14E-30 |
Phenolic antioxidants from Oregano (Origanum vulgare) with antimicrobial activity against Helicobacter pylori |
S. S. CHUN, Y. T. Lin, D. A. Vattem, and K. Shetty. Dept. of Food Science, Univ. of Massachusetts, Amherst, Chenoweth Lab., Amherst, MA 01003-1410 Many phenolic compounds in plant are good sources of natural antioxidants. Phenolic compounds in foods have benefits due to inhibitory effects against mutagenesis and carcinogenesis. Some phenolics are also responsible for antimicrobial and antifungial effects. Oregano ( Origanum vulgare L. ) has been reported to contain phenolic compounds with antioxidant properties and antimicrobial activity. In our laboratory we have found several oregano clonal lines containing high phenolics with antioxidant and antimicrobial potential. The aim of our investigation was to determine the phenolic profiles related antioxidant activity of oregano clonal extracts, and evaluate the antimicrobial activity against Helicobacter pylori. In all cases clonal extracts were compared to commercial mixtures. Water and 60% ethanol extracts from oregano clonal lines and the commercial heterogenous mixtures were prepared. Total phenolics were assayed using the Folin-Ciocalteu method. Antioxidant activities were measured by 1,1-diphenyl-2-picrylhydrazyl-2-radical ( DPPH ) method, antioxidant protection factor ( PF ) method using b-carotene, 3-ethyl benzthiazoline-6-sulfonic acid ( ABTS+ ) method and TBARS. Antimicrobial activity against H.pylori was tested by the standard agar diffusion method. Phenolic profiles in oregano extracts were analyzed using HPLC. Total phenolics were the highest in 60% ethanol extracts of clonal oregano. DPPH scavenging activity depended on the kind of phenolic compound and percentage inhibition activity (ABTS+ ) depended on amount of total phenolics. TBARS and PF were related to lipophilic compounds in oregano. The differences in phenolic acids consisting of C6-C1-COOH, and C6-C3-COOH structures were hypothesized to play a role in growth inhibition of H. pylori. The results obtained give an insight into the mechanism of antimicrobial activity of different phenolics and can be used in designing food ingredients and natural antimirobials for food preservation and functional food applications.
Session 14E, Nutraceuticals & Functional Foods: General I
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