Antarctic Fungi as a Source of Alternative Antifungal Compounds: Bioactive Metabolites from South Shetland Islands Fungi with Activity Against Candida Species

The emergence of drug-resistant Candida species has intensified efforts to discover novel bioactive compounds. Antarctic environments harbor psychrophilic microorganisms that produce unique secondary metabolites adapted to extreme conditions, making them valuable natural resources for drug discovery. During the 2020 Antarctic Scientific Expedition, we collected 19 sediment samples from the South Shetland Islands and isolated 14 fungal strains belonging to Cladosporium, Oidiodendron, Penicillium, Pseudeurotium, and Pseudogymnoascus genera. Total organic extracts obtained from 21-day cultures were evaluated for antimicrobial activity against pathogenic yeasts and bacteria. Oidiodendron sp. (ECA57-20) and Pseudogymnoascus sp. (ECA57-61) demonstrated strong anti-Candida activity with minimum inhibitory concentrations ranging from 7.81 to 62.5 µg/mL against C. albicans, Pichia kudriavzevii (C. krusei), C. tropicalis, Nakaseomyces glabratus (C. glabrata), and Clavispora lusitaniae (C. lusitaniae). GC-MS (gas chromatography mass spectrometry) metabolomic profiling suggests a broad diversity of secondary metabolites across active strains, which may contribute to the observed biological activities. These findings support the potential of Antarctic fungi as sources of alternative antifungal agents.