Antibacterial, antifungal and antiprotozoal activities of fungal communities present in different substrates from Antarctica

Abstract

Antarctica is a pristine and extreme environment that represents a unique opportunity for taxonomic, ecological and biotechnological studies of the microorganisms. In the present work, the fungal communities of rhizosphere soil of Deschampsia antarctica, soil, ornithogenic soil, marine and lake sediments in the Antarctic Peninsula were characterized as well as their capability to produce bioactive compounds. One hundred fungal isolates were recovered and identified by molecular analysis in 35 different taxa of 20 genera. Pseudogymnoascus sp. 1 and 3, Penicillium sp., Peniophora sp. and Mortierella alpina were the most frequent taxa identified. All isolates were cultured to produce ethanolic extracts, which were assayed against different target organisms to detect antimicrobial (against Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Candida albicans, Candida krusei, Cladosporium sphaerospermum and Paracoccidioides brasiliensis), cytotoxic (against breast MCF-7 and renal TK-10 human tumoral cells) and antiprotozoal (against Leishmania amazonensis and Trypanosoma cruzi) activities. Among the three human pathogenic fungal species, 20 extracts showed moderate to high and selective antifungal activity against P. brasiliensis. The extract of Purpureocillium lilacinum displayed high trypanocidal, antifungal and antibacterial activities, but with moderate toxicity over normal cells. Proton nuclear magnetic resonance (1H NMR) spectral analysis indicated the presence of compounds containing a highly functionalized aromatic ring system. Our results suggest that the Antarctic ecosystems represent an interesting habitat for the isolation and characterization of fungal taxa capable to producing bioactive compounds. The fungus P. lilacinum showed strong trypanocidal and antimicrobial activities with moderate toxicity over normal cells, which might be used as scaffold for the development of new drugs.