Phenolic acid metabolism

Phenolic acid metabolism. During the last 30 years, much has been learned about the production of phytotoxins during plant residue decomposition in the laboratory and in the field ( -, 18). However, little is known about the fate of these molecules in the soil. 

Tamagnone, L. et al.. Inhibition of phenolic acid metabolism results in precocious cell death and altered cell morphology in leaves of transgenic tobacco plants. Plant Cell, 10, 1801, 1998. 

Barthelmebs L., Divies, C. and Cavin, J.F. (2000) Knockout of the >-coumarate decarboxylase gene from Lactobacillus plantarum reveals the existence of two other inducible enzymatic activities involved in phenolic acid metabolism. Appl Environ Microbiol 66, 3368-3375. 

Finally, the fact that anthocyanins can reach the brain represents a beginning of an explanation of the purported neuroprotection effects of anthocyanins. Anthocyanins may be eliminated via urinary and biliary excretion routes. " The extent of elimination of anthocyanins via urine is usually very low (< 0.2% intake) in rats and in humans, indicating either a more pronounced elimination via the bile route or extensive metabolism. As mentioned earlier, in the colon, non-absorbed or biliary excreted anthocyanins can be metabolized by the intestinal microflora into simpler break-down compounds such as phenolic acids that may be (re)absorbed and conjugated with glycine, glucuronic acid, or sulfate and also exhibit some biological... 

Soil microorganisms produce many compounds that are potentially toxic to higher plants. Examples include members of the following antibiotics (1-6), fatty and phenolic acids (7-12), amino compounds (13-15), and trichothecenes (16, 17). "Soil sickness" and "replant problems" have been reported where certain crops or their residues interfere with establishment of a subsequent crop (18, 19). Toxins resulting from microbial activity sometimes are involved, but it is often unclear whether these are synthesized de novo in microbial metabolism or are breakdown products of the litter itself (20). 

Pseudomonas grown on phenol and various cresols combusts them at 25° in 300-600 sec if there are excess cells, 1-2 mg dry weight, and limited carbon, 5-30 nanomoles. Figure 3 shows that when Pseudomonas is adapted to o-cresol, it combusts o-cresol and phenol to completion in about 6 minutes. Grown on vanillic acid, Pseudomonas metabolizes limited amounts of vanillic acid, albeit somewhat more slowly than in the o-cresol or phenol utilizing system. Nevertheless, this occurs in far shorter times than can possibly be observed by a growth response. Ten to twenty nanomoles of vanillic acid metabolize ca. 30-50% as rapidly as o-cresol or phenol. 

Finally, several works have also implicated the nutrients P and Fe as possible inductors of changes in phenolic metabolism. However, studies of these relationships have been scarce. With regard to the former nutrient, P deficiency has been observed to raise the level of anthocyanins, but the reason for this rise remains unclear [4]. Meanwhile, low levels of Fe can increase the release of phenolic acids, presumably to help solubilize metals and thereby facilitate their uptake [135]. 

Caco-2 cells have also been used to study the metabolism of phenolic acids. Contrary to the transport studies, which usually use the cells grown on semipermeable filters (two compartments), the cultures used to study metabolism are prepared with cells grown and partially differentiated on dishes (one... 

Scheline RR. 1968. Metabolism of phenolic acids by the rat intestinal microflora. Acta Pharmacol Toxicol (Copenh) 26 189-205. 

In spite of the lack of specificity of the method, it is obvious that amines which give a color by Richter s method (48) are usually increased in chronic hypertension, especially in the more severe forms. Because the more highly active phenolic amines are not measured by this method, and others might be present in too small amounts to measure, these results may be taken as a manifestation of a general disturbance of amino acid metabolism in chronic hypertension which may include the formation of pressor amines it does not prove their presence. 

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