Extraction of Flavonoids from T etrastigma hemsleyanum Diels et Gilg and Their Antioxidant Activity

Abstract

The Box–Behnken design was used to optimize the extraction conditions of total flavonoids from Tetrastigma hemsleyanum. The effects of four independent variables, including extraction temperature, extraction time, number of extraction and the ratio of liquid to raw material, on flavonoids yield were determined. The experimental data were fitted to a second-order polynomial equation using multiple regression analysis and also analyzed using the appropriate statistical methods. The optimum extraction conditions were at extraction temperature of 80C, extraction time of 2.1 h, number of extraction of 3 and ratio of liquid to raw material of 17.6 mL/g. Under these conditions, the experimental flavonoids yield was 1.23 ± 0.09%, which was in good agreement with the predicted value. The antioxidant activities of the flavonoids, including the scavenging activity of ABTS (2,2′-azinobis(3-ethyl-benzothiazoline-6-sulfonic acid) diammonium salt), DPPH (1,1-diphenyl-2-picrylhydrazyl) and ferric reducing antioxidant power assay, were examined. The data obtained from our study clearly demonstrate the antioxidant potency of the flavonoids extracted from the roots of T. hemsleyanum. Practical Applications Many studies have been carried out to find new sources of natural antioxidants because they are environmentally friendly and have no health hazards. In particular, interest has intensified in the flavonoids present in the normal human diet and in many folk medicines still in use. Tetrastigma hemsleyanum is a herbaceous perennial species native to China. In this study, the extraction conditions of flavonoids from the roots of T. hemsleyanum were optimized and studies demonstrated that the flavonoids possessed potent antioxidant activity. Therefore, the flavonoids have the potential to be used in food systems.