Two new bioactive polyketides from Curvularia trifolii, an endolichenic fungus isolated from Usnea sp., in Sri Lanka

Abstract

Two new polyketides (compounds 1 and 2) were isolated from the EtOAc extract of an endolichenic fungus, Curvularia trifolii obtained from Usnea sp. in Sri Lanka. The structures of these compounds were elucidated on the basis of spectroscopic methods (UV, IR, MS, 1D NMR and 2D NMR). The bioactivity of the compounds 1 and 2 were studied using DPPH antioxidant assays and they showed radical scavenging activity with IC50 values of 4.0 ± 2.6 and 1.3 ± 0.2 mg/mL, respectively. The radical scavenging activity of compound 2 was higher than that of compound 1 and it was comparable to BHT. Moreover, the new compounds 1 and 2 were evaluated for their anti-inflammatory activity, and only compound 2 exhibited a significant activity comparable to the standard antiinflammatory drug, aspirin. Compound 1 was evaluated for the inhibition of cell proliferation in a panel of five cancer cell lines NCI-H460, MCF-7, SF-268, PC-3M and MIA Pa Ca-2, and exhibited > 90 % inhibitory activity at 5 µg/mL with all of the above cell lines.