RESUMEN
Four new polyhydroxylated steroids plaksterols A-D (1-4), together with two known related steroids ergost-7,9(11),22-trien-3β,5α,6α-triol (5) and ergosta-6β-methoxy-7,22-diene-3β,5α-diol (6), were isolated from methanol extract of the South China Sea marine sponge Plakortis sp. Their structures were identified by spectroscopic analysis, including NMR, MS, and IR. The cytotoxicity of the polyhydroxylated steroids were evaluated, and compound 6 showed moderate inhibitory activities against K562, HL-60 and BEL-7402 cells.
RESUMEN
Structural identification of natural products is the foundation for biological activity evaluation and further targeting action research. However, exact and prompt solutions to the structures, in particular, for the stereochemical problems derived from inherent variability and complexity of natural products, have been faced with challenges. In recent years, the quantum chemistry calculation methods (ECD, VCD, 0R, NMR and others) on the basis of Gaussian software undoubtedly provide a powerful tool for the structure elucidation of complex natural products. This review summarizes some successful cases of Gaussian calculation on structure elucidation with a purpose of broadening research and applications of this method.