Antifungal activity of cinnamic acid and benzoic acid esters against Candida albicans strains

Candida albicans is an important opportunistic fungal pathogen capable of provoking infection in humans. In the present study, we evaluated the antifungal effect of 23 ester derivatives of the cinnamic and benzoic acids against 3 C. albicans strains (ATCC-76645, LM-106 and LM-23), as well as discuss their Structure-Activity Relationship (SAR). The antifungal assay results revealed that the screened compounds exhibited different levels of activity depending on structural variation. Among the ester analogues, methyl caffeate (5) and methyl 2-nitrocinnamate (10) were the analogues that presented the best antifungal effect against all C. albicans strains, presenting the same MIC values (MIC = 128 μg/mL), followed by methyl biphenyl-2-carboxylate (21) (MIC = 128, 128 and 256 μg/mL for C. albicans LM-106, LM-23, and ATCC-76645, respectively). Our results suggest that certain molecular characteristics are important for the antifungal action.