Antioxidant and Geno-protective Effects of Naturally Occurring Delphinidin Glycosides

Anthocyanins are flavonoid pigments responsible for red, blue, and purple coloration in plants and play a protective role against abiotic stress through reactive oxygen species scavenging. They are abundant in the human diet, with berries serving as a primary source. These flavonoids are known for their antioxidant and potential geno-protective properties. However, the effect of glycosylation on their biological activity remains incompletely understood. This study investigated the influence of glycosylation on the antioxidant and DNA-protective effects of delphinidin (aglycone), comparing the aglycone with pure glycosylated derivatives and a standardized Maqui berry extract 'PREVAID' rich in delphinidin glycosides. Using human colon adenocarcinoma (Caco-2) cells, oxidative stress was induced with hydrogen peroxide (H₂O₂) and assessed via 2',7'-dichlorodihydrofluorescein diacetate (DCFH₂-DA). Oxidative DNA damage protection was evaluated with the formamidopyrimidine DNA glycosylase (FPG)-modified comet assay, and geno-protection against cytochrome P450-mediated activation of riddelliine was assessed by the micronucleus assay in human hepatoma (HepG2) cells. Both delphinidin and its glycosylated derivatives significantly reduced intracellular ROS and protected against oxidative DNA damage. Protective effects persisted following medium replacement, indicating intracellular uptake and activity. In the micronucleus assay, delphinidin and its glycosides attenuated riddelliine-induced genotoxicity, suggesting interference with cytochrome P450-mediated metabolic activation. These findings demonstrate that glycosylation does not abolish the antioxidant and geno-protective properties of delphinidin. The results have important implications for understanding dietary anthocyanin bioactivity and guiding the development of anthocyanin-based nutraceuticals.