Tetrastigma hemsleyanum Diels et Gilg Roots from Different Origins: Pharmacognostical Identification, Content Determination of Functional Composition and in vitro Antioxidant Activity

Tetrastigma hemsleyanum Diels et Gilg (T. hemsleyanum) is a unique and rare Chinese medicinal herb mainly distributed in the south of the Yangtze River in China. In the present study, T. hemsleyanum roots from seven different sites in the south of the Yangtze River (Guangxi [Baise, Guilin, and Hechi], Hunan [Fenghuang], and Zhejiang [Hangzhou, Taizhou, and Wenzhou] provinces) were collected, and differences in the macroscopic and microscopic appearance of the roots, content of their active ingredients, and antioxidant activity of the root extracts were analyzed. The Pearson correlation coefficient was used to analyze the correlation between the antioxidant activity and the total flavonoids and total polyphenols contents of T. hemsleyanum roots. The results of macroscopic and microscopic root appearance indicated that T. hemsleyanum roots from different sites could be clearly differentiated based on size and epidermal characteristics, the color of dry root powder, and the shape and arrangement of the root canal. The results of content determination showed no significant differences (P>0.05) between the contents of flavonoids, polyphenols, rutin, and catechin in T. hemsleyanum roots from Guilin, Guangxi, and those from Zhejiang and Hunan. However, the contents of quercetin and kaempferol showed a significant difference (P<0.01) between T. hemsleyanum roots from Guilin, Guangxi, and those from Zhejiang, Hunan, and Guangxi (Baise and Hechi). Furthermore, the root extracts of T. hemsleyanum showed a high antioxidant activity ranging from 2.254±0.240 to 14.655±4.528 mg ascorbic acid equivalent/g sample. Pearson correlation analysis showed that the antioxidant activity of T. hemsleyanum roots had a higher correlation with the total flavonoids content than with the total polyphenols content. The results of this study provided a reference for the quality evaluation of T. hemsleyanum from different origins and provided technical support for subsequent resource development.