Characterization of antioxidant and antimicrobial isolates from Quercus brantii L. extract

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2011
Nebigil, Can
This study was designed for the investigation of antioxidative, and antimicrobial properties of Quercus brantii L. (Q.brantii.) seed extract. Phenolic profile of the total extract was determined by using High Performance Liquid Chromatography (HPLC) and confirmed by High Resolution Mass Spectroscopy (HRMS). Solvent fractionation was performed to seperate bioactive compounds in total extract by using solubility differences. In comparison of fractions, ethyl acetate and diethyl ether phases have revealed highest antioxidant effect. Due to the low yield and high number of the molecules in ethyl acetate fraction, HRMS was used to characterize the compounds. On the other hand, in diethyl ether fraction, there was a single major compound which showed high antioxidant activity. The major compound, was purified by column chromatography and characterized by NMR, IR and HRMS as methyl gallate. E.coli, P.mirabilis, S.aureus, S.pyogenes bacterial strains were used to determine the antimicrobial activity of Q. brantii seed crude extract, fractions and isolated compound by disc diffusion, MIC and MBC methods. Isolated methyl gallate and ethyl acetate fraction displayed a significant effect on all bacterial strains as high as reference antibiotics. Consequently, crude Q. branti extract, isolated methyl gallate and ethyl acetate fraction could be considered as powerful antimicrobial agents, and at the same time efficacious antioxidants.