Anthocyanins Exist in the Circulation Primarily as Metabolites in Adult Men1

Anthocyanins are reported to have many “health promoting” properties; however, despite numerous reports of their bioactivities, their absorption and metabolism in humans are poorly understood. The objective of this research was to detail the pharmacokinetic parameters of anthocyanins after the administration of a 721-mg oral dose of cyanidin 3-glycosides from chokeberry extract to human subjects. Solid-phase extraction, preparative-HPLC, preparative-TLC, HPLC-diode array detection, HPLC-MS, and NMR were utilized to isolate, identity, and quantify anthocyanins in 0- to 7-h (0, 1, 2, 3, 4, 5, 6, 7 h) serum and 0- to 24-h urine samples (total individual urine voids over 24 h). The cumulative concentration of total anthocyanins (parent and metabolites) detected in the serum (0–7 h) was 376.65 ± 16.20 (nmol · h)/L (area under the concentration time curve), reaching a maximum concentration (Cmax = 96.08 ± 6.04 nmol/L) within 2.8 h. The parent anthocyanins represented only 32.0% [120.63 ± 2.85 (nmol · h)/L] of the total anthocyanins detected with 68.0% [256.02 ± 5.23 (nmol · h) identified as conjugated metabolites. Additionally, the total urinary excretion of anthocyanins over 24 h was 1071.54 ± 375.46 μg, reaching a maximal rate of excretion (Rmax = 202.74 ± 85.06 μg/h) at 3.72 ± 0.83 h. Parallel to the serum data, only 32.5% (347.85 ± 60.61 μg) of the anthocyanins excreted in the urine (total 24 h) were the parent compounds with 67.5% (723.69 ± 92.59 μg) occurring as conjugated metabolites. The metabolites were identified as glucuronidated and methylated derivatives of the parent cyanidin 3-glycosides. The above results indicate that cyanidin 3-glycosides are rapidly absorbed and metabolized extensively following a moderate-to-high oral dose in humans.