Protocatechuic acid is the major human metabolite of cyanidin-glucosides.
The metabolic fate of dietary anthocyanins (ACN) has not been fully clarified in humans. In all previous studies, the proportion of total ACN absorbed and excreted in urine was <1% intake. This study aimed to elucidate the human metabolism of cyanidin-glucosides (CyG) contained in blood orange juice (BOJ). One liter of BOJ, containing 71 mg CyG, was consumed by 6 healthy, fasting volunteers. Blood, urine, and fecal samples were collected at baseline and at different times up to 24 h after juice consumption. The content of native CyG, glucuronidated/methylated derivatives, and various phenolic acids was determined by HPLC/MS/MS. The serum maximal concentration of cyanidin-3-glucoside (Cy-3-glc) was 1.9 +/- 0.6 nmol/L and that of protocatechuic acid (PCA) was 492 +/- 62 nmol/L at 0.5 h and 2 h after juice consumption, respectively. The calculated total amounts in plasma corresponded for Cy-3-glc to 0.02% and for PCA to 44% of CyG ingested. CyG and glucuronidated/methylated metabolites, but not PCA, were detected in urine. ACN recovered in 24-h urine collections represented approximately 1.2% of the ingested dose. Both CyG (1.90 +/- 0.04 nmol/g) and PCA (277 +/- 0.2 nmol/g) were recovered in 24-h fecal samples. Data explained the metabolic fate of 74% of BOJ ACN. PCA was for the first time, to our knowledge, identified in humans as a CyG metabolite, accounting for almost 73% of ingested CyG. A high concentration of PCA may explain the short-term increased plasma antioxidant activity observed after intake of cyanidin-rich food and it can also contribute to the numerous health benefits attributed to dietary ACN consumption.
Vitaglione
Paola
P
Department of Food Science, University of Napoli Federico II, 80055 Portici, Naples, Italy. paola.vitaglione@unina.it
Donnarumma
Giovanna
G
Napolitano
Aurora
A
Galvano
Fabio
F
Gallo
Assunta
A
Scalfi
Luca
L
Fogliano
Vincenzo
V
D000328:Adult; D000872:Anthocyanins / Q000378:metabolism* / Q000494:pharmacology; D002851:Chromatography, High Pressure Liquid; D005243:Feces; D005260:Female; D005960:Glucosides / Q000378:metabolism*; D006801:Humans; D062385:Hydroxybenzoates / Q000378:metabolism* / Q000652:urine; D008297:Male; D013058:Mass Spectrometry
D000872:Anthocyanins; D005960:Glucosides; D062385:Hydroxybenzoates; C009091:protocatechuic acid; C017154:cyanidin; C017616:phenolic acid