Abstract
As a continuation of the work on EtOAc fraction of the Indonesian sponge Acanthostrongylophora ingens, 2 new alkaloids: one pyrimidine-β-carboline alkaloid named ingenine A (2) and one pyrimidine-γ-carboline alkaloid named ingenine B (3), along with annomontine (1) were isolated. Their structures were unambiguously established on the basis of NMR spectroscopy ((1) H, (13)C, (1) H-(1) H COSY, HMQC, and HMBC) and mass spectral data. This is the first report of isolation pyrimidine-γ-carboline alkaloid from natural source. Compounds 1 and 3 showed pronounced cytotoxicity against the murine lymphoma L5178Y cancer cell line with ED50 7.8 and 9.1 μg/mL respectively, while compound 2 showed weak activity.