Effect of growing area on total polyphenols, flavonoids, tannins and antimicrobial activity in quercus suber l. Acorn oil

Abstract

The investigation was conducted on oil extracted from mature acorns of Quercus suber L. harvested from three different Tunisian sites. The content of total polyphenols, tannins and flavonoides were determined. Antimicrobial activities were also evaluated. Antimicrobial activity of this oil was tested against: Escherichia Coli, Bacillus subtilis and Candida albicans. Gentamicin and amphotericin B were respectively used as a positive reference for bacteria and fungi. Discs without samples were used as a negative control. Fixed oil of cork oak acorn was extracted by the soxhlet apparatus. The oil content, expressed as dry weight, ranged from 0.9 to 2.02%. Fixed oil extracted from acorns of cork oak showed a high amount of total polyphenols 18.93 mg GAE/g. Amounts of flavonoids and tannins were also important. The results showed a significant antimicrobial effect against B. subtilis and C. albicans with inhibition diameter of 10.6 mm and 9.8 mm, respectively.