Triterpenoids from the leaves of Camellia chrysantha growing in Quang Ninh (Vietnam) and their activities on main protease (M^pro) and ACE2

Abstract

Camellia chrysantha (Hu) Tuyama (Theaceae) is used as a high‐class herbal tea called “yellow camellia”, “golden camellia”, “camellia queen”. Phytochemical investigation of the leaves of C. chrysantha led to the isolation of four triterpenoids β‐amyrin hexanoate (1), friedelin (2), friedelanol (3), β‐amyrin (4) together with one steroid chondrillasterol (5). Their chemical structures were established based on analysis of their spectroscopic data including 1D, 2D‐NMR, MS data and comparing with literatures. It is the first time β‐amyrin hexanoate and chondrillasterol were isolated from the genus Camellia, and similarly for friedelin, friedelanol and β‐amyrin from C. chrysatha. Beta‐amyrin hexanoate which presents a high amount in the leave of C. chrysantha, exhibited the enzyme inhibitory activity against 3CL^pro/M^pro but non‐toxicity toward normal Vero cells.