Alkaloid constituents from Uncaria rhynchophylla and their anti-inflammatory activity

The chemical constituents from Uncaria rhynchophylla were isolated and purefied by column chromatography on silica gel, aluminum oxide, Sephadex LH-20 and HPLC. The structure of the compounds were elucidated by spectral analysis. Eighteen compounds were isolated and identified, including dihyrdocorynantheine ( 1 ), isocorynantheidine ( 2 ), hirsutine ( 3 ), corynantheine ( 4 ), hirsuteine ( 5 ), geissoschizine methyl ether ( 6 ), villocarine A ( 7 ), 16R-E-isositsirikine ( 8 ), sitsirikine ( 9 ), 19, 20-dihydroisositsirikine ( 10 ), hirsuteine N-oxide ( 11 ), geissoschizine N-oxide methyl ether ( 12 ), corynoxine ( 13 ), isorhynchophyllic acid ( 14 ), isocorynoxeine ( 15 ), corynoxine B ( 16 ), corynoxeine ( 17 ), akuammigine ( 18 ). Compound 2, 7, 8 and 10 were first isolated from Uncaria rhynchophylla. And compound 13 showed modest anti-inflammatory activity.