Structural Elucidation and Structure–Anti-inflammatory Activity Relationships of Cembranoids from Cultured Soft Corals Sinularia sandensis and Sinularia flexibilis

Abstract

New cembranoids 4-carbomethoxyl-10-epigyrosanoldie E (1), 7-acetylsinumaximol B (2), diepoxycembrene B (6), dihydromanaarenolide I (8), and isosinulaflexiolide K (9), along with 11 known related metabolites, were isolated from cultured soft corals Sinularia sandensis and Sinularia flexibilis. The structures were elucidated by means of infrared, mass spectrometry, and nuclear magnetic resonance techniques, and the absolute configurations of 1, 4, 9, and 15 were further confirmed by single-crystal X-ray diffraction analysis. The absolute configurations of these coral metabolites and comparison with known analogues showed that one hypothesis (that cembrane diterpenes possessing an absolute configuration of an isopropyl group at C1 obtained from Alcyonacean soft corals belong to the α series, whereas analogues isolated from Gorgonacean corals belong to the β series) is not applicable for a small number of cembranoids. An in vitro anti-inflammatory study using LPS-stimulated macrophage-like cell line RAW 264.7 revealed that compounds 9-14 significantly suppressed the accumulation of pro-inflammatory proteins, iNOS and COX-2. Structure-activity relationship analysis indicated that cembrane-type compounds with one seven-membered lactone moiety at C-1 are potential anti-inflammatory agents. This is the first culture system in the world that has successfully been used to farm S. sandensis.

Marine natural products

“…829 X-ray studies were used to determine the complete structural and stereochemical characterization of sarcophelegan A 1164, 825 cembranoid 1173 and isosinulaexiolide K 1177. 829 X-ray studies were also used to conrm the structures and conguration of previously reported cembranoids sarsolilide B (Sarcophyton trocheliophorum) 826,830 pukalide (Leptogorgia alba) 831 and dendronpholide F (Dendronephthya sp.) 829,832 The trivial name epoxynephthenol assigned to 1150 (ref.…”

Sinulariolide Suppresses Cell Migration and Invasion by Inhibiting Matrix Metalloproteinase-2/-9 and Urokinase through the PI3K/AKT/mTOR Signaling Pathway in Human Bladder Cancer Cells

“…Sinulariolide was prepared from the extract of cultured-type soft coral Sinularia flexibilis, following the previously published protocol [40,41] …”

Cubitanoids and Cembranoids from the Soft Coral Sinularia nanolobata

“…In some plants, cubitene was detected by gas chromatography–mass spectrometry (GC/MS) from their volatile oils [6]. In the aforementioned three sources, cubitanoids were usually found in company with cembranoids [1], which represent a large group of compounds in soft coral [7,8,9,10]. The origin of cubitanoids was speculated to be associated with the co-occurring cembranoids based on a photochemical interconversion [4].…”