Bioavailability and antioxidant potential of rooibos flavonoids in humans following the consumption of different rooibos formulations.

In a complete crossover design, a human study with twelve healthy male volunteers has been conducted using a placebo and different rooibos drinks (rooibos tea and an isolated active fraction) from unfermented rooibos (Aspalathus linearis). Blood and urine samples were collected before and up to 24h after consumption of the drinks. By HPLC-MS/MS, seven metabolites of aspalathin and nothofagin were identified in urine samples, as well as intact aspalathin and nothofagin.