Abstract
Two new pyrimidine-beta-carboline alkaloids, namely ingenines C (1) and D (2), along with three known compound: annomontine (3), acanthomine A (4), and 1-hydroxy-3,4-dihydronorharman (5) were isolated from the EtOAc fraction of the Indonesian sponge Acanthostrongylophora ingens. Their structures were unambiguously established on the basis of UV, IR, HRESIMS, 1D and 2D NMR experiments, in addition to comparison with literature data. beta-Carboline alkaloids with a 2-aminopyrimidine moiety as found in ingenines are very rarely encountered in nature. The new compounds were tested for their cytotoxic activity against different cancer cell lines. Compounds 1 and 2 exhibited cytotoxic activities towards MCF7 and HCT116 with IC50 values of 4.33 and 6.05 and 2.90 and 3.35 mM, respectively compared to doxorubicin. (C) 2016 Phytochemical Society of Europe. Published by Elsevier Ltd. All rights reserved.