Abstract: Phytochemical investigation on the 95% ethanol extract of Uncaria lancifolia led to the isolation of 19 phenolic compounds,including epicatechin (1),catechin (2),cinchonain Ia (3),cinchonain Ib (4),cinchonain Ⅱa (5),cinchonain Ⅱb (6),procyanidin B₂ (7),procyanidin B₅ (8),procyanidin C₁ (9),hedyotol D (10),(±)-lariciresinol (11),(+)-pinoresinol (12),9-O-(Z)-feruloyllariciresinol (13),9-O-(E)-feruloyllariciresinol (14),(+)-lyoniresinol 9′-O-glucoside (15),pomegralignan (16),scopoletin (17),cleomiscosin B (18) and hymexelsin (19).This is the first reporting for the chemical constituents of U.lancifolia.All compounds were obtained from this plant for the first time.Among them,ten compounds including 7-14,16 and 19 were isolated from Uncaria genus for the first time.

Key words: Uncaria lancifolia, phenolic compounds, proanthocyanidins, lignans, coumarins