Evaluation of the Antifungal Activity of the Methanolic Extract of Psidium Guineense (Myrtaceae) Against Strains of the Genus Candida

Abstract

Candidiasis is the most common fungal infection of the oral cavity, and its etiological factor is the proliferation and growth of microorganisms of the genus Candida. Candida fungi make up the diverse microbiota of the oral cavity living in a harmless commensal relationship with the host and can colonise different habitats such as mucous membranes and skin. Several antifungal drugs have been used for the treatment of candidiasis, such as azole antifungals (ketoconazole, fluconazole) and polyene antifungals (nystatin, amphotericin B), however, several challenges have been observed regarding the effectiveness of drug treatment. Thus, the use of medicinal plants presents itself as a viable and promising alternative for the discovery of new phytopharmaceutical agents with great biological potential. Based on literature studies that show the physicochemical and ethnopharmacological characteristics of medicinal plant species, this research aimed to evaluate the antifungal activity of the methanolic extract of Psidium guineense (Myrtaceae). The study was carried out through in vitro assays where the methanolic extract of Psidium guineense was used as a test substance against the fungal species of Candida albicans, Candida tropicalis and Candida krusei previously identified and maintained in Sabouraud dextrose agar (SDA) and Sabouraud dextrose broth (SSB) culture media. In addition, nystatin was used as a standard antifungal agent for the positive control. The broth microdilution technique was performed to determine the Minimum Inhibitory Concentration (MIC) of the methanolic extract of Psidium guineense, all analyses and tests were performed in duplicate. In view of this, the MIC value higher than 1024 μg/mL was obtained, indicating that the methanolic extract of Psidium guineense did not present antifungal activity through the methodology used against the strains tested.