Cancer Chemopreventive and Antioxidant Activities of Pterostilbene, a Naturally Occurring Analogue of Resveratrol

Pterostilbene, a natural methoxylated analogue of resveratrol, was evaluated for antioxidative potential. The peroxyl-radical scavenging activity of pterostilbene was the same as that of resveratrol, having total reactive antioxidant potentials of 237 ± 58 and 253 ± 53 μM, respectively. Both compounds were found to be more effective than Trolox as free radical scavengers. Using a plant system, pterostilbene also was shown to be as effective as resveratrol in inhibiting electrolyte leakage caused by herbicide-induced oxidative damage, and both compounds had the same activity as α-tocopherol. Pterostilbene showed moderate inhibition (IC50 = 19.8 μM) of cyclooxygenase (COX)-1, and was weakly active (IC50 = 83.9 μM) against COX-2, whereas resveratrol strongly inhibited both isoforms of the enzyme with IC50 values of approximately 1 μM. Using a mouse mammary organ culture model, carcinogen-induced preneoplastic lesions were, similarly to resveratrol, significantly inhibited by pterostilbene (ED50 = 4.8 μM), suggesting antioxidant activity plays an important role in this process. Keywords: Cyclooxygenase; mouse mammary gland organ culture; total reactive antioxidant potential; electrolyte leakage