Phenolic acids significantly contribute to antioxidant potency of Gynostemma pentaphyllum aqueous and methanol extracts

Cyclic voltammetry, as well as four well-established spectrophotometric and fluorimetric assays, were applied to study the contribution of phenolic compounds to the antioxidant capacity of aqueous and methanol extracts of Jiaogulan tea (Gynostemma pentaphyllum). In addition, individual phenolic acid profiles of G. pentaphyllum extracts, determined using UPLC–MS/MS, were reported for the first time in this study. Methanol extraction resulted in higher contents of phenolic compounds, as well as antioxidant capacity of tested extracts. Our results suggest that G. pentaphyllum aqueous and methanol extracts have high antioxidant capacity and are rich in phenolic compounds, such as chlorogenic acid, which might play a role in the prevention of type 2 diabetes mellitus and cardiovascular disease.