Functional contents and antioxidant potency of Chinese Wenguan flower tea

Wenguan Tea, composed of dried buds or flowers of Xanthoceras sorbifolia, has become popular in the north of China because of its special flavor and health benefits. The present study aims to propose a method for rapid identification of bioactive components in different edible parts of X. sorbifolia, to modulate the quality control. And a bioactivity-guided phytochemical study was further performed, directly providing the functional components in Chinese Wenguan Tea. Compared with four common commercial flower teas, Wenguan tea with the second greatest total flavonoids (0.261%) and phenolic acid (1.441%), exhibited comparable scavenging radical values and ferric-reducing power. UPLC-MS/MS analyses revealed the chemical profile of the flowers and buds. Furthermore, antioxidant potency-oriented phytochemical research led to the critical phenolic constituents (W1–W7). Among them, flavonoids W3 (myricitrin), W4 (isoquercitrin), W7 (quercitrin) could significantly inhibit intracellular ROS generation, reduce cell apoptosis, and decrease oxidative stress damage in H2O2-induced Hep3B cells in a manner of Nrf2-dependent mechanism. Overall, findings from this study exemplify a clear classification of original species for producing Wenguan Tea using flowers not buds of X. sorbifolia, and further clarified the potential pharmaceutical agents against oxidative stress as a functional tea.