Antifungal and Antioxidant Activities of Vernonia Chalybaea Mart. ex DC. Essential Oil and their Major Constituent β-caryophyllene

This article describes the chemical composition of Vernonia chalybaea essential oil, and investigates its antimicrobial, antioxidant and hemolytic activities. The evaluation of the antifungal activity was performed by the broth microdilution method using strains of yeasts and dermatophytic fungi. The checkerboard technique to find antimicrobial modulatory effects was performed using ketoconazole as standard drug. The antioxidant activity was evaluated by DPPH scavenging assay and beta-carotene/linoleicacid system. The toxicity was characterized by the brine shrimp lethality test and hemolysis bioassays. The essential oil was obtained by hydrodistillation and analyzed by GC-MS method, showing to be rich in the sesquiterpenes beta-caryophyllene (39.06%) and bicyclogermacrene (19.69%), and also demonstrated a relevant antifungal activity against strains of Trichophyton rubrum. In the modulatory activity assay, the essential oil of V. chalybaea and beta-caryophyllene demonstrated a synergistic interaction with ketoconazole, with increasing of its antifungal action. The antioxidant activity was evidenced mainly by beta-carotene/linoleic acid system, with IC50 value of 35.87 +/- 0.32 mu g/mL. The results suggest that V. chalybaea essential oil and beta-caryophyllene are valuable natural medicinal agents with antioxidant and antimicrobial activities.