Studies on the constituents of Picrasma quassioides Bennet. I. On the alkaloidal constituents.

1-Acetyl-β-carboline (I), 4, 8-dimethoxy-1-ethyl-β-carboline (II), and three new alkaloids, 4, 8-dimethoxy-1-(2-methoxyethyl)-β-carboline (III), β-carbolin-1-yl 4, 8-dimethoxy-β-carbolin-1-yl-ethyl ketone (IV) and 3-methylcanthin-2, 6-dione (V), were isolated from the root of Picrasma quassioides BENNET (Simaroubaceae). The structures were elucidated on the basis of spectroscopic studies and chemical evidence.