Biological Activities of Oligopeptides Extracted from Northern Fujian Oolong Tea

Crude extract of oligopeptideswas prepared from Fujian oolong teas produced in northern regions to obtain thechemical segments with a molecular weight ranging from 500 Da to 1500 Da bymembrane separation. The in vitro anti-glycemic, antilipemic, andantioxidant activities of the preparation were determined in laboratory. Thesemi-inhibitory concentration (IC₅₀) of the tea oligopeptides on α-glucosidasewas found to be 0.093 mg·mL^-1 and the binding rates with sodiumcholate, sodium taurocholate, and sodium glycholate 24.26%, 24.10%, and 23.66%,respectively. The IC₅₀ on DPPH (1, 1-diphenyl-2-picrhydrazyl) freeradical was 0.033 mg·mL^-1,which was higher than that of glutathione at 0.099 mg·mL^-1, suggesting potential antidiabeticand antioxidant abilities of the extract. The preliminary results obtained witha new perspective of the oligopeptides seemed to present a promisingapplication of the oolong tea.