In vitro catabolism of 3′,4′-dihydroxycinnamic acid by human colonic microbiota

3 ',4 '-Dihydroxycinnamic acid (aka caffeic acid) is a common dietary component found in a variety of plant-derived food products either in a free form or esterified as in chlorogenic acids such as 5-O-caffeoylquinic acid. The dihydroxycinnamate is produced principally by hydrolysis in the colon of 5-O-caffeoylquinic acid and other caffeoylquinic acid esters, and is catabolised by the resident microbiota prior to absorption. In the present study 3 ',4 '-dihydroxycinnamic acid was incubated in vitro, with or without glucose, under anaerobic conditions with faecal slurries obtained from five volunteers. The main resultant catabolites to accumulate were 3-(3 ',4 '-dihydroxyphenyl)propanoic acid (aka dihydrocaffeic acid), 3-(3 '-hydroxyphenyl)propanoic acid and phenylacetic acid. Both the rate of degradation of the hydroxycinnamate substrate and the catabolite profile varied between the faecal samples from the individual volunteers. Overall there was no clear cut effect when glucose was added to incubation medium.

Automated summary

The study found that 3',4'-dihydroxycinnamic acid can produce various metabolites under the action of intestinal microbiota, with differences in degradation rate and metabolite profile among fecal samples from different volunteers. There was no clear effect observed when glucose was added to the in vitro culture of 3',4'-dihydroxycinnamic acid.