Two alkaloids, canthin-6-one 9-O-beta-glucopyranoside and 7-hydroxy-beta-carboline 1-propionic acid, were isolated from the roots of Eurcoma harmandiana together with the five known canthin-6-one alkaloids, 9-hydroxycanthin-6-one, 9-methoxycanthin-6-one, 9,10-dimethoxycanthin-6-one, canthin-6-one
By bioactivity-directed fractionation, five cytotoxic constituents have been characterized from the roots of Eurycoma longifolia collected in Kalimantan, Indonesia. Four canthin-6-one alkaloids, namely, 9-methoxycanthin-6-one, 9-methoxycanthin-6-one-N-oxide, 9-hydroxycanthin-6-one, and