Bioflavonoids are water-soluble plant pigments with powerful antioxidant properties. Proanthocyanidins, polyphenols and catechins are some of the terms used in describing compounds of the bioflavonoid family. Grape seed extract contains oligomeric proanthocyanidins, providing protective support for capillaries and blood vessels. Resveratrol, the polyphenol most commonly associated with the health benefits of red wine, provides additional antioxidant support for blood vessel integrity. Catechins found in green tea are a class of polyphenols that promote cardiovascular, immune and cellular function. The antioxidant activity of green tea catechins, specifically epigallocatechin gallate, also protects cells from lipid peroxidation and has been shown to enhance antioxidant enzymes in skin exposed to sunlight. In addition, green tea has the potential to preserve and promote vitamin E levels in the body. Silymarin is a well-known bioflavonoid complex derived from milk thistle that stabilizes hepatic cell membranes and scavenges free radicals and toxins in the liver. One of silymarin's mechanisms may involve promoting superoxide dismutase antioxidant enzyme activity.