Table 3.
Experimental evidence on the effects of microbial supernatants, extracts, and biosurfactants in diabetes mellitus.
| Type of Research | Component | Bioactive Molecule(s) | Source/Origin | Model System (If Apply) | Findings | Study |
|---|---|---|---|---|---|---|
| Animal | Supernatant | Supernatant | Lactobacillus rhamnosus GG | C57BL/6J induced metabolic dysfunction with HFFD and intermittent hypoxia | ↓ FBG (vs. baseline values), ↑insulin sensitivity, ↑ energy expenditure, improved body composition (fat and muscle mass), ↓ TC and TG, ↑ NEFAs, ↑ total faecal SFCAs, ↓ proinflammatory cytokines expression, downregulated lipogenesis, upregulated lipid oxidation | Liu et al., 2020 [103] |
| Extract | Fermented soybean extracts (served dried with corn starch), low and high doses | Bacillus subtilis MORI/Isolated from Chungkookjang | Wistar rats induced T1D with STZ (55 mg/kg) | Low and high doses (vs. diabetic controls): ↑ BW, attenuated rise in FBG, ↓ food and water intake, ↓ MDA serum levels, ↑ CAT and GSH-Px activity, improved vascular function High doses (vs. diabetic control): ↑serum insulin levels and SOD levels |
Lim et al., 2012 [102] | |
| Biosurfactant | Biosurfactant (served as crude lipopeptide preparation) | Bacillus subtilis SPB1/Isolated from Tunisian soil | Wistar rats induced T1D with alloxan (150 mg/kg) | ↓ FBG and α-amylase activity in the plasma, ↓ TC, TG, and LDL levels, ↑ HDL levels, protected tissues (pancreatic b cells, liver, intestine, and kidney) | Zouari et al., 2015 [104] | |
| Wistar rats induced T2D with HFFD | ↓FBG, improved glucose tolerance (OGTT), normalised serum α-amylase activity | Zouari et al., 2017 [105] | ||||
| In vitro | Supernatant | CFS | Five Lactobacillus plantarum strains: CCFM0236, CCFM 12, CCFM 10, CCFM0311, and CCFM 23 | - | α-glucosidase inhibitory activity (%): from 14.5 to 32.2 | Li et al., 2016 [107] |
| CFE and CFS | 8 LAB isolates (K1, K8, K16, K19, K29, K35, K45, K96, and LGG)/Isolated from commercial water kefir grains | - | α-glucosidase inhibitory activity (%): from 5.2 to 39.4 in CFS, from 2.3 to 15.5 in CFE | Koh et al., 2018 [108] | ||
| CFE, CFS and CFES | 14 Lactobacillus spp. strains/Isolated from traditional fermented products | - | DPP-IV inhibitory activity (%): from 0 to 55.4 in CFE, from 0 to 7.13 in CFES/reducing activity (mmol of cysteine): from 73.3 to 189.7 in CFS, from 53.0 to 159.7 in CFE/DPPH free radical-scavenging activity (%): from 36.8 to 62.1 in CFS, from 12.9 to 34.5 in CFE/hydroxyl radical scavenging activity: from 13.7 to 68.6 in CFS; from 15.9 to 38.8 in CFE/superoxide anion radical scavenging activity (%): from 2.6 to 16.2 in CFS; from 12.2 to 43.3 in CFE/lipid peroxidation inhibiting capacity (%): from 1.5 to 18.5 in CFS; from 5.9 to 31.4 in CFE. | Yan et al., 2020 [109] |
BW: body weight; CAT: catalase; CFS: cell-free supernatant; CFE: cell-free extract; CFES: cell-free excretory supernatants; DPP-IV: dipeptidyl peptidase IV; DPPH: 1,1-Diphenyl-2-Picryl-Hydrazyl; FBG: fasting blood glucose; GSH-Px glutathione peroxidase; HFFD: high-fat fructose diet; MDA: malondialdehyde; NEFAs: non-esterified fatty acid; OGTT: oral glucose tolerance test; SCFA: short-chain fatty acids; SOD: superoxide dismutase; UCP-1: uncoupling protein 1. ↑ means increase, ↓ means decrease