Bioavailability of apigenin from apiin-rich parsley in humans

Aim: Absorption and excretion of apigenin after the ingestion of apiin-rich food, i.e. parsley, was tested. Methods: Eleven healthy subjects (5 women, 6 men) in the age range of 23-41 years and with an average body mass index of 23.9 ± 4.1 kg/m² took part in this study. After an apigenin- and luteolin-free diet, a single oral bolus of 2 g blanched parsley (corresponding to 65.8 ± 15.5 μmol apigenin) per kilogram body weight was consumed. Blood samples were taken at 0, 4, 6, 7, 8, 9, 10, 11 and 28 h after parsley consumption and 24-hour urine samples were collected. Apigenin was analyzed in plasma, urine and red blood cells by means of HPLC-ECD. Results: On average, a maximum apigenin plasma concentration of 127 ± 81 nmol/l was reached after 7.2 ± 1.3 h with a high range of variation between subjects. For all participants, plasma apigenin concentration rose after bolus ingestion and fell within 28 h under the detection limit (2.3 nmol/l). The average apigenin content in 24-hour urine was 144 ± 110 nmol/24 h corresponding to 0.22 ± 0.16% of the ingested dose. The flavone could be detected in red blood cells without showing dose-response characteristics. Conclusions: A small portion of apigenin provided by food reaches the human circulation and, therefore, may reveal biological effects.