Does the Ethnomedicinal Use of Pequi Oil for the Treatment of Infections Reveal its Antifungal Potential?

Abstract

In Brazil, the use of medicinal plants has been on the rise over the years, especially as an alternative for the treatment of diseases caused by fungal infections. Fungal infections have become a major public health problem, primarily due to the indiscriminate and prolonged use of antibiotics. In this context, among the various species of the Brazilian flora, an endemic species stands out, Caryocar coriaceum, popularly known as "pequi," is widely used in nutrition and is also employed by the population for medicinal purposes to treat infectious diseases. Thus, this study aims to evaluate the chemical composition, antifungal action of the medicinal oil from Caryocar coriaceum, test the combined effect with the drug Fluconazole, and finally determine the chemical constituents present in the oil of pequi fruits. Initially, the fruits of this species were subjected to boiling in broth microdilution, and the combined effect with Fluconazole was assessed at sub-inhibitory concentrations (1/8 MIC), followed by spectrophotometric readings used to determine the IC50. The C. coriaceum species is composed of four fatty acids, of which two were more prevalent, oleic acid and palmitic acid. The fixed oil showed low antifungal activity when evaluated individually for Candida albicans and Candida tropicalis strains, with IC50 values of 593.8 μg/mL, exhibiting greater modification for the standard drug with IC50 values for C. albicans at 16.07 μg/mL and C. tropicalis at 4.77 μg/mL. However, for the Candida krusei strain, the fixed oil exhibited more potent antifungal activity than Fluconazole at concentrations of 32 μg/mL and 64 μg/mL, while Fluconazole had intensified activity at concentrations from 2 μg/mL up to 128 μg/mL. Regarding the potentiating action for Candida albicans, Candida tropicalis and Candida krusei strains, the oil associated with Fluconazole enhanced the antifungal effect with IC50 values of 0.02792 μg/mL for C. albicans, 0.09903 μg/mL for C. tropicalis, and 15.15 μg/mL for C. krusei. Thus, the oil contains promising compounds in its composition for the development of medications to treat infectious diseases.