Composição química e atividade biológica do extrato hidroalcoolico de própolis preta.

Abstract

We studied the chemical composition of the black propolis extract, and its in vitro antifungal and antibacterial effects against yeasts of the genus Candida spp. (six species) and the bacterium Staphylococcus aureus. The propolis from Mimosa hostilis (Jurema-preta) flowers was provided by the Edimel apiary. Black propolis was extracted, and its chemical composition was measured by High-Performance Liquid Chromatography. Hydroalcoholic extracts of black propolis were done through two methods, hot maceration and Soxhlet, to obtain the best synthesis and yield. The yeasts were rehydrated and sown, whereas the bacterium was replicated. Viable samples were tested for sensitivity profile and classified as: sensitive, dose-dependent, and resistant. For the disc diffusion test, we followed reference methods described in the M44-A2 and M2-A8 documents of the Clinical and Laboratory Standards Institute, respectively for Candida spp. and S. aureus. The chemical profile of black propolis comprises 14 chemical substances. The compounds with highest concentrations were: protocatechuic acid (14.19 mg/mL), rutin (12.71 mg/mL), and trans-cinnamic acid (6.25 mg/mL), which were responsible for the antioxidant and antibacterial activity. The hydroalcoholic extraction processes of propolis by hot maceration and Soxhlet resulted in yields of 43.6% and 57.6%, respectively. Thus, the Soxhlet extraction showed better viability due to its faster extraction and increase in temperature. After rehydration and sowing, all samples of yeast cultures showed satisfactory growth for the sensitivity tests. All Candida species were resistant to the extract of black propolis (at the concentrations of 26.4 mg/mL – 33%; 52.8 mg/mL – 66%; and 79.2 mg/mL – 99%), and to 70% ethanol, whereas they were sensitive to fluconazole at 25 mg/mL, the antifungal marker. The S. aureus was sensitive to the extracts at all concentrations and to chloramphenicol at 30 mg/mL, the antibacterial marker. The halos around the discs show the sensitivity of S. aureus to both hydroalcoholic extracts of black propolis, whose diameters ranged from 19 to 25.3 mm, while the marker halos ranged from 30 to 30.1 mm. So, the black propolis showed antibacterial activity against S. aureus but no antifungal activity against Candida spp. The antibacterial activity occurred due to the presence of phenolic and flavonoid compounds. The predominance of these bioactive compounds affects the biological activity of microorganisms.