Effects of Carvacrol on Morphogenesis and Lipase-Associated Phenotypes in Clinical Isolates of Candida albicans
Iasmin Freitas Pimentel Pequeno, Larissa Alves da Silva, Luanna de Oliveira e Lima, Meryellem Bezerra Soares, Camila Mendes Soares, Raimundo Euzébio da Costa Neto, José Maria Barbosa Filho, Felipe Queiroga Sarmento Guerra, Guilherme Maranhão Chaves, Walicyranison Plínio da Silva RochaBackground: Candida albicans is the main etiological agent of oral candidiasis and expresses several virulence-associated traits that contribute to tissue invasion and persistence within the host. Among these, morphogenesis and hydrolytic enzyme secretion are central to fungal pathogenicity. Carvacrol, a phenolic monoterpenoid found in essential oils from aromatic plants, has demonstrated antifungal activity against Candida species, although its effects on virulence phenotypes in clinical isolates remain poorly explored. Therefore, this study investigated the effects of carvacrol on morphogenesis and lipase activity in clinical isolates of C. albicans obtained from oral candidiasis. Methods: Thirteen clinical isolates of C. albicans obtained from the oral mucosa of patients with oral candidiasis and one reference strain (ATCC 90028) were evaluated in the presence and absence of carvacrol (256 μg/mL). The effects of carvacrol on germ tube formation, morphology index, hyphal length, colony filamentation in Spider medium, and lipase activity were analyzed using phenotypic assays. Results: Carvacrol reduced germ tube formation in most of the evaluated strains and decreased the overall morphology index, indicating attenuation of filamentous morphologies. In strains that maintained hyphal growth, treatment with carvacrol significantly reduced hyphal length. In addition, colonies grown in Spider medium supplemented with carvacrol exhibited predominantly smooth morphologies, with reduced filamentous formation. Lipase activity was also inhibited in all evaluated strains in the presence of the compound. Notably, variability in phenotypic response was observed among clinical isolates, particularly in strain 97, which maintained partial filamentation under treatment conditions. Conclusions: Exposure to carvacrol was associated with alterations in morphogenesis- and lipase-associated phenotypes in clinical isolates of C. albicans under inhibitory conditions. Because the experiments were conducted using a concentration corresponding to 2× MIC, the present findings do not allow discrimination between specific modulation of virulence-associated phenotypes and indirect effects associated with growth inhibition.