Chemical composition and antifungal activity of essential oil and fractions extracted from the leaves of Laurus nobilis L. cultivated in Southern Brazil

摘要

Laurus nobilis L., popularly known as laurel, is a tree belonging to the Lauraceae family, native to Asia. It has long been used in traditional medicine to treat rheumatic disorders, and as a gastric stimulant. The aim of this study was to characterize the chemical composition of essential oils (EO) and fractions from laurel by column chromatography, and to evaluate their antifungal activity. The EO of L. nobilis leaves was obtained by hydrodistillation, and separated by column chromatography. Thirty-two EO constituents were identified, with 1,8-cineole and linalool comprising 40.14 and 15.69% of the total yield, respectively. The major constituents of the fractions (FR) were: α-terpinyl acetate (FR1: 52.65%), 1,8-cineole (FR2: 76.88%), 1,8-cineole (FR3: 84.24%), linalool (FR4: 67.26%), and linalool (FR5: 90.64%). Antifungal activity of EO and fractions were tested by a broth microdilution method, whereby minimum inhibitory concentration (MIC) was determined against several fungal organisms (Candida albicans, Candida krusei, Candida parapsilosis, Candida tropicalis, Cryptococcus gattii, and Cryptococcus neoformans). EO showed moderate inhibition of C. neoformans (MIC 0.62 mg/mL), and strongly inhibited of C. gattii (MIC 0.31 mg/mL). FR3 moderately inhibited C. neoformans (0.62 mg/mL), and strongly inhibited C. gattii (MIC 0.31 mg/mL). FR5 moderately inhibited strains of C. gattii and C. neoformans (MIC 0.62 mg/mL). Laurel′s EO and the fractions analyzed in this study were confirmed to have antifungal properties. However, further studies on toxicity of these substances and in vivo experiments are necessary to confirm the results presented herein.