Effect of heat curing on antifungal activities of anise oil and garlic oil against Aspergillus niger on rubberwood

The effect of heat curing (30–100 °C) on the antifungal activity of rubberwood impregnated with anise oil and garlic oil (10–100 μl ml−1) against Aspergillus niger was examined. Essential oil constituents left within the rubberwood after the heat curing and after incubation were analyzed by GC–MS. Response surface methodology (RSM) with a central composite face-centered (CCF) design was employed to evaluate the time needed for initiation of mold growth. The mathematical models containing only significant parameters (p ≤ 0.05) as functions of treatment temperature and essential oil concentration were obtained. Heat curing adversely and positively influenced the antifungal activities of anise oil and garlic oil, respectively. Such thermal effect was more pronounced at a higher concentration of essential oil. Decomposition of trans-anethole and estragole in anise oil and formation of diallyl disulfide in garlic oil by heat was proposed as the agent responsible for temperature dependencies of the essential oil antifungal activities observed.

► We study heat curing effect on antifungal activity of essential oil on rubberwood.
► Heat curing reduces activity of anise oil against Aspergillus niger.
► Heat curing enhances activity of garlic oil against Aspergillus niger.
► Heat curing causes decomposition of trans-anethole and estragole in anise oil.
► Heat curing causes formation of diallyl disulfide in garlic oil.