1H NMR-Based Isolation of Anti-Inflammatory 9,11-Secosteroids from the Octocoral Sinularia leptoclados.

Octocoral Sinularia leptoclados has been identified as a source of bioactive 9,11-secosteroids. This study adopted a targeted isolation approach to the discovery and analysis of five 9,11-secosteroids, including two novel compounds named sinleptosterols A (1) and B (2) as well as five known analogues (8αH-3ß,11-dihydroxy-24-methylene-9,11-secocholest-5-en-9-one (3), 8ßH-3ß,11-dihydroxy-24-methylene-9,11-secocholest-5-en-9-one (4), leptosterol A (5), (24S)-3ß,11-dihydroxy-24-methyl-9,11-secocholest-5-en-9-one (6), and 3ß,11-dihydroxy-9,11-secogorgost-5-en-9-one (7)) in terms of 1H-NMR patterns and potency against neutrophilic inflammation. The structure of secosteroids 1 and 2 was deduced from general spectroscopic analysis and an examination of NMR spectra. Among the above-mentioned isolates, compound 4 had the most pronounced effect in inhibiting elastase release and superoxide anion generation, with the IC50 values of 2.96 and 1.63 µM, respectively.

Cytotoxic Steroids from the Vietnamese Soft Coral Sinularia leptoclados.

Fifteen steroids, including two new compounds, leptosteroid (1) and 5,6ß-epoxygorgosterol (2), were isolated and structurally elucidated from the Vietnamese soft coral Sinularia leptoclados. Their cytotoxic effect against a panel of eight human cancer cell lines was evaluated using sulforhodamine B (SRB) method. Significant cytotoxicity against hepatoma cancer (HepG2, IC50=21.13±0.70 µM) and colon adenocarcinoma (SW480, IC50=28.65±1.53 µM) cell lines were observed for 1 and against acute leukemia (HL-60, IC50=20.53±2.26 µM) and SW480 (IC50=26.61±1.59 µM) for ergost-5-en-3ß,7ß-diol (8). In addition, 3ß,7ß-dihydroxyergosta-5,24(28)-diene (13) showed significant cytotoxic activity on all tested cell lines with IC50 values ranging from 13.45±1.81 to 29.01±3.21 µM.