Efficacy of Artemisia annua essential oil against Malassezia spp.

Artemisia annua L. (Asteraceae) is native to China, now naturalised in many other countries, well known as the source of the unique sesquiterpene endoperoxide lactone artemisinin, and used in the treatment of the chloroquine-resistant and cerebral malaria. The essential oil is rich in mono- and sesquiterpenes and represents a by-product with medicinal properties. Besides significant variations in its percentage and composition have been reported (major constituents can be camphor (up to 48%), germacrene D (up to 18.9%), artemisia ketone (up to 68%), and 1,8 cineole (up to 51.5%)), the oil has been subjected to numerous studies supporting exciting antibacterial and antifungal activities [1]. In continuing our studies on A.annua essential oil [2,3] we investigated the activity against some Malassezia species closely related to many skin disorders in man and animals. Considered the good frequency percentage of volatile compounds of this oil the tests were carried out either in liquid phase and in vapor phase. Essential oil of A. annua showed strong antimicrobial activity in both tests and towards every species of Malassezia analyzed. The MFC results demonstrated a strong fungicidal activity of A.annua EO on most of Malassezia strains tested, with values from 0.78 uL / mL to 1.56 uL / mL. Only three strains of M.sympodialis have required a higher concentration of 3.125 UL / mL. Overall the MICs obtained by the vapour diffusion assay were lower than those obtained by the liquid method. For example, by comparing for each species the average values of MIC obtained by the two methods at 72 h, they are higher (1.3 to 8 times) in liquid method, respect to those in the vapour phase.