Caracterização química e avaliação in vitro das atividades antifúngica e anti-inflamatória do extrato em hexano de Mitracarpus frigidus (RUBIACEAE)

Abstract

Species of the genus Candida have great clinical importance, since they are among the main cause of systemic fungal infections, especially in immunocompromised patients. Candida albicans stands out both for being the most commonly isolated species in infections of the genus, and for its ability to develop resistance mechanisms. The present study aimed to chemically characterize and evaluate the in vitro antifungal and anti-inflammatory activities of the hexane extract of Mitracarpus frigidus (MFH), in order to discover a new treatment for fungal infections caused by C. albicans. MFH (22g) was obtained by liquid-liquid partition of 100g of the methanolic crude extract of the aerial parts of the species. From the chemical analysis by GC-MS it was possible to identify 11 substances in MFH, of these, pentalongin, squalene, neophytadiene, stigmasterol, γ-sitosterol and 2-azaantraquinone showed biological activity described in the literature and related to this work. The antifungal activity of MFH was evaluated against nine strains of the genus Candida, and the minimum inhibitory concentration (MIC) values ranged from 250 to 1000 μg/mL both with fungistatic effect. From these nine strains, three C. albicans strains were selected, which obtained the lowest MIC values (250 μg/mL). The other assays were performed only with the selected C. albicans strains: two standardized (ATCC® 24433 TM, sensitive to antifungals and ATCC® 10231 TM, resistant to antifungals) and one clinical strain of vulvovaginal origin (vv1). Changes were observed in the lag and log phases of the fungal growth curves of the analyzed strains treated with MFH and nystatin. Cell envelope assays showed that MFH acts on fungal cell membrane, interfering with cell integrity and inhibiting fungal growth. Regarding cytotoxic and anti-inflammatory activities in J774A.1 macrophages, MFH did not alter the cell viability of this strain, except at the highest concentration (300 μg/mL), and significantly reduced NO and TNF-α contents when compared to the control (macrophages stimulated and treated with vehicle). According to the results found, it can be inferred that the chemical composition of MFH, has a direct relationship with its anti-inflammatory and antifungal activities. Furthermore, it is noteworthy that this is the first report of both the chemical composition of MFH by GC-MS and its anti-inflammatory and antifungal activities against standard and clinical strains of C. albicans, opening perspectives for a new treatment against fungal infections arising from this species.