Low-Molecular Weight Bacterial Metabolites in Host-Microbial Interaction

Abstract

The review gives an insight into inherent biological properties of bacterial metabolites-low-molecular weight Phenylcarboxylic Acids (PCAs), including Benzoic Acid (BA), p-Hydroxyphenyllactic Acid (HPLA), Phenyllactic Acid (PLA), p-Hydroxyphenylacetic Acid (HPAA), Phenylacetic Acid (PAA), and Phenylpropionic Acid (PPA). It has been demonstrated that bacteria from human microflora-predominantly anaerobes-can metabolize aromatic amino acids into PCAs, and PCAs are capable to suppress the growth and propagation of other bacteria, entering competitive interactions within microbial associations. The authors suggest that in the human colon, where concentrations of microbial metabolites reach biologically active level, PCAs may exert not only local, but also systemic effects, thus any deviation from existing composition of microbial associations may potentially result in the breakdown of habitual PCAs balance and emergence of PCAs with opposite biological properties. Available published data as well as findings from own research allowed us to substantiate a novel approach directed at the development of new therapeutic strategies based on regulation of local and systemic balance of microbial aromatic metabolites in the human body.

Gut microbiota-associated metabolites and risk of ischemic stroke in REGARDS

“…The aromatic amino acids tyrosine, tryptophan, and phenylalanine and their derivatives play a central role in metabolism among human gut microflora, which in turn metabolize these substrates into phenyl carboxylic acids. 36,37,46 Altered abundance of these metabolites has previously been implicated in acute stroke, including elevated kynurenine levels 47 and an increased ratio of kynurenine and tryptophan. 48,49 Other metabolites are synthesized exclusively by gut microbes and not endogenously produced by the host.…”

In Vitro Modulatory Effect of Stevioside, as a Partial Sugar Replacer in Sweeteners, on Human Child Microbiota

“…Although elevated levels of phenolic acids such as benzoic acid, hydroxyphenyllactic acid, and phenyl lactic acid could not be directly correlated with bacterial strains of the microbiota in the experimental system, they may be indicators for future in vivo studies on the effect of stevioside on the microbiota. These claims are supported by research linking the microbiota and phenyl carboxylic acid levels with hepatic steatosis and fibrosis [64], severity and mortality in critically ill patients [62], and sepsis [65].…”

“…While benzoic acid has a prooxidant effect, hydroxyphenyllactic acid and phenyllactic acid play an important role in lowering free radical concentration at the cellular level by acting as natural antioxidants [61]. These phenylcarboxylic acids appear to have bioregulatory effects both in the microbiota and whole organisms [62,63]. Although elevated levels of phenolic acids such as benzoic acid, hydroxyphenyllactic acid, and phenyl lactic acid could not be directly correlated with bacterial strains of the microbiota in the experimental system, they may be indicators for future in vivo studies on the effect of stevioside on the microbiota.…”