Quercetin, a flavonoid abundant in black tea, has shown promise in protecting blood vessels against oxidative damage and lowering cardiovascular disease (CVD) risk, said researchers who based their studies on mice. Flavonoids are common plant pigment compounds that act as antioxidants, enhance the effects of vitamin C, and protect connective tissue around capillaries (blood vessels). Natalie Ward, research fellow from the University of Western Australia (UWA) School of Medicine, and pharmacology professorial fellow Kevin Croft said although their preliminary study is based on cells and isolated mouse vessels, "our findings have suggested that quercetin is able to protect vessels against oxidant-induced damage." The supervisors say there is evidence to suggest that other dietary flavonoids may reduce blood pressure as well as bring down the development of atherosclerosis (plaque build-up in arteries), the journal Biochemical Pharmacology reports. "Future studies looking at the effect of flavonoids on CVD should consider using combinations of flavonoids, as well as dietary sources of flavonoids, rather than supplementation with pure flavonoids," said Ward and Croft, according to an UWA statement.