Alkaloids from Corydalis nobilis (L.) PERS. and C. intermedia (L.) MÉRAT

Abstract

Rhizomes of Corydalis nobilis (L.) PERS. (3% of alkaloids) contain (+)-tetrahydropalmatine, (+)-bicuculline and (+)-corytuberine as the main constituents of the tertiary alkaloid fraction. Protopine, (+)-corypalmine and (+)-stylopine, which also belong to the dominant alkaloids, were isolated in lesser amounts. As minor alkaloids were isolated (±)-tetrahydropalmatine, (+)-corydaline, allocryptopine, cryptopine, (-)-scoulerine, (+)-adlumidine, (+)-sinactine, (±)-corlumine, isoboldine, (+)-corybulbine, (±)-stylopine and (-)-isocorypalmine. The fraction of quaternary protoberberine alkaloids afforded coptisine dehydrocorydaline, palmatine, corysamine jatrorrhizine and cis-N-methylstylopinium hydroxide. Aobamidine (Z-adlumidiceine enol lactone), isolated as the principal alkaloid of aerial parts (0.3% of alkaloids), is obviously an artifact arising from bicuculline N-metho salt during the isolation process. Further dominant alkaloids of the tertiary fraction were adlumidine, bicuculline, protopine, (±)-tetrahydropalmatine and (±)-corlumine; as minor alkaloids were isolated corytuberine, scoulerine, corypalmine, cryptopine, isocorypalmine, corybulbine, (+)-corydalizine, and unidentified alkaloids CN 1 (C23H25NO5, m.p. 211 °C) and CN 2 (m.p. 261 °C). Quaternary protoberberine fraction afforded coptisine and palmatine. Nineteen of the mentioned alkaloids were isolated from this species for the first time. Tubers of C. intermedia (L.) MÉRAT (0.70% of alkaloids) afforded protopine, tetrahydropalmatine and corydaline as the main alkaloids and allocryptopine, canadine stylopine, palmatine, dehydrocorydaline, berberine, coptisine as minor alkaloids, together with traces of bicuculline and magnoflorine. Dominant alkaloids of the aerial part (0.73% of alkaloids) were bicuculline, bulbocapnine, protopine, stylopine and an unidentified phenolic base, m.p. 258 °C. Isoboldine, scoulerine, allocryptopine, corydaline, canadine, coptisine, palmatine and berberine were identified as the minor alkaloids.