Coscinium fenestratum furnished a new minor alkaloid, 12,13-dihydro-8-oxo-berberine, [5,6,13,13a-tetrahydro-9,10-dimethoxydibenzo(a,g)1,3-benzodioxolo(5,6a)quinalizine-8-one], as well as berberine, oxyberberine, tetrahydroberberine (canadine), sitosterol and stigmasterol. © 1989.