Fungicide Xylaria sp. BCC 1067 extract induces reactive oxygen species and activates multidrug resistance system in Saccharomyces cerevisiae

Aim: To investigate antifungal potential of Xylaria sp. BIOTEC culture collection (BCC) 1067 extract against the model yeast Saccharomyces cerevisiae. Materials & methods: Antifungal property of extract, reactive oxygen species levels and cell survival were determined, using selected deletion strains. Results: Extract showed promising antifungal effect with minimal inhibitory concentration 100 and minimal fungicidal concentration of 500 and 1000 mg/l, respectively. Strong synergy was observed with fractional inhibitory concentration index value of 0.185 for the combination of 60.0 and 0.5 mg/l of extract and ketoconazole, respectively. Extract-induced intracellular reactive oxygen species levels in some oxidant-prone strains and mediated plasma membrane rupture. Antioxidant regulator Yap1, efflux transporter Pdr5 and ascorbate were pivotal to protect S. cerevisiae from extract cytotoxicity. Conclusion: Xylaria sp. BCC 1067 extract is a potentially valuable source of novel antifungals.