The new bioactive diterpenes cyanthiwigins E-AA from the Jamaican sponge Myrmekioderma styx

Twenty-seven diterpenes, cyanthiwigins A-AA (1-27), were isolated from the Jamaican sponge Myrmekioderma styx. Cyanthiwigins E-AA (5-27) are unreported natural products and their structures were elucidated by detailed analysis of H-1, C-13, DEPT, COSY, NOESY, HMQC and HMBC NMR spectra. Cyanthiwigins are 5,6,7-tricarbocyclic diterpenes, in which the chemical shift of the beta-olefinic carbon of the cyclopentenone resonates at a low field of 195 ppm. Cyanthiwigins A (1), B (2), C (3) and D (4) were assayed against hepatitis B virus (HBV), human immunodeficiency virus (HIV-1), and Mycobacterium tuberculosis (Mtb). Cyanthiwigin C (3) exhibited activity against HBV and Mtb with an EC50 of 43 mug/mL and 50% inhibition at 6.25 mug/mL, respectively. Cyanthiwigin B (2) exhibited activity against HIV-1 with an EC50 of 42.1 muM. Cyanthiwigins A, C-F, I and Z (1, 3-6, 10, 26) are active against human primary tumor cells (IC50<18 muM) with cyanthiwigin F exhibiting the strongest activity (IC50 3.1 muM). (C) 2002 Elsevier Science Ltd. All rights reserved.