Table 1.
Selected microbial associated metabolites from the human microbiota
| Metabolite | Related bacteria | Body site | Potential functions |
|---|---|---|---|
| Antimicrobial | |||
| Ruminococcin A, microcin, clostridiolysin S, zwittermicin, cytolysin, epidermin | Ruminococcus gnavus, Escherichia coli, Clostridium sporogenes, Bacillus cereus∗, Enterococcus faecalis, Staphylococcus epidermidis, Streptococcus pyogenes | Gut | Inhibit the growth of pathogens, promote commensal colonization in gut |
| Lactocillin | Lactobacillus gasseri | Vagina | Antibacterial peptide, inhibit the growth other pathogens |
| Epidermin | Staphylococcus epidermidis | Skin | Antimicrobial peptide |
| SA-FF22 | Streptococcus pyogenes | Skin/oral | Antimicrobial peptide |
| Streptolysin | |||
| Tilivalline | Klebsiella oxytoca | Gut | Peptide, cytotoxic |
| Cereulide | Bacillus cereus | Gut | Cytotoxic |
| Staphyloxanthin | Staphylococcus aureus | Skin | Virulence factor |
| Mycolactone | Mycobacterium ulcerans | Skin | Polyketide, cytotoxic |
| Immunomodulatory | |||
| α-Galactosylceramide | Bacteroides fragilis | Gut | Essential for myelin synthesis, Stimulate host immune systems |
| Short-chain fatty acids: propionic acid, acetate, butyrate, indolepropionic acid |
Bacteroides spp., Clostridium spp., Eubacterium spp., Butyrivibrio, Faecalibacterium spp., Clostridium sporogenes | Gut | Modulate host immune system, Energy to epithelial cells |
| Vitamins: Vitamin K, vitamin B12, biotin, folate, riboflavin, etc. |
Bifidobacterium spp., Propionibacterium freudenreichii, Salmonella enterica, Listeria innocua, Enterobacter spp. | Gut | Sources of vitamins, stimulate immune system, Exert epigenetic effects |
| Lipids: LPS, peptidoglycan, acylglycerols, triglycerides, Polysaccharide A |
Bifidobacterium spp. Roseburia, Lactobacillus, Clostridium spp., Bacillus fragilis | Gut | Induce inflammation, Enhance immune system, influence gut permeability |
| Polyamines: Putrescine, cadaverine, spermine |
Campylobacter jejuni, Clostridium saccharolyticum | Gut | Modulate immune system, anti-inflammatory and antitumoral effects |
| Bile acids: Cholate, muricholate, etc. |
Lactobacillus spp., Bifidobacterium spp., Clostridium spp., Bacteroides | Gut | Influence intestinal permeability |
| Muramyl dipeptides and tripeptides | Fusobacterium nucleatum | Oral | Modulate immune system |
| Siderophore | |||
| Corynebactin | Corynebacterium spp. | Skin | Peptide, Siderophore |
| Staphyloferrin B | Staphylococcus aureus | Skin | Peptide, Siderophore |
| Neurotransmitter | |||
| D-lactate Ammonia Acetyl-choline, Gamma-amino Butyrate, acetylcholine, Norepinephrine, serotonin, Dopamine |
Lactobacillus spp., Enterobacter spp., Bacillus spp. |
Gut | Influence blood-brain barrier, Neurotoxic |
| Lactobacillus spp., Bifidobacterium spp. Escherichia spp., Streptococcus spp., Bacillus spp. | Gut | Influence human hormones, Neurotransmitter, Influence human behaviors |
|
| Unknown functions | |||
| Skatole, p-cresol, phenyllactic acid, listeriolysin S, clostridiolysin S, δ-aminovaleric acid, β-aminoisobutyric acid | Clostridium spp., Bifidobacterium spp., Listeria monocytogenes, C. sporogenes, Clostridium spp. | Gut | Unknown |
| Mutanobactin, coproporphyrin III, corynomycolic acid | Streptococcus mutans, Propionibacterium acnes, Corynebacterium spp. | Mouth/skin | Unknown |