| Lactobacillus casei Shirota | Patient study (RCT) | Improved bowel movements and reduced gastrointestinal symptoms in PD patients | (Cassani et al., 2011) |
| Lactobacillus acidophilus & Bifidobacterium infantis | Patient study (RCT) | Alleviated abdominal pain and bloating | (Georgescu et al., 2016) |
| Probiotic mix (L. acidophilus, B. bifidum, L. reuteri, L. fermentum) | Patient study (RCT) | Reduced MDS-UPDRS scores (Movement disorders society-unified parkinson’s disease rating scale) | (Tamtaji et al., 2019) |
| Bifidobacterium bifidum, Bifidobacterium longum, Lactobacillus rhamnosus, L. plantarum, Lactococcus lactis subsp. lactis | MitoPark PD mice | Improved motor function and reduced nigral dopaminergic neuronal degeneration in transgenic PD mice | (Hsieh et al., 2020) |
| Lactobacillus rhamnosus GG, Bifidobacterium animalis lactis, Lactobacillus acidophilus | Mouse model | Increased butyrate production and neuroprotection in MPTP and rotenone models. | (Srivastav et al., 2019) |
| SLAB51 (multi-strain mix) | In vitro + Mouse model | Neuroprotection through anti-inflammatory and antioxidant pathways and behavioral improvement | (Castelli et al., 2020) |
| Lactococcus lactis subsp. cremori (engineered strain with GLP-1) | Mouse model | Improved dopaminergic neurons and reduced locomotor impairment; boosted beneficial gut microbiota, reduced proinflammatory molecules | (Fang et al., 2019) |
| Bacillus subtilis PXN21 | C. elegans Model | Reduced α-synuclein aggregation and enhanced clearance of aggregates via alterations in sphingolipid metabolism | (Goya et al., 2020) |
| Lactobacillus spp. and Bifidobacterium spp. | In vitro (Blood cells from PD patients) | Modulation of inflammatory cytokines and inhibition of pathogenic bacteria growth | (Magistrelli et al., 2019) |
| Multi-strain mix and prebiotic fibers | Patient study (RCT) | Enhanced stool consistency, frequency, and quality of life in PD-related constipation. | (Barichella et al., 2016) |
| Probiotics mixture | Patient study (RCT) | Reduced overall disease severity related to constipation in PD patients | (Tan et al., 2021) |
| B. longum 1714, B. breve 1205 | Mouse model | Enhanced spatial and non-spatial memory, reduced visceral pain | (Savignac et al., 2015) |
| Lactobacillus acidophilus, L. reuteri, Bifidobacterium bifidum, L. fermentum | Male Wistar rats | Improved rotational behavior, cognitive function and neuronal damage | (Alipour Nosrani et al., 2021) |
| Bifidobacterium breve A1 | Mouse model | Restored hippocampal synaptic plasticity, reversed CA1 spine density decline, and improved contextual fear extinction | (Ishii et al., 2021) |
| Streptococcus thermophilus CRL 808, L. plantarum CRL 2130, S. thermophilus CRL 807 | Mouse model | Increased TH-positive cell counts, reduced inflammatory cytokines, and elevated anti-inflammatory IL-10 in brain | (Perez Visñuk et al., 2020) |
| Clostridium butyricum | Mouse model | Ameliorated synaptic dysfunction, improved dopaminergic neuron loss, motor function and reversed gut microbiota dysbiosis | (Sun et al., 2021) |
| Lacticaseibacillus rhamnosus HA-114 | Mouse model | Improved hippocampal-dependent cognition deficits | (Xie & Prasad, 2020) |