QM-HiFSA-Aided Structure Determination of Succinilenes A-D, New Triene Polyols from a Marine-Derived Streptomyces sp.

Based on profiles of secondary metabolites produced by marine bacteria obtained using LC/MS, succinilenes A-D (-), new triene polyols, were discovered from a culture of a strain SAK1, which was collected in the southern area of Jeju Island, Republic of Korea. The gross structures of - were primarily determined through analysis of NMR spectra. The double bond geometries of the succinilenes, which could not be established from conventional ¹H NMR spectra because of the highly overlapped olefinic signals, were successfully deciphered using the recently developed quantum-mechanics-driven ¹H iterative full spin analysis (QM-HiFSA). Succinilenes A-C (-) displayed inhibitory effects against lipopolysaccharide (LPS)-induced nitric oxide (NO) production, indicating their anti-inflammatory significance. These three compounds (-) commonly bear a succinic acid moiety, although succinilene D (), which did not inhibit NO production, does not have this moiety in its structure. The absolute configurations of succinilenes A-D (-) were established through -based configuration analysis, the modified Mosher's method following methanolysis, and CD spectral analysis.