Urinary excretion kinetics of (poly)phenolic metabolites derived from the consumption of microwaved Piquillo pepper (Capsicum annuum cv. Piquillo)†

Consumption of (poly)phenol-containing foods, such as pepper (Capsicum annuum), may have a positive impact on preventing non-communicable diseases. However, native (poly)phenols are extensively transformed, either mediated by the colonic microbiota or as a result of enzymatic phase II reactions. Considering the great interest in these metabolites as biologically active compounds, the present research aimed to evaluate the in vivo metabolism and bioavailability of the phenolic metabolites produced after the consumption of microwaved Piquillo pepper (C. annuum cv. Piquillo). The human intervention study involved 10 healthy volunteers who consumed a portion (90 g) of microwaved Piquillo pepper. Urine was collected before and 24 h after intake at different time intervals. (Poly)phenol metabolites were extracted using μ-SPE and analysed by UHPLC-ESI-QqQ-MS/MS. Twenty urinary metabolites (out of 37 metabolites identified) were exclusively associated with the consumption of microwaved Piquillo pepper, mainly represented by cinnamic and phenylpropanoic acid derivatives (86.2%). Glucuronidation was the main phase II transformation observed after absorption. From the total urine metabolites (17.78 ± 3.20 μmol), the majority were excreted between 4 and 24 hours (11.73 ± 2.80 μmol), suggesting that absorption of (poly)phenols from Piquillo pepper occurs after extensive metabolism in the large intestine. Urinary metabolites showed great interindividual variability in concentration (2.52–30.28 μmol) and metabolite patterns, associated likely with gut microbiota differences. Overall, these metabolites are the ones that could exert health promoting effects at the systemic level, rather than native (poly)phenols. This study paves the way to better understand the benefits of pepper consumption after processing.