Aiming to identify new sources of bioactive secondary metabolites, we isolated 82 endophytic fungi from stems and barks of the native Brazilian tree
Caesalpinia echinata
Lam. (Fabaceae). We tested their ethyl acetate extracts in several in vitro assays. The organic extracts from three isolates showed antibacterial activity against
Staphylococcus aureus
and
Escherichia coli
[minimal inhibitory concentration (MIC) 32-64 μg/mL]. One isolate inhibited the growth of
Salmonella typhimurium
(MIC 64 μg/mL) and two isolates inhibited the growth of
Klebsiella oxytoca
(MIC 64 μg/mL),
Candida albicans
and
Candida tropicalis
(MIC 64-128 μg/mL). Fourteen extracts at a concentration of 20 μg/mL showed antitumour activities against human breast cancer and human renal cancer cells, while two isolates showed anti-tumour activities against human melanoma cancer cells. Six extracts were able to reduce the proliferation of human peripheral blood mononuclear cells, indicating some degree of selective toxicity. Four isolates were able to inhibit
Leishmania (Leishmania) amazonensis and one isolate inhibited
Trypanosoma cruzi by at least 40% at 20 μg/mL. The trypanocidal extract obtained from
Fusarium
sp. [KF611679] culture was subjected to bioguided fractionation, which revealed beauvericin as the compound responsible for the observed toxicity of
Fusarium sp. to
T. cruzi. This depsipeptide showed a half maximal inhibitory concentration of 1.9 μg/mL (2.43 μM) in a
T. cruzi cellular culture assay.
