Pterostilbene, a Natural Methoxylated Analog of Resveratrol, Exhibits Antifungal Activity Induced by Reactive Oxygen Species Production and Plasma Membrane Injury

Pterostilbene has been shown to exhibit antifungal activities. However, the detailed action mechanism is unknown. Here, we analyzed the antifungal mechanism of pterostilbene against Saccharomyces cerevisiae. The minimum growth inhibitory and fungicidal concentrations of pterostilbene were 120 and 240 µM in a YPD medium, respectively. Although pterostilbene produced reactive oxygen species (ROS), resveratrol did not. This effect was maximized at 120 µM. Furthermore, α-tocopherol acetate inhibited ROS production and reversed pterostilbene-induced growth inhibition. At 240 µM, pterostilbene showed fungicidal effects accompanied by the leakage of intracellular potassium ions, suggesting the involvement of membrane injury in addition to oxidative stress in fungicidal action. Nevertheless, the antioxidants gradually reversed the decrease in cell viability caused by pterostilbene, suggesting that ROS production mainly contributed to the lethal effect. As Pterocarpus marsupium extract, mainly containing pterostilbene, is used as a traditional medicine, pterostilbene has great potential for development as a preservative with fewer adverse effects.