Voagafries A-E, undescribed indole alkaloids with anti-glioma activity from Voacanga africana.

Voagafries A-E, five undescribed monoterpenoid indole alkaloids (MIAs), were isolated from the stem bark of Voacanga africana. Voagafrie A (1) has a unique 6/5/5/6/6 spiral ring skeleton with an indolone-fused 9-oxo-3-aza-tricyclo[6,3,1,0]-12-alkane-10-carbonyllactone. Voagafrie B (2) is a rare 5,6-seco diazine scaffold, whereas voagafrie C (3) possesses an octahydropyrrolo[2,3-b] pyrrole-fused 2,8-diazabicyclo[3.

Spirooxindol alkaloids from Voacanga africana: Targeting biofilm of MBLs producing Escherichia coli.

Seven rarely spirooxindole alkaloids, voagafricines A-G (1-7) were isolated from the stem barks of Voacanga africana. Their structures were unambiguously elucidated by comprehensive spectroscopic data and electronic circular dichroism (ECD) analyses. 1 and 2 possess a unique indoleone system in conjugation with a 3,4'-decahydroquinoline spiral ring originating from seco-quinolhiddin core of the precursor, furthermore 1 undergo decarburization formed a novel C-3-nor monoterpenoid indole.