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.

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 fruits 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 selectedAustralian native fruits 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 spondylitiswere determined bydisc diffusion assay and quantified by MIC determination. Toxicity was determined by Artemia franciscana bioassay. Results: Methanolic extracts of all plant species displayed high antioxidant contents (equivalent to approximately 7-16 mg of vitamin C per gram of fruit extracted). Most aqueous extracts also contained relatively high antioxidant capacities. In contrast, the ethyl acetate, chloroform and hexane extracts for most species (except lemon aspen and bush tomato) had lower antioxidant contents (below 1.5 mg of vitamin C equivalents per gram of plant material extracted). Interestingly, the bacterial growth inhibitory activity of the extracts did not correlate with their antioxidant capacities. The fruit extracts with the highest antioxidant capacities (lemon aspen and desert lime methanolic extracts) had only low antibacterial activity, with MIC values generally >10,000 µg/ml against all bacterial species. In contrast, the Illawarra plum and desert lime ethyl acetate extracts, which had mid-range antioxidant capacities (1-6.5 mg ascorbic acid equivalents/g extracted), had potent bacterial growth inhibitory activity (200-400 µg/ml). The native tamarind ethyl acetate extract displayed low-moderate toxicity in the Artemia franciscana bioassay (LC50valuesbelow 1000 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 fruit extracts indicates their potential in the treatment and prevention of these diseases.

Background:High antioxidant capacities have been linked to the treatment and prevention of several cancers. Recent reports have identified several native Australian fruits with high antioxidant capacities. Despite this, several of these species are yet to be tested for anticancer activity.Materials and Methods:Solvent extracts prepared from high antioxidant native Australian fruits were analyzed for antioxidant capacity by the di (phenyl)-(2,4,6-trinitrophenyl) iminoazanium free radical scavenging assay. Antiproliferative activities against CaCo2 and HeLa cancer cells were determined by a multicellular tumor spheroid-based cell proliferation assay. Toxicity was determined by Artemia franciscana bioassay.Results:Methanolic extracts of all plant species displayed high antioxidant contents (equivalent to approximately 7–16 mg of vitamin C per gram of fruit extracted). Most aqueous extracts also contained relatively high antioxidant capacities. In contrast, the ethyl acetate, chloroform, and hexane extracts of most species (except lemon aspen and bush tomato) had lower antioxidant contents (below 1.5 mg of vitamin C equivalents per gram of plant material extracted). The antioxidant contents correlated with the ability of the extracts to inhibit proliferation of CaCo2 and HeLa cancer cell lines. The high antioxidant methanolic extracts of all species were potent inhibitors of cell proliferation. The methanolic lemon aspen extract was particularly effective, with IC50 values of 480 and 769 μg/mL against HeLa and CaCo2 cells, respectively. In contrast, the lower antioxidant ethyl acetate and hexane extracts (except the lemon aspen ethyl acetate extract) generally did not inhibit cancer cell proliferation or inhibited to only a minor degree. Indeed, most of the ethyl acetate and hexane extracts induced potent cell proliferation. The native tamarind ethyl acetate extract displayed low-moderate toxicity in the A. franciscana bioassay (LC50 values below 1000 μg/mL). All other extracts were nontoxic. A total of 145 unique mass signals were detected in the lemon aspen methanolic and aqueous extracts by nonbiased high-performance liquid chromatography-mass spectrometry analysis. Of these, 20 compounds were identified as being of particular interest due to their reported antioxidant and/or anticancer activities.Conclusions:The lack of toxicity and antiproliferative activity of the high antioxidant plant extracts against HeLa and CaCo2 cancer cell lines indicates their potential in the treatment and prevention of some cancers.SUMMARY Australian fruit extracts with high antioxidant contents were potent inhibitors of CaCo2 and HeLa carcinoma cell proliferationMethanolic lemon aspen extract was particularly potent, with IC50 values of 480 μg/mL (HeLa) and 769 μg/mL (CaCo2)High-performance liquid chromatography-mass spectrometry-quadrupole time-of-flight analysis highlighted and putatively identified 20 compounds in the antiproliferative lemon aspen extractsIn contrast, lower antioxidant content extracts stimulated carcinoma cell pr...

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