directions pertaining to drug discovery pathways are also suggested. [ABSTRACT FROM AUTHOR]

Background: Recent declines in new antibiotic discovery and the increase in antibiotic resistance have resulted in failing against bacterial pathogens. To develop novel antibiotic therapies, medical researchers have begun to focus on traditional therapies. Combinational therapies consisting of medicinal plants and conventional antibiotics may reactivate current drugs that are otherwise ineffective against antibioticresistant bacteria. Terminalia sericea Burch. Ex DC, Terminalia prunioides Laws. and Terminalia gazensis Bak. f. are native South African plants with antimicrobial properties. However, combinations of Terminalia sericea, Terminalia prunioides and Terminalia gazensis with conventional antibiotics are yet to be evaluated for growth inhibitory activity against gastrointestinal pathogens. Methods: Terminalia spp. leaves were extracted with solvents of varying polarity. Antimicrobial screening was performed using disc diffusion and broth microdilution assays. Toxicity was measured using Artemia franciscana nauplii lethality assays. Results: All extracts (except the T. sericea extracts) showed low to moderate inhibitory activity against B. cereus and E. faecalis, A. faecalis, A. hydrophilia, S. sonnei and S. newport in both the disc diffusion and liquid dilution assay. Twenty-three extract/antibiotic combinations produced synergy, 26 were additive, 24 were non-interactive and seven were antagonistic. Most of the antagonist interactions occurred in combinations containing gentamicin. All extracts were either non-toxic or of low toxicity in the Artemia bioassay. Conclusion: Terminalia spp. extracts may mimic the actions of a resistance modifying agents, enhancing the activity of several antibiotics that are relatively ineffective alone. Further studies are required to identify the bioactive and potentiating components and their mechanisms of action. [ABSTRACT FROM AUTHOR]