Phytochemical properties of black tea () and rooibos tea (); and their modulatory effects on key hyperglycaemic processes and oxidative stress.

The comparative phytochemicals, antioxidative and antidiabetic activities of (black tea) and (rooibos tea) were studied in vitro and ex vivo. Concentrated infusions of the teas showed significant free radical scavenging activities in vitro. They significantly increased the glutathione level, superoxide dismutase and catalase enzyme activities in oxidative hepatic injury, while concomitantly depleting malondialdehyde level. The teas significantly inhibited intestinal glucose absorption and α-amylase activities, and elevated muscle glucose uptake. LCMS phytochemical profiling revealed the presence of hydroxycaffeic acid, l-threonate, caffeine, vanillic acid, n-acetylvaline, and spinacetin 3-glucoside in . While quinolinic acid, coumestrol, phloroglucinol, 8-hydroxyquercetagetin, umbelliferone, and ajoene were identified in . These results portray the antioxidant and antidiabetic potencies of both teas, with showed better activity compared to . These teas may thus be used as functional foods in the management of diabetes and other oxidative stress related metabolic disorders.