The origin of urinary aromatic compounds excreted by ruminants 2. The metabolism of phenolic cinnamic acids to benzoic acid

Abstract

1. The extent to which phenolic derivatives of benzoic acid (seven); of phenylacetic acid (one); of 3-phenylpropionic acid (one) and of cinnamic acid (six) served as precursors of the urinary benzoic acid excreted by sheep was determined after administration as continuous drips via rumen or abomasal cannulas.2. Phenolic derivatives of benzoic or of phenylacetic acid were not dehydroxylated to yield aromatic acids following administration via either route.3. Rumen infusion of phenolic derivatives of both 3-phenylpropionic and cinnamic acids gave enhanced rumen concentrations of 3-phenylpropionic acid'with negligible amounts of benzoic acid. Between 63 and 106% of the 2-, 3-or 4-hydroxy acids, of the 3,4-dihydroxy acids or of the 3-rnethoxy, 4-hydroxy acids infused were excreted in the urine as benzoic acid and a variable proportion, characteristic of the individual animal, of up to 20% of the dose as cinnamic acid.4. Abomasal infusion of monohydroxy 3-phenylpropionic and cinnamic acids did not yield urinary benzoic acid increments. However, between 1 1 and 34% of abomasally-infused disubstituted phenolic cinnamic acids infused were excreted in the urine as benzoic acid due, it is postulated, to entero-hepatic circulation and microbial metabolism of the infused acids in the large intestine.5. It is concluded that rumen microbial metabolism of dietary phenolic cinnamic acids to 3-phenylpropionic acid followed by its absorption and oxidation in the body tissues is responsible for the greater part of the benzoic and cinnamic acids found in ruminant urine.

Anti-Inflammatory Implications of the Microbial Transformation of Dietary Phenolic Compounds

“…1 and 3). As well as human microbiota having the ability to perform these reactions, incubations with rumen microbes gave almost identical results, which were similar to transformations observed in earlier studies (18). For the 5-5 linked dehydrodimer of ferulic acid (Fig.…”

Transformations of (14C‐lignin) cell walls of wheat by rumen microorganisms

“…This fraction probably corresponds to small acid soluble molecules, such as phenolic acids, VFA, oligolignols and phe-bound peptides. It has been observed that released hydroxycinnamic acids (Martin 1982) and phenylalanine (Scott et a1 1964) are transformed in the rumen into soluble phenyl-substituted fatty acids. To estimate the proportion of RAtrans actually resulting from the degradation of lignin into small acid-soluble molecules, we can deduct the radioactivity of the released labelled phenolic acids (6.7% pheCWRRA) and all the labelled proteins (5% pheCWRRA, according to Mosoni et a1 1993) from the radioactivity of the supernatants.…”

Hydroxycinnamic acids in the digestive tract of livestock and humans

“…16,17 Infusing phenolic acid into the sheep rumen established hydroxycinnamates released from cell walls or from soluble conjugates as the major source of these acids. 18 The alternative origin via the deamination of aromatic amino acids was shown subsequently to account for only a minor proportion of such compounds. 19 The transformation of nonmethoxylated and monomethoxylated hydroxycinnamic acids to 3-phenylpropionic acid is under the control of microbial enzymes and involves the reduction of the side-chain, demethylation of C 3 ferulic and sinapic acids and dehydroxylation (Fig 1).…”