Anti‐ Candida Flavonoid Leads: Mechanistic Evaluation and Early Safety Assessment

Abstract

Candida infections remain difficult to treat because of antifungal resistance, toxicity, and suboptimal pharmacokinetics. This study comparatively evaluated fourteen structurally diverse flavonoids against Candida albicans , Candida glabrata , and Candida krusei to identify structure–activity, mechanistic, and early selectivity relationships rather than to rediscover previously reported activities of individual flavonoids. Antifungal activity was assessed by minimum inhibitory concentration (MIC), minimum fungicidal concentration (MFC), and time‐kill assays. Mechanistic evaluation included concentration‐dependent ergosterol depletion and a lanosterol 14α‐demethylase (CYP51)‐associated sterol readout, supported by validated molecular docking, pharmacophore modelling, molecular dynamics, and density functional theory calculations. Brine shrimp lethality, cytotoxicity in HepG2, HK‐2, and Vero cells, and in silico ADME/toxicity predictions provided preliminary selectivity information. Diosmin ( 3 ) and rutin ( 4 ) showed the strongest activity against C. albicans (MIC = 12.5 µM). Rutin ( 4 ) produced the strongest CYP51‐associated response (82.27%–84.75%), while diosmin ( 3 ) and rutin ( 4 ) showed docking scores of −12.15 and −11.38 kcal/mol, respectively. Rutin ( 4 ) also showed CC 50 values of 500.65–800.63 µM. Overall, integrated cross‐assay analysis identified diosmin and rutin as the most consistent flavonoid leads.