Abstract

Chromatographic fractionation of the antileishmanial extract obtained from fermentation of the endophytic fungus Penicillium citrinum, isolated from leaves of Ageratum myriadenia, yielded three diketopiperazine alkaloids; cyclo(L-Pro-L-Leu) (1), cyclo-(L-Pro-L-Phe) (2) and tryprostatin B (3). The structures of these compounds were established on the basis of spectroscopic methods and comparison with the literature. Compounds 1 and 2 were active against both amastigote-like forms of Leishmania (Leishmania) amazonensis and intracelular amastigotes of L. (Leishmania) infantum with approximately 50% of parasite growth inhibition at 100 μM. None of the compounds were considered toxic against human leukemia monocyte cell line (THP-1) at 100 μM. It is the first report about isolation of these diketopiperazines from P. citrinum and their antileishmanial potential against L. (L.) infantum.

Key words: Microfungi, natural products, in vitro, Leishmania, amphotericin B, cytotoxic activity.