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

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 beta-amyrin hexanoate ( 1), friedelin (2), friedelanol (3), beta-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 beta-amyrin hexanoate and chondrillasterol were isolated from the genus Camellia, and similarly for friedelin, friedelanol and beta-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.