berries, ginkgo biloba , onions [28] [29] (particularly red onion [30] ), parsley , [31] pulses , [32] tea (especially white and green tea ), red wine , seabuckthorn , and dark chocolate (with a cocoa content of seventy percent or greater).flavonoids, derived from 2-phenyl chromen-4-one (2-phenyl-1,4- benzopyrone ) structure (examples: quercetin