Antimicrobial and antioxidant activities of essential oil and crude extracts of Hypericum tetrapterum Fries (Hypericaceae)

Abstract

In vitro antimicrobial activity of essential oil and crude extracts (petroleum ether, ethyl acetate and methanol extract) of Hypericum tetrapterum Fries (Hypericaceae) were investigated by disc diffusion and dilution methods. The studied samples were active against a panel of standardized bacteria and fungi. The maximum antimicrobial activity was shown by the essential oil and the petroleum ether extract. The antioxidant activity of the examined oil and extracts was determined by free radical scavenging assay and a phosphomolybdenum method. Both methods showed that the methanol crude extract of H. tetrapterumhad the highest antioxidant capacity among all samples investigated. The results of the pharmacological tests were discussed with respect to up to now known constituents of essential oil and crude extracts of H. tetrapterum. A correlation between the total flavonoid content and the antioxidant activity was observed. To the best of our knowledge this is the first report about the antimicrobial and antioxidant activities of the essential oil, crude petroleum ether and ethyl acetate extracts of H. tetrapterum. Key words: Hypericum tetrapterum Fries, Hypericaceae, antimicrobial activity, antioxidant activity, essential oil, crude extracts.