Cyanidin-3-glucoside (C3G) is a major anthocyanin pigment belonging to the flavonoid class, responsible for the red-purple coloration in berries, grapes, and other fruits. It consists of the anthocyanidin cyanidin glycosylated at the 3-position with a glucose moiety. C3G exhibits potent antioxidant, anti-inflammatory, and potential cardioprotective properties due to its ability to scavenge free radicals and modulate signaling pathways. It is pH-sensitive, appearing red in acidic conditions and shifting to blue/purple in neutral or alkaline environments. Widely studied for bioavailability and metabolic effects in humans.