Leishmanicidal, cytotoxic, antimicrobial and enzymatic activities of Diaporthe species, a mangrove-isolated endophytic fungus

This study evaluated the biotechnological potential of the endophytic fungus Diaporthe species, which is isolated from Brazilian mangroves. In vitro studies have investigated the antimicrobial activity of Diaporthe spp. against human pathogens, such as Escherichia coli, Staphylococcus aureus, Salmonella enteritidis, and Candida albicans, as well as phytopathogenic fungi, such as Colletotrichum species, Ceratocystis paradoxa, Fusarium oxysporum, Phythophthora sojae and Rhizopus microspores. Additionally, the enzyme production and leishmanicidal and cytotoxic activities of Diaporthe spp. were tested. Minimal inhibitory concentrations (MICs) of the crude extract of Diaporthe spp. 94 ranged from 756 to 949 µg.mL-1 (MIC50) and from 3.094 to 7.082 μg.mL-1 (MIC90); the antagonism index (AI) ranged from 20 to 62% with type A interactions (“deadlock” with mycelial contact). An assay to detect enzyme production showed that this endophytic fungus produced the enzyme cellulase. The crude extract of Diaporthe spp. also demonstrated activity against the promastigote form of Leishmania infantum chagasi, exhibiting 90% cell death at 6.000 and 10.000 µg.mL-1 and 80% cell death at 4.000 µg.mL-1. Cytotoxicity tests on cultured human skin fibroblasts (the HFF-1 cell line) indicated cell viability of between 73 and 55% at 4.000 to 10.000 μg.mL-1 at 24 h; between 69 and 56% at 4.000 to 8.000 μg.mL-1 for 48 h, and 59% at 4.000 to 6.000 μg.mL-1 for 72 h.   Key words: Diaporthe species, endophytic fungus, leishmanicidal activities, cytotoxic activities, antimicrobial activities, enzymatic activities.