Marinisporolides, Polyene-Polyol Macrolides from a Marine Actinomycete of the New Genus Marinispora

Abstract

Two new polyene macrolides, marinisporolides A and B (1, 2), were isolated from the saline culture of the marine actinomycete, strain CNQ-140, identified as a member of the new marine genus “Marinispora.” The marinisporolides are 34 membered macrolides composed of a conjugated pentaene and several pairs of 1,3-dihydroxyl functionalities. Marinisporolide A (1) contains a bicyclic spiro-bis-tetrahydropyran ketal functionality, while marinisporolide B (2) is the corresponding hemiketal. The structures of these new compounds were assigned by combined spectral and chemical methods including extensive 2D NMR experiments and correlations of 13C NMR data with Kishi’s Universal NMR Database. Chemical modifications, including methanolysis, acetonide formation, and application of the modified Mosher method, provided the full stereostructures of these molecules. Three additional macrolides, marinisporolides C–E (3–5), which are olefin geometric isomers of marinisporolide A (1), were also isolated and their structures defined. Under room light, marinisporolides A and B readily photoisomerize to C–E indicating that they are most likely produced by photochemical conversion during the cultivation or isolation procedures. Although polyenes, marinisporolides A (1) and B (2) showed weak to no antifungal activity against Candida albicans.

Marine natural products

“…67 Culture of Saccharomonospora sp. Marinisporolides A 1 and B 2 are polyene macrolides isolated from culture of an actinomycete from the new genus Marinispora [sediment, (La Jolla, California)].…”

Marine natural products

“…120,121 The rst synthesis of fradcarbazole 122 was by semi-synthesis 123 from staurosporine. 124 Also successfully synthesised were the nitrosporeusines, 125,126 jiolide A, 127,128 marinisporolide 129,130 and splenocin B. 131,132 A new route to isoquinolines was developed for the synthesis of mansouramycin 133,134 and a total synthesis and full stereochemical assignments have been completed for heronapyrroles A 168 and B 169.…”

Polyene macrolide biosynthesis in streptomycetes and related bacteria: recent advances from genome sequencing and experimental studies

“…CHQ-64 revealed part of a polyene PKS (Che et al, 2015). Marinosporus strain CNQ-140 produces the pentaenes marinisporolides A and B (Kwon et al, 2009). Polyene-polyols undergo spontaneous trans-cis isomerisation after isolation.…”