Pyrrolo[2,1-a]isoquinoline and pyrrole alkaloids from Sinomenium acutum

Two pyrrolo[2,1-a]isoquinolines (1 and 2) and three pyrrole alkaloids (3-5), including three new ones, named sinopyrines A-C (1-3), were isolated from the 95% EtOH extract of the stems and rhizomes of Sinomenium acutum (Thumb.) Rehd. et Wils. The structures of the new compounds were elucidated on the basis of spectroscopic data. This is the first report of pyrrole-bearing natural compounds from the family Menispermaceae.