evaluation of antiradical and antimicrobial activity of methanolic extract of two acorn varieties and detection of phenolic compound with high performance liquid chromatography

in this study, total phenolics and flavonoids content, antiradical and antimicrobial activity of methanolic extract of two iranian acorn varieties, namely quercus.castaneifolia var castaneifolia and quercus.branti var persica were evaluated. total phenolic and flavonoid content and extraction yield of methanolic extract of castaneifolia variety (mc) were significantly higher than that of the extract of persica variety (mp). extracts were also tested for their antioxidant activities using scavenging activity of 2, 2-diphenyl-1-picrylhydrazyl and compared with synthetic antioxidant namely bha and bht. ec50 values for mc, mp, bha and bht were 42.84, 70.40, 89.46 and 41.73 mg/ml, respectively. the extracts also showed good antimicrobial activity against all of tested microorganisms and the tested gram-negative bacteria was more resistant to the inhibitory effect of extracts. the ranges of minimum inhibitory concentration (mic) of the extracts were 0.312-5 and 1.25-5 mg/ml for mc and mp, respectively. there was no difference between the mic of mc and mb extract against salmonella typhi and shigella dysenteriae but mc extract showed the strongest activity on escherichia coli and yersinia entrocolitica at lower concentration. mp extract at concentration of 5mg/ml had bactericidal effect on all of gram negative bacteria (except citrobacter). the most efficient bactericidal activity of mc extract was against bacillus cereus, with mbc = 0.312 mg/ml while shigella dysenteriae had the highest mbc (10mg/ml). a high-performance liquid chromatography was used for determination of phenolic acids of extracts. gallic, caffeic, p-coumaric and cholorogenic acid were found in mc and gallic, caffeic, cholorogenic and sirinjic acid were detected in mp extract.