Chemical investigation of the ethyl acetate extract of the endophytic fungus Penicillium thiomii isolated from the medicinal plant Terminalia chebula Retz and cultured on potato dextrose agar led to the isolation of one new compound named terminatone (2) along with three known compounds namely, ergosterol (1), 4-hydroxy benzaldehyde (3) and 4-hydroxy-hexadec-6-enoic acid methyl ester (4). The structures of the isolated compounds were determined by spectroscopic techniques i.e. UV, IR, 1D & 2D NMR, and by comparison with the literature. The crude ethyl acetate extract and three column fractions were evaluated for antimicrobial activity against a wide range of Gram-positive and Gram-negative bacteria and fungi, general toxicity and antioxidant activity by disc diffusion method, brine shrimp lethality and free radical scavenging activities, respectively. Low activities were observed in all cases.
