Assessment of anti-oxidant activity of plant extracts using microbial test systems |
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Authors: | O. Oktyabrsky G. Vysochina N. Muzyka Z. Samoilova T. Kukushkina G. Smirnova |
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Affiliation: | Laboratory of Physiology and Genetics of Microorganisms, Institute of Ecology and Genetics of Microorganisms, Russian Academy of Sciences, Perm, Russia; Laboratory of Phytochemistry, Central Siberian Botanical Garden, Siberian Division of Russian Academy of Sciences, Novosibirsk, Russia |
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Abstract: | Aims: To evaluate the anti-oxidant properties of extracts from 20 medicinal herbs growing in western Siberia using microbial test systems and different in vitro methods. Methods and results: In vivo anti-oxidant activity of extracts was evaluated for their capacity to protect bacteria, Escherichia coli , against bacteriostatic and bactericidal effects of H2O2 and menadione, and action on anti-oxidant gene expression. In vitro anti-oxidant activity has been examined by a number of methods including: the 1,1-diphenyl-2-picrylhydrazyl radical (DPPH•)-scavenging assay, chelating activity and capacity to protect plasmid DNA against oxidative damage. In addition, total polyphenol content was determined. The extracts of Fragaria vesca , Rosa majalis , Pentaphylloides fruticosa , Alchemilla vulgaris and Pulmonaria mollis possessed the highest levels of anti-oxidant activity in vivo and in vitro . The protective properties were more closely related to the DPPH• radical-scavenging activity, tannin content and action on anti-oxidant gene expression than to other parameters. Conclusion: The extracts of medicinal plants may have anti-oxidant effects on bacteria simultaneously through several different pathways, including direct inhibition of reactive oxygen species, iron chelation and anti-oxidant genes induction. Significance and Impact of the Study: Using microbial test systems, we revealed herbs that may be used as potential sources of natural anti-oxidants. |
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Keywords: | anti-oxidant activity Escherichia coli gene expression plant extracts |
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