Chemical constituents of Quercus pannosa / 中草药

ABSTRACT

Objective: To study the chemical constituents of Quercus pannosa. Methods: The compounds were isolated and purified by chromatography on silica gel and RP C18 columns, and HPLC, and their structures were assigned on the basic of spectroscopic data. Results: From the ethyl acetate fraction of 95% ethanol extract from Q. pannosa, eight compounds were isolated. Among them, four were lignans and other four were triterpenoids. They were identified as rel-(7α, 8β)-3-methoxy-4', 7-epoxy-8, 3'-oxyneolignan-4, 9, 8'-triol (1), rel-(7α, 8β)-3-methoxy-4', 7-epoxy-8, 3'-oxyneolignan-4, 9, 9'-triol (2), (+)-syringaresinol (3), (8R, 8'R)-4, 4'-dihydroxy-3, 3'-dimethoxylianane-7, 7'-dione (4), ursolic acid (5), oleanolic acid (6), maslinic acid (7), and hederagenin (8). Conclusion: Compound 1 is a new lignan, named quercus pannosa-triol. The other compounds are isolated from this plant for the first time.