Quinolizidine alkaloids from Sophora velutina subsp. zimbabweensis (Fabaceae: Sophoreae).

Three novel quinolizidine alkaloids, N-methylenehydroxycytisine (1), 6,7-dihydroxylupanine (2), and velutinine (3) have been isolated from the fruits and pods (1 and 2) and stem bark (3) of Sophora velutina subsp. zimbabweensis along with the known quinolizidine alkaloids, 7-hydroxylupanine (4), thermopsine (5), N-methylcytisine (6), cytisine (7), an aromatic ester, methyl-3-(3',4'-dimethoxyphenyl)-2-propenoate (8) and the triterpenoids, lup-20(29)-ene-3beta-ol (9) and 12-oleanen-3-one (10). Compounds 6 and 10 showed good antibacterial activity against E. faecalis, with MIC values of 20.8 and 10.9 microg mL(-1), respectively. The other compounds tested exhibited low to moderate antibacterial activity.