Coumaroyl iridoids and a depside from cranberry (Vaccinium macrocarpon).

Cranberry (Vaccinium macrocarpon) juice has been used for urinary tract infections for approximately 50 years. Recent research suggests that this botanical blocks adherence of pathogenic E. coli to urinary tract cells, thus preventing infection. While current evidence indicates that proanthocyanidins are responsible for this activity, these compounds may not reach the urinary tract; thus further investigation is warranted. Fractionation of cranberry juice concentrate was guided by a recently published antiadherence assay, and the resulting fractions were phytochemically characterized. Two new coumaroyl iridoid glycosides, 10-p-trans- (1) and 10-p-cis-coumaroyl-1S-dihydromonotropein (2), and a depside, 2-O-(3,4-dihydroxybenzoyl)-2,4,6-trihydroxyphenylmethylacetate (3), were isolated, and although these compounds did not have antiadherent activity in isolation, they might constitute a new group of marker compounds for this active fraction of cranberry.