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Background: Terminalia ferdinandiana Exell. fruit have been used by the First Australians as a nutritious food and as a medicine for thousands of years. The antibacterial properties of T. ferdinandiana fruit extracts are well reported. However, the therapeutic potential of plants growing in different locations and environmental conditions have not previously been compared. Aim: This study compares the antibacterial efficacy of fruit harvested from two distinct locations in Australia and correlates these activities with their physiochemical properties. Materials and Methods: The growth inhibitory activity of the T. ferdinandiana fruit extracts were evaluated using solid phase disc diffusion and liquid microdilution MIC assays. Artemia nauplii bioassays were used to screen and compare the extracts from both locations. Results: The T. ferdinandiana extracts prepared from fruits sourced from the two distinct regions of Australia inhibited the growth of the panel of bacteria screened, including a highly antibiotic MRSA strain. In general, the methanolic extracts were substantially better inhibitors of bacterial growth than the aqueous extracts, and extracts prepared using the Northern Territory (NT)-derived fruit were substantially more potent than the Western Australian (WA) fruit extracts. MICs substantially <1000 μg/mL were noted for the NT methanolic fruit extract against the reference S. aureus and MRSA bacterial strains respectively. The potency of this extract against the MRSA strain indicates that this extract may function via a distinct mechanism compared to the standard antibiotics tested. Interestingly, the greater antibacterial potency of the NT fruit extracts correlated to high ascorbic acid levels, indicating that the antibacterial mechanism may involve modulation of the redox state. All extracts were nontoxic in the Artemia nauplii toxicity assay, indicating their safety for therapeutic usage. Conclusion: The T. ferdinandiana fruit extracts prepared from both NT and WA each had noteworthy antibacterial activity, although greater activity was noted for the NT fruit extracts. This activity correlated with the antioxidant/ascorbic acid content of the extracts. All extracts were also nontoxic in the Artemia nauplii bioassay, although future studies using mammalian cell lines are required to confirm their safety for therapeutic use. [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: 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 recent development of extensively antibiotic resistant bacteria has necessitated the search for novel antibacterial compounds. An examination of aromatic plants and traditional medicines is an attractive option for drug discovery. Astrotrichia latifolia Benth. is a native Australia shrub that has yet to be tested for antibacterial activity. Methods: The ability of A. latifolia 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: A. latifolia leaf methanolic and aqueous extracts were completely ineffective at inhibiting the growth of gram-positive and gram-negative panels of bacteria. The extracts were non-toxic in the Artemia nauplii bioassay following 24 h exposure. Conclusion: A. latifolia 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: 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: 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: 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]