Anthocyanins Are Detected in Human Plasma after Oral Administration of an Elderberry Extract

Abstract

Anthocyanins are a group of natural antioxidants (1)(2)(3)(4) widely distributed in fruits and vegetables. Anthocyanins have two absorbance peaks, at 270–280 nm and 510–540 nm, respectively. The intake of anthocyanins in humans has been estimated to be 180–215 mg/day in the US (5), which is much higher than the intake (23 mg/day) of other flavonoids, including quercetin, kaempferol, myricetin, apigenin, and luteolin (6). Various biological and pharmacological activities of anthocyanins have been reported using crude fruit extracts, which are rich in anthocyanins (7). However, the absorption of dietary anthocyanins has never been shown clearly in humans, although one substance with an absorbance spectrum similar to those of the anthocyanins was reported in the plasma of nonsupplemented human subjects (8), and anthocyanin-like compounds have been found in human urine (9). We report here direct evidence of the absorption of anthocyanins in humans, which was obtained by combining an octadecylsilane (ODS) solid-phase extraction procedure for plasma sample preparation and an HPLC system with diode array for anthocyanin separation and detection. One male subject (one of the authors), 35 years of age, consumed 25 g of elderberry extract containing 1.5 g of total anthocyanins after fasting overnight. The elderberry extract is commercially available as a nutritional supplement for humans. Its main constituents are anthocyanins, mainly cyanidin 3-glucoside and cyanidin 3-sambubioside; other polyphenols were very limited (10). Blood samples were obtained before and 30 and 60 min after anthocyanin consumption. The EDTA blood samples were centrifuged at 500 g for 10 min at 4 °C, and the plasma was quickly removed. A …