Effects of Capsaicin on the Growth and Virulence Factors of Aspergillus fumigatus

Introduction: Emerging drug-resistant fungal pathogens and the limitations of current antifungal therapies necessitate the development of alternative therapeutic strategies. This study aimed to investigate the effects of capsaicin on the growth and virulence factors of Aspergillus fumigatus AF۲۹۳. Methods: The impact of capsaicin on fungal growth, ergosterol content, and gene expression was evaluated at concentrations up to ۲۵ μg/mL, and on biofilm formation at concentrations up to ۱۰۰ μg/mL. Expression levels of the PLB۱, PLB۲, PLD۱, and PLD۲ genes were quantified using quantitative real-time PCR (qRT-PCR). Results: Capsaicin exhibited dose-dependent antifungal activity, inhibiting fungal growth (۱۵.۳۳–۸۹.۷۸%) and reducing ergosterol content (۴۲.۳۵–۸۲.۵۹%) at concentrations of ۳.۱۲۵–۲۵ μg/mL. The half-maximal inhibitory concentration (IC₅₀) for fungal growth was estimated to be between ۶.۲۵ and ۱۲.۵ μg/mL. At the highest concentration tested (۱۰۰ μg/mL), biofilm formation was significantly suppressed by ۸۸.۳۴%. PLB۱ and PLB۲ gene expression was downregulated in a dose-dependent manner, with maximal reductions of ۵۶% and ۶۳%, respectively, at ۲۵ μg/mL. In addition, the expression of PLD۱ and PLD۲ genes decreased by ۳۱.۴% and ۴۸.۱۳%, respectively, at the highest tested concentration. Conclusion: Capsaicin demonstrates potent antifungal activity against A. fumigatus AF۲۹۳ by inhibiting fungal growth, disrupting ergosterol biosynthesis, and reducing key virulence factors, including biofilm formation as well as PLB and PLD genes expression. These findings suggest that capsaicin is a promising lead compound for antifungal drug development.

کلیدواژه ها:

Antifungal resistance ، Aspergillus fumigatus AF۲۹۳ ، Biofilm ، Capsaicin ، Ergosterol ، Phospholipase B ، Virulence factors