EPR studies of O₂^•-, OH, and ¹O ₂ Scavenging and prevention of glutathione depletion in fibroblast cells by cyanidin-3-rhamnoglucoside isolated from fig (Ficus carica L.) Fruits

Cyanidin-3-rhamnoglucoside (C3R) is the major anthocyanin in fresh fig fruits. In this study, the free radical scavenging potential of C3R was evaluated in vitro using several free radical generators. This naturally occurring anthocyanin was superior to other tested natural antioxidants in scavenging ABTS^•+. Electron paramagnetic resonance served to determine the scavenging properties of C3R toward superoxide radical anion (O₂^•-), hydroxyl radical (^•OH), and singlet radical (¹O₂). The protection of NIH-3T3 fibroblast cells was then tested as the inhibition of reactive oxygen species (ROS) formation in a dose-dependent manner. It was further demonstrated that treatment with C3R elevates the reduced glutathione (GSH) concentration and the redox ratio (GSH/GSSG) in fibroblast cells in a dose-dependent manner. Moreover, C3R reduced the induction of ROS by butathionine sulfoximine (BSO) and elevated the redox ratio. Thus, it is suggested that C3R in fresh fig fruits is a potent scavenger and may influence endogenous antioxidant systems of consumers.