A bioflavonoid is any one of a group of biologically active substances found in plants. They serve in the maintenance of the walls of small blood vessels in mammals.
Notable sources of bioflavonoids of interest to humans include red wine, green tea, onions, grapefruit seeds, apples, and other fruits and berries. Recent US research indicates that chocolate high in cocoa content (70% or more) may be the richest food source of flavonoids such as epicatechin.
