Bioactive indole alkaloids from insect derived endophytic Aspergillus lentulus.

As part of our program to discover new bioactive agents from endophytic fungi, three new indole alkaloids (1-2, 4) along with twelve known compounds were isolated from an inset derived endophytic strain Aspergillus lentulus. Their structures were determined by comprehensive spectroscopic analyses of 1D/2D NMR and HR-ESI-MS data. The absolute configurations were confirmed by ECD calculation using Time-dependent Density functional theory (TD-DFT) at the B3LYP/6-31 + g (d, p) level and Rh2(OCOCF3)4-induced ECD experiments. Compounds 2, 4, 5, 13 and 15 exhibited moderate cytotoxic effects on A549 cell line with IC50 in the range of 17.92-48.29 μM. Compounds 1, 2 and 13-15 displayed the anti-bacterial activity against Xanthomonas oryzae pv. oryzae and Xanthomonas oryzae pv. oryzicola with MIC values ranging from 25 to 100 μg/mL.