Evaporation of volatiles from essential oils of Japanese conifers enhances antifungal activity

Abstract

The antifungal properties of evaporation residue of essential oils (EOs) derived from the needles of the three Japanese planted conifer species Cryptomeria japonica, Pinus thunbergii and Thujopsis dolabrata var. hondae were evaluated. Open system mild heat treatments (MHTs) enhanced the volatilities of the EOs, leading to changes in their chemical composition. The activities of all EOs increased according to the monoterpene hydrocarbons evaporated, and then gradually decreased with the component degradation. These results indicated that the terpenoid components in lower volatile phase together with a variety of components could be responsible for the antifungal activities of these EOs. Further investigation also showed that the C. japonica EO showed the highest antifungal potential of the three EOs because it contained the major sesquiterpene alcohol elemol. This study represents the first reported time course investigation of changes in the chemical composition and antifungal properties of conifer needle EOs based on their volatility.