Therapeutic Potential of Polyphenols in the Management of Diabetic Neuropathy

Table 2

Antidiabetic properties of naturally occurring phenolic compounds.

Naturally occurring phenolic compounds	Effects	References
Flavonoids	(i) Intestinal microbiota ↑; (ii) Digestive enzymes ↓; (iii) Glucose absorption ↓; (iv) Formation of advanced glycation end products (AGEs) ↓	[27–31]
Catechins	(i) Insulin sensitivity ↑; (ii) Fecal excretion of bile acids and cholesterol ↑; (iii) Activation of AMPK ↑; (iv) White fat depots ↓; (v) Blood lipid ↓; (vi) Glycaemia ↓; (vii) Pancreatic α-glucosidase and also α-amylase and maltase ↓; (viii) Generation of reactive oxygen species ↓; (ix) Na^+-dependent glucose transporter ↓	[32–38]
Caffeoylquinic acids	(i) Insulin response ↑; (ii) Hepatic glucose-6-phosphatase ↓; (iii) Human pancreatic and salivary α-amylase ↓	[39–43]
Isoflavones	(i) Hypoglycemic effects through ameliorating insulin resistance and sensitivity ↑; (ii) Exerting anti-inflammation property ↑; (iii) Digestion of carbohydrate and uptake of glucose in the small intestine ↓; (iv) Protecting pancreatic β-cells ↑; (v) The mechanism of renal interstitial fibrosis in diabetic nephropathic rat models ↓; (vi) Oxidative damage ↓; (vii) Maillard reaction and formation of AGEs ↓	[44–46]
Hydroxycinnamic acids	(i) Insulin resistance and glucose intolerance ↑; (ii) Glucokinase activity ↑; (iii) β-Cell activity ↑; (iv) Antioxidant properties and anti-inflammatory activities ↑; (v) Activation of AMP-activated protein kinase ↑; (vi) Phosphoenolpyruvate carboxykinase and glucose-6-phosphatase effects in the liver ↓; (vii) Gluconeogenesis and adipogenesis ↓	[47–50]
Stilbenoids	(i) Metabolic control ↑; (ii) Pancreatic β-cell and hepatoprotective activity ↑; (iii) Insulin sensitivity ↑; (iv) DNA integrity ↑; (v) Level of digestive enzymes ↓; (vi) Oxidative stress and inflammation ↓	[51–57]
Tannins	(i) Uptake of glucose in adipose tissue through phosphorylation of IRS-1 ↑; (ii) Phosphorylation of AMPK ↑; (iii) Formation of AGEs and enzymatic action of sucrose, lactase, and maltase ↓; (iv) Activities of α-amylase and α-glucosidase ↓	[35, 58, 59]
Procyanidins	(i) Target digestive enzymes ↓; (ii) AMPK and insulin signaling pathways ↑; (iii) Cellular expression of NAD^+ and SIRT1 levels ↑; (iv) Proinflammatory cytokine expression ↓	[60–63]
Anthocyanins and anthocyanidins	(i) Antioxidant ↑; (ii) Blood glucose regulation ↑; (iii) Anti-inflammatory activity ↑; (iv) Oxidative damage ↓; (v) Concentrations of cholesterol, low-density cholesterol, and triglycerides ↓	[64–67]
Curcumin	(i) Protecting pancreatic β-cells ↑; (ii) Diabetic cardiomyopathy ↓; (iii) Insulin resistance ↓; (iv) Oxidative damage ↓	[44, 68–70]

Note: ↑ = induction; ↓ = inhibition.