Table 1.

Experimental studies on microbial exopolysaccharides in diabetes mellitus.

Type of Research	Bioactive Component	Source/Origin	Model System	Main Findings	Study
Animal	Levan	Bacillus licheniformis	Wistar rats induced T1D with alloxan (150 mg/kg BW)	↓Glycaemia, ↑glycogen level, ↓AST, ALT, bilirubin, creatinine, and urea levels	Dahech et al., 2011 [83]
	Levan	Bacillus subtilis (Natto)	Wistar rats induced T1D with STZ (65 mg/kg BW)	No hypoglycaemic effect. No improvement of diabetes symptoms	Bazani et al., 2012 [88]
	Exopolysaccharide (unspecified)	Bacillus subtilis	Sprague-Dawley rats induced T1D with STZ (65 mg/kg BW)	↓FBG, ↑serum insulin levels, ↓TC, LDL, VLDL and TG, ↑HDL in treated vs. control rats	Ghoneim et al., 2016 [89]
	Selenium-enriched exopolysaccharide	Enterobacter cloacaceae Z0206	Female ICR mice induced T1D with alloxan (190 mg/kg)	↓FBG, ↑serum insulin level, ↓glycosylated serum protein, ↑BW, ↓TC and TG in treated vs. control mice	Jin et al., 2012 [26]
	Exopolysaccharide (unspecified)	Sorangium cellulosum NUST06	Mice (Kunming strain) induced T1D with alloxan (250 mL/kg BW)	↓FBG in both healthy and alloxan-induced diabetic mice	Ding et al., 2004 [91]
Cell line	Exopolysaccharide (unspecified)	Lactobacillus plantarum H31-2	In vitro, insulin-resistant HepG2 cells	↓Supernatant glucose concentration of insulin-resistant HepG2 cells, inhibition of pancreas α-amylase, upregulation of the expression of GLUT-4, Akt-2, and AMPK	Huang et al., 2020 [90]

ALT: alanine aminotransferase; AST: aspartate aminotransferase; BW: body weight; FBG: fasting blood glucose; ICR: Institute Cancer Research; HDL: high-density lipoprotein; LDL: low-density lipoprotein; STZ: streptozotocin; TC: total cholesterol; TG: triglyceride; T1D: type 1 diabetes; VLDL: very-low-density lipoprotein. ↑ means increase, ↓ means decrease.