Biological activities of various fractions of black wattle bark tannins.
Yao Kai; Lü Yuanping; He Qiang; Jia Dongying; Shi Bi.College of Light Industry and Food Engineering, Sichuan University, Chengdu 610065, P.R.China.
The tannin fractions with different molecular weight were obtained by purifying and fractionating black wattle( Acacia mearnsii ) bark tannins and their biological activities were studied. The data indicated that the tannin fractions with higher molecular weight possessed stronger reactivity with gelatin and greater inhibitory effects on certain hydrolases and that the fractions with moderate molecular weight showed higher antimicrobial activity. Meanwhile, it was found that the pH value and mass ratio of reactants were also factors influencing the biological activities. The results prove that it is of significance to utilize vegetable tannins in finer degree.