Circadian Rhythm, and Antimicrobial and Anticholinesterase Activities of Essential Oils from Vitex gardneriana

Abstract

Vitex gardneriana, popularly known as “jaramataia”, is a shrub commonly found in the caatinga biome located in northeast Brazil. In folk medicine, its leaves have been used as analgesic and anti-inflammatory agents. Here we describe, for the first time, the chemical composition of the leaf essential oils extracted at 8.00, 12.00 and 17.00 h from V. gardneriana and report on their circadian rhythm, and antimicrobial and anticholinesterase activities. The essential oils’ antifungal activity was evaluated by a broth microdilution method using strains of dermatophytes, fungi and yeasts. The modulatory activity assays were performed by the checkerboard technique using ketoconazole as a standard drug, and acetylcholinesterase inhibitory activity was performed using Ellman's colorimetric method and compared with a reference acetycholinesterase inhibitor (physostigmine). The essential oils extracted from the leaves were analyzed by GC/MS and GC/FID. Twenty-five constituents (94.7%) were identified in the 8 o'clock oil, these being 2 monoterpenes (0.4%) and 23 sesquiterpenes (94.3%). For the essential oil extracted at 12 o'clock, 26 constituents (91.8%) were identified, of which 2 were monoterpenes (0.3%) and 24 sesquiterpenes (91.5%). For the essential oil extracted at 17.00 h, 32 constituents (91.4%) were identified, of which 5 were monoterpenes (3.4%) and 27 sesquiterpenes (88%). The main constituents of the 8.00, 12.00 and 17.00 h essential oils were the sesquiterpenes cis-calamenene (27.9, 24.5 and 25.8%), 6,9-guaiadiene (21.8, 11.2 and 18.4%) and caryophyllene oxide (16.7, 26.3 and 13.8%), respectively. The essential oils showed activity against strains of Trichophyton rubrum.