Bioavailability of lemon verbena (Aloysia triphylla) polyphenols in rats: Impact of colonic inflammation

Abstract

Lemon verbena (Aloysia triphylla) infusion, a widely consumed herbal tea, contains significant amounts of polyphenols such as flavone diglucuronides and phenylpropanoid glycosides (mainly verbascoside). We have recently shown that lemon verbena infusion offers beneficial effects against dextran sodium sulphate (DSS)-induced colonic inflammation in rats. The present study aimed to evaluate the bioavailability and intestinal absorption of polyphenols derived from lemon verbena infusion in both healthy and colitic rats. For this purpose, lemon verbena infusion was given to rats ad libitum for 14Â d, and then 4Â % DSS was added to the infusion for 7Â d. Before and after DSS administration, 24Â h urinary excretion of polyphenols was determined. Flavones were excreted in the urine as conjugated aglycones, and their excretion was not significantly altered by colonic inflammation. Only trace amounts of verbascoside were excreted in the urine, but various metabolites (hydroxycinnamic acids) were detected. The urinary excretion of hydroxycinnamic acids, particularly that of caffeic acid, increased after DSS administration (P