Antifungal efficacy of pyrolysis-derived bio-oil aqueous phases from Tropical plant biomass against Candida auris

The emerging fungal pathogen C. auris has recently been recognized as a global threat due to its ability to cause nosocomial and invasive candidemia with high mortality rates. C. auris has been widely reported for its multidrug resistance to antifungals, further complicating its clinical management. In this context, there is an urgent need for the research and development of more efficient alternatives for environmental control, disinfection, and treatment of C. auris. In this study, the antifungal properties of bio-oil aqueous phases (BOAP) derived from the pyrolysis of Cocos nucifera (coconut), Syagrus coronata (licuri), and Terminalia catappa (almond), with traditional antimicrobial efficiency, were evaluated against C. auris., All three BOAPs formulations exhibited remarkable antifungal activity, particularly the licuri BOAP I, with minimum inhibitory concentration (MIC) values ranging from 0.035 to 0.56 mg/mL, demonstrating higher efficacy. We have also evaluated the antifungal activity of volatile compounds in BOAPs, with licuri BOAP I showing the most significant inhibition halos in volatilization tests. Mass spectrometry analysis identified phenolic compounds, ketones, and aldehydes in the licuri BOAP I, with sequential organic solvent extractions further isolating active antifungal fractions. Chloroform-extractable compounds of licuri BOAP displayed the most potent antifungal activity, with MIC values of 0.14 mg/mL. In conclusion, our findings indicate the potential of bio-oils as natural antifungals, particularly the licuri-derived extracts, which could be further developed into effective treatments against resistant fungi. Furthermore, the in vivo efficacy of volatile and water-soluble active compounds could be assessed upon optimization of the extraction processes, thereby providing more sustainable and environment-friendly antifungal strategies.