Secondary metabolite chemistry of the marine-derived fungus Massarina sp., strain CNT-016

Abstract

Chemical investigation of the culture broth extracts of the marine-derived fungus Massarina sp. (strain CNT-016) has yielded two secondary metabolites, spiromassaritone (1) and massariphenone (2), as well as the previously reported fungal metabolites 6-epi-5'-hydroxy-mycosporulone (3) and enalin A (4). The structures of these compounds were established by a variety of one- and two-dimensional NMR experiments, while the relative configuration of spiromassaritone (1) was determined by X-ray crystallographic methods. The fungal strain was isolated as a sterile mycelium from an ocean mud sample and identified using ITS sequence analysis.

Figure 1

X-ray structure of spiromassaritone (1).

Figure 2

Stereostructures of spiromassaritone (1) and V214w (5).

Figure 3

Massarina corticola and an unknown ascomycete are closest relatives of Massarina sp. CNT-016. One of three most parsimonious trees is illustrated (tree length: 1707 steps). Support values by the branches are from parsimony, likelihood and Bayesian analyses in that order for branches of interest in this study. Otherwise parsimony support percentages above 70% are given. Well-supported branches and taxa of interest in this study are in bold, Massarina sp. CNT-016 is underlined. Massarina sp. CNT-016 groups in clade 1 (Liew et al. 2002) with high support in all analyses, and is the closest relative of M. corticola and an uncultured ascomycete with 94, 89 and 100 % support. See Liew et al. (2002) for GenBank accession numbers not included here.