| AD | Alzheimer’s disease |
| BDNF | Brain-derived neurotrophic factor |
| CNS | Central nervous system |
| CD14 | Cluster of differentiation 14 |
| DA | Dopaminergic |
| ENS | Enteric nervous system |
| EAE | Experimental autoimmune encephalomyelitis |
| FTD | Frontotemporal dementia |
| GSH | Glutathione |
| GABA | γ-aminobutyric acid |
| H2 | Hydrogen |
| HD | Huntington’s disease |
| HPA | Hypothalamic–pituitary–adrenal |
| H2S | Hydrogen sulfide |
| IBD | Inflammatory bowel disease |
| IBS | Irritable bowel syndrome |
| KYN | Kynurenine |
| MS | Multiple sclerosis |
| MPTP | 1-methyl-4-phenyl-1,2,3,4-tetrahydropyridine |
| NDs | Neurodegenerative diseases |
| NO | Nitric oxide |
| NFTs | Neurofibrillary tangles |
| PA | Proanthocyanidins |
| PD | Parkinson’s disease |
| p-JNK | phosphorylation-c-Jun N-terminal kinase |
| ROS | Reactive oxygen species |
| RNS | Reactive nitrogen species |
| SOD1 | Superoxide dismutase 1 |
| SCFAs | Short-chain fatty acids |
| SIRT1 | Sirtuin-1 |
| TLRs | Toll-like receptors |
| TH17 | T helper 17 |
| TUDCA | Taurine deoxycholic acid |