Mechanisms and Therapeutic Potential of Key Anti-inflammatory Metabiotics: Trans-Vaccenic Acid, Indole-3-Lactic Acid, Thiamine, and Butyric Acid.

Identifying metabolites produced by probiotic bacteria, also known as metabiotics, is becoming increasingly common due to their anti-inflammatory, anti-obesogenic, and immunomodulatory effects. Postbiotics alongside diet, regulate both physical and mental health, as the microbiota members can interact physically with host cells or through secretion of nutrients and metabiotics. These metabiotics also reduce the severity of certain metabolic disorders and support the proper functioning of various organs and systems. In this review, we describe the mechanisms of action of trans-vaccenic acid (TVA), indole-3-lactic acid (ILA), thiamine (vitamin B1), and butyric acid metabolites produced or induced by probiotics such as Lactobacillus and/or Bifidobacterium, among others and previously identified using analytical techniques such as mass spectrometry (LC-MS). Within their mechanisms of action, Trans-vaccenic acid exerts anti-inflammatory effects and helps alleviate complications associated with metabolic diseases. Indole metabolites promote IL-22 production and regulate epithelial cell proliferation and antimicrobial peptide production. Thiamin is essential for energy metabolism regulation, and butyric acid regulates the brain-gut axis and also regulates immune response. This review expands our understanding of the potential therapeutic use of metabiotics.