Roussoella species are well recorded from both monocotyledons and dicotyledons. As part of a research program to discover biologically active compounds from plant-associated Dothideomycetes in Thailand, the strain Roussoella sp. (MFLUCC 17-2059), which represents an undescribed species, was isolated from Clematis subumbellata Kurz, fermented in yeast-malt medium and explored for its secondary metabolite production. Bioassay-guided fractionation of the crude extract yielded the new abscisic acid derivative, roussoellenic acid (1), along with pestabacillin B (2), a related congener, and the cyclodipeptide, cyclo(S-Pro-S-Ile) (3). The structure of 1 was determined by 2D NMR spectroscopy and HR-ESIMS data analysis. Compounds 1 and 2 showed inhibitory activity on biofilm formation by Staphylococcus aureus. The biofilmformation of S. aureus was reduced to 34%at 16 ug/mL by roussoellenic acid (1), while pestabacillin B (2) only showed 36% inhibition at 256 ug/mL. In addition, compound 1 also had weak cytotoxic effects on L929 murine fibroblasts and human KB3-1 cancer cells.
Phukhamsakda C, Macabeo APG, Yuyama KT, Hyde KD, Stadler M. Biofilm Inhibitory Abscisic Acid Derivatives from the Plant-Associated Dothideomycete Fungus, Roussoella sp. Molecules. 2018 Aug 30;23(9). pii: E2190. doi: 10.3390/molecules23092190.
Keywords: biofilm inhibitory abscisic acid derivatives, plant-associated dothideomycete fungus, Roussoella sp, Clematis subumbellata Kurz, roussoellenic acid, pestabacillin B.
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