%0 Generic %A Lim, Kuan-Hon %A Raja, Vijay J. %A Bradshaw, Tracey D. %A Lim, Siew-Huah %A Low, Yun-Yee %A Kam, Toh-Seok %D 2015 %T Ibogan, Tacaman, and Cytotoxic Bisindole Alkaloids from Tabernaemontana. Cononusine, an Iboga Alkaloid with Unusual Incorporation of a Pyrrolidone Moiety %U https://acs.figshare.com/articles/dataset/Ibogan_Tacaman_and_Cytotoxic_Bisindole_Alkaloids_from_i_Tabernaemontana_i_Cononusine_an_Iboga_Alkaloid_with_Unusual_Incorporation_of_a_Pyrrolidone_Moiety/2164762 %R 10.1021/acs.jnatprod.5b00117.s002 %2 https://acs.figshare.com/ndownloader/files/3798661 %K Cell cycle %K MS analyses %K HT %K Compounds 7 %K ervatensine %K Unusual Incorporation %K HCT %K KB cells %K Iboga Alkaloid %K MDA %K compounds 7 %K Pyrrolidone MoietySix %K multidrug resistance %K NMR %K Cytotoxic Bisindole Alkaloids %K IC 50 %K bisindole %K indole alkaloids %K Malayan Tabernaemontana corymbosa %K 2 μ M %K cell death %K MCF %X Six new indole alkaloids, viz., cononusine (1, a rare example of an iboga–pyrrolidone conjugate), ervaluteine (2), vincamajicine (3), tacamonidine (4), 6-oxoibogaine (5), and N4-chloromethylnorfluorocurarine chloride (6), and two new vobasinyl-iboga bisindole alkaloids, ervatensines A (7) and B (8), in addition to other known alkaloids, were isolated from the stem-bark extract of the Malayan Tabernaemontana corymbosa. The structures of these alkaloids were established on the basis of NMR and MS analyses and, in one instance (7), confirmed by X-ray diffraction analysis. Vincamajicine (3) showed appreciable activity in reversing multidrug resistance in vincristine-resistant KB cells (IC50 2.62 μM), while ervatensines A (7) and B (8) and two other known bisindoles displayed pronounced in vitro growth inhibitory activity against human KB cells (IC50 < 2 μM). Compounds 7 and 8 also showed good growth inhibitory activity against A549, MCF-7, MDA-468, HCT-116, and HT-29 cells (IC50 0.70–4.19 μM). Cell cycle and annexin V-FITC apoptosis assays indicated that compounds 7 and 8 inhibited proliferation of HCT-116 and MDA-468 cells, evoking apoptotic and necrotic cell death. %I ACS Publications