Quercetin‚ is a bioflavonoid‚ usually found in onions, apples and capers. Bioflavonoids are plant pigments. Quercetin appears to have antiviral, antioxidant, anti-inflammatory and antihistaminic effects. Zinc is an essential micromineral, found in all organs, tissues and body fluids. It is primarily an intracellular mineral and is required for the activity of several hundred enzyme systems of the human body.