Evaluation of Absorption and Plasma Pharmacokinetics of Tyrosol Acyl Esters in Rats

Lipophenols are regarded as an emerging source of functional food ingredients. However, little is known about their in vivo digestion, absorption, and metabolism. Thus, the pharmacokinetic characteristics in rat and the gut microbial degradation of tyrosol acyl esters (TYr-Es) with fatty acids of C12:0, C18:0, and C18:2 were investigated for the first time. Major metabolites including tyrosol sulfate and tyrosol glucuronide, rather than the parent compounds, were detected in rat plasma after oral administration of TYr-Es. The increased plasma half-life (T-1/2) and mean residence time demonstrated that TYr-Es display a longer duration of action in vivo than TYr, potentially leading to higher oral bioavailability. TYr-Es could be hydrolyzed by the gut microbiota to free TYr, which may result in the appearance of the second absorption peak in pharmacokinetic profiles. Therefore, TYr-Es exhibit improved bioavailability compared to that of TYr because of their prolonged duration of action.