Avaliação fitoquímica, potencial antifúngico, antioxidante e citotóxico de Pimenta pseudocaryophyllus (Gomes) Landrum (Myrtaceae)

Abstract

The purpose of this work is to carry out the phytochemical study, evaluate the potential antifungal against the major strains causing sporotrichosis in Brazil, the antioxidant activity and the preliminary cytotoxicity of essential oils obtained commercially (CMO) and obtained by extraction in Pharmacognosy Laboratory of Pharmacy Faculty of the Federal University of Juiz de Fora (OEX) and hydroethanolic extract 95% (v/v), obtained from the leaves of Pimenta pseudocaryophyllus (Gomes) Landrum (Myrtaceae). The phytochemical screening performed with the hydroethanolic extract resulted in the identification of flavonoids, tannins and proanthocyanidins. The quantification of these secondary metabolites in plant drug, by UV-VIS revealed the presence of phenolic constituents (18.77%), tannins (10.69%) and flavonoids (0.52%). The chromatographic profile obtained by GC-MS indicated the OEX high levels of monoterpenes (48.83%) and phenylpropanoids (39.08%) having as a major constituent eugenol (34.38%). The OCM had high levels of sesquiterpenes (25.64%) and phenylpropanoids (70.05%), with as major constituent eugenol (66.93%). Extract and fractions showed notable antioxidant activity by reduction of DPPH method, it is suggested that it be attributed to the high concentration of phenolic compounds, flavonoids and tannins found. Promising results of antioxidant activity were found for the OEX and OCM, which have as major constituent eugenol. For evaluating the antifungal activity the following fungal strains were used: Sporothrix schenckii ATCC 1099-18, Sporothrix schenckii IPEC 15383, Sporothrix brasiliensis ATCC 5110 and Sporothrix brasiliensis IPEC 17943 and two clinical strains, known generically as A and B. The OEX showed activity antifungal against all strains at concentrations ranging from 260.46 to 520.90 μg/mL. It was observed fungicidal activity against all strains at concentrations above 520.90 μg/mL. The OCM was able to inhibit all strains at concentrations ranging from 65.52 to 260.10 μg/mL. It was observed fungicidal activity against all strains at concentrations above 262.10 μg/mL. The eugenol showed antifungal activity against all strains at concentrations ranging from 34.36 to 137.48 μg/mL. It was observed fungicidal activity against all strains at concentrations above 137.48 μg/mL. By adjusting the results of antifungal activity to 100% of major constituent eugenol, it was found that there is synergy between the constituents of the OEX, with the highest antifungal activity (MIC = 89.54 μg/mL) than eugenol (MIC = 136.11 μg/mL) for four of the six strains studied. It was noted that only two of the studied strains were susceptible to amphotericin B and three strains were considered resistant cetononazol with MIC values of 4.0 μg/mL. Compared to itraconazole, all the strains studied were considered resistant with MIC values> 128 μg/mL. The micrographs revealed that the fungal strains in both fungi exposed to the experimental treatments, as those exposed to the reference drug, one can observe fungal deformities in structure when compared to the untreated group. In relation to the cytotoxicity assays performed with murine fibroblasts (L929) by the MTT reduction method, the extract showed no cytotoxicity at concentrations tested (10 to 100 μg/mL), eugenol showed no cytotoxicity at concentrations less than or equal to 125 μg/mL, OCM was not toxic at concentrations less than or equal to 250 μg/mL. In relation to the OEX concentrations below or equal to 62.5 μg/mL showed no toxicity.