Gallic acid triphenylphosphonium derivatives TPP+-C10 and TPP+-C12 inhibit mitochondrial function in Candida albicans exerting antifungal and antibiofilm effects

To evaluate the antifungal and antibiofilm activity of gallic acid derivatives TPP+-C10 and TPP+-C12 and their effects on mitochondrial function on two C. albicans reference strains (ATCC 90029 and ATCC 10231). First, we determined minimal inhibitory concentration using a microdilution assay. Both compounds exerted antifungal effects, and their minimal inhibitory concentrations (MICs) ranged from 3.9 to 13 μM, with no statistically significant differences between them (P > 0.05, t-test). These concentrations served as references for following assays. Subsequently, we measured oxygen consumption with a Clark electrode. Our observations revealed that both drugs inhibited oxygen consumption in both strains with TPP+-C12 exerting a more pronounced inhibitory effect. We then employed flow cytometry with TMRE as a probe to assess mitochondrial membrane potential. For each strain assayed, the compounds induced a decay in transmembrane potential by 75% to 90% compared to the control condition (P