Bioactive Steroids with Structural Diversity from the South China Sea Soft Coral sp. and Sponge sp.

A chemical investigation of the soft coral sp. and the sponge sp. from the South China Sea led to the isolation of five steroids, including two new compounds ( and ) and one known natural product (). Compounds - were derived from the soft coral sp., while and were obtained from the sponge sp. The structures of these compounds were determined by extensive spectroscopic analysis, the time-dependent density functional theory-electronic circular dichroism (TDDFT-ECD) calculation method, and comparison with the spectral data previously reported in the literature. The antibacterial and anti-inflammatory activities of isolated compounds were evaluated in vitro. Compounds -, , and exhibited weak antibacterial activity against vancomycin-resistant G1, KSP28, FP2244, FP5245, and ZJ028. Moreover, compound showed significant anti-inflammatory activity by inhibiting lipopolysaccharide (LPS)-induced NO production in RAW 264.7 cells, with an IC value of 13.48 μM.