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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: 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: 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: Cinnamomum oliveri F. M. Bailey is a rain forest tree native to Australia. Decoctions, infusions and essential oils produced from the leaves were used traditionally to treat a variety of bacterial diseases. Despite this, C. oliveri leaf extractions have not been rigorously examined for antibacterial properties against many pathogens. Methods: The antimicrobial activity of C. oliveri 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: C. oliveri 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 C. oliveri leaf extracts to approximately the same extent. The methanolic extracts were generally most potent growth inhibitors. The methanolic, aqueous and ethyl acetate C. oliveri leaf extracts were particularly potent inhibitors of P. mirabilis growth, with MIC values as low as 127 µg/mL (methanolic extract). A. coli, K. pneumoniae and B. cereus were also particularly susceptible to the methanolic, aqueous and ethyl acetate extracts, with MIC values generally substantially <1000 μg/mL. The antibacterial activity of the methanolic C. oliveri leaf extract was further investigated by growth time course assays which showed significant growth inhibition in cultures of E. coli, 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 C. oliveri leaf 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: Swainsona formosa is a legumous plant which is endemic to the arid inland regions of Australia. Several Swainsona spp. were valued by the first Australian for their antiseptic properties and were used traditionally to treat a variety of bacterial diseases. Despite this, S. formosa solvent extractions have not been rigorously examined for antibacterial properties against many bacterial pathogens. Methods: The antimicrobial activity of S. formosa leaf 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: S. formosa leaf extracts inhibited the growth of a wide range of gram positive and gram negative bacteria. The methanolic extracts were generally more potent than the aqueous extracts. The methanolic and aqueous S. formosa leaf extracts were particularly potent inhibitors of A. faecalis, A. hydrophilia, K. pneumoniae, P. mirabilis, B. cereus, S. aureus and S. pyogenes growth, with MIC values substantially <1000 μg/mL and as low as 150 μg/mL against some bacteria (methanolic extract against P. mirabilis). The antibacterial activity of the methanolic and aqueous S. formosa leaf extracts was further investigated by growth time course assays which showed significant growth inhibition in cultures of all bacterial species within 1 h of exposure. All extracts were determined to be nontoxic in the Artemia franciscana nauplii bioassay, indicating their safety for therapeutic uses. Conclusions: The lack of toxicity of the S. formosa leaf extracts and their growth inhibitory bioactivity against a panel of pathogenic bacteria indicate their potential in the development of antiseptic agents. [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: 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: Leptospermum longifolium (C.T. White & W.D. Francis) S.T. Blake, Leptospermum petersonii Bailey and Melaleuca alternifolia (Maiden & Betche) Cheel are aromatic native Australian trees with uses as traditional medicines. Essential oils produced from leaves of these species have reputed antiseptic properties against many bacteria. Despite this, L. longifolium, L. petersonii and M. alternifolia leaf solvent extractions have not been rigorously examined for antibacterial properties against many pathogens. Methods: The antimicrobial activity of methanolic L. longifolium, L. petersonii and M. alternifolia leaf 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: The methanolic L. longifolium, L. petersonii and M. alternifolia leaf extracts inhibited the growth of a wide range of bacterial species. Growth of both gram positive and gram negative bacteria was inhibited by all extracts. The L. longifolium and L. petersonii extracts were generally more potent inhibitors of bacterial growth than was the M. alternifolia extract against most bacterial species. A. hydrophilia, C. freundi, P. mirabilis and B. cereus growth was particularly susceptible to the extracts, with MIC values as low as 147 µg/mL (inhibition of A. hydrophilia growth by the L. longifolium extract). The antibacterial activity of the L. longifolium, L. petersonii and M. alternifolia extracts were further investigated by growth time course assays, with significant growth inhibition recorded in all cultures within 1 h of exposure. All extracts were determined to be nontoxic in the Artemia franciscana nauplii bioassay, indicating their safety for therapeutic uses. Conclusions: The lack of toxicity of the methanolic L. longifolium, L. petersonii and M. alternifolia leaf extracts and their growth inhibitory bioactivity against a panel of pathogenic bacteria partially validate Australian Aboriginal usage of these species as antiseptic agents and indicate their potential in the development of antiseptic agents. [ABSTRACT FROM AUTHOR]