Antifungal activity and mechanism of action of carvacrol and thymol against vineyard and wine spoilage yeasts

•Carvacrol and thymol showed potent antifungal activity against wine spoilage yeasts.•Antifungal action was due to membrane damage and leakage of cytoplasmic content.•Carvacrol/thymol holds promise as preservative for control of wine spoilage yeasts.

Antimicrobial activity of carvacrol and thymol against natural yeast flora of the grapes and yeasts known to cause wine spoilage was examined. Carvacrol and thymol exhibited comparable or better antifungal activity than potassium metabisulphite, commercially used wine preservative, against the natural yeast flora and spoilage yeasts. The antifungal activity for both the compounds was better at pH 3.5 than pH 6.5. Addition of carvacrol and thymol (64 μg/mL) in red wine resulted in inhibition of growth of the spoilage yeasts. Carvacrol and thymol exerted their antimicrobial action through membrane damage, leakage of cytoplasmic content and ergosterol depletion. In conclusion, carvacrol and thymol holds promise as a potential natural preservative for the control of wine spoilage.