Metabolites from the Paracel Islands Soft Coral Sinularia cf. molesta

Abstract

Five new oxygenated sesquiterpenes, molestins A–D (1, 3–5) and epi-gibberodione (2), three new cyclopentenone derivatives, ent-sinulolides C, D, and F ((+)-9–(+)-11), one new butenolide derivative, ent-sinulolide H ((+)-13), and one new cembranolide, molestin E (14), together with 14 known related metabolites (6–8, (–)-9–(–)-11, (±)-12, (–)-13, 15–19) were isolated from the Paracel Islands soft coral Sinularia cf. molesta. The structures and absolute configurations were elucidated based on comprehensive spectroscopic analyses, quantum chemical calculations, and comparison with the literature data. Compound 5 is the first example of a norsesquiterpene with a de-isopropyl guaiane skeleton isolated from the genus Sinularia. Molestin E (14) exhibited cytotoxicities against HeLa and HCT-116 cell lines with IC50 values of 5.26 and 8.37 μM, respectively. Compounds 4, 5, and 8 showed significant inhibitory activities against protein tyrosine phosphatase 1B (PTP1B) with IC50 values of 218, 344, and 1.24 μM, respectively.

Chemical Diversity and Biological Activity of Secondary Metabolites from Soft Coral Genus Sinularia since 2013

“…Two 4,5-seco-africane-type sesquiterpenes, molestin A (23) and epi-gibberodione (24), and two guaiane-type sesquiterpenes, molestins B-C (25, 26), were isolated from the Paracel Islands soft coral S. cf. molesta [40]. Compound 26 displayed strong inhibitory activities against PTP1B [40].…”

“…Twelve new cembranoids sinulariols T−Z 4 (37)(38)(39)(40)(41)(42)(43)(44)(45)(46)(47) and a new capnosane diterpene sinulariol Z 5 (48) were separated from S. rigida [14], which was collected in Sanya Bay, Hainan Island of China. Compound 43 displayed dose-dependency and showed significant inhibition against the larval settlement of the barnacle Ba.…”

“…A new furanocembranolide molestin E (102) was isolated from the Paracel Islands soft coral S. cf. molesta [40], and it exhibited cytotoxicities against HeLa and HCT-116 cell lines [40].…”

“…The norhumulene was suggested to be the precursor. Molestins D (147) was the first example of a norsesquiterpene with a deisopropyl guaiane skeleton isolated from the genus Sinularia [40], and it showed significant inhibitory activities against protein tyrosine phosphatase 1B (PTP1B). The norditerpenes from S. sp.…”

“…Three new cyclopentenone derivatives, ent-sinulolides C, D, and F (230-232) were isolated from the Paracel Islands soft coral S. cf. molesta [40]. Their cytotoxic (against HeLa,…”