Table 3.
Effects of green tea and it’s components on diabetes in animal studies
| Treatment features | Model | Effects | Reference |
|---|---|---|---|
| EGCG 10 mg/kg/day in drinking water GTE 10 mg/kg/day in drinking water |
Mice administered 30% glucose | No significant effect on FBG, IPGTT, gAUC, insulin resistance, and HOMA-B, increasing insulin level | (146) |
| GTE in diet in 3 regimens: GTE 1g/kg of diet for 3 days,GTE 1g/kg of diet for 28 days,GTE 0.1g/kg of diet for 28 days |
Glutamate induced obese mice | No effect on anti-oxidation systems, a significant reduction in insulin level | (144) |
| Green tea polyphenon E 0.1% in the diet for 7 weeks | db/db mice (leptin deficiency model) | Decreased FBG, increased insulin level | (145) |
| EC 20 mg/kg in the diet for 15 weeks | HFD-induced insulin resistance in mice | Improved insulin sensitivity | (97) |
| EC 2-20 mg/kg | HFD-induced insulin resistance in mice | Attenuation of insulin resistance | (107) |
| GTE 2% in the diet for 8 weeks | RGS10 knockout mice fed a HFD | Regulation of impaired glucose tolerance test and insulin resistance | (100) |
| EC 0.5% in drinking water | Non-obese diabetic mice | Increased plasma insulin level, decreased HbA1C concentrations | (109) |
| EGCG 0.05% in drinking water | Non-obese diabetic mice | Increased plasma insulin level, decreased HbA1C concentrations | (147) |
| EGCG 10, 20 and 40 mg/kg/day IP for 4 weeks | non-alcoholic fatty liver disease (NAFLD) mice | Mitigation of hyperglycemia, hyperinsulinemia, and insulin resistance in a dose-dependent manner | (110) |
| EGCG 50 mg/kg/day for 10 weeks | Mice fed HFD | Improved insulin sensitivity and glucose tolerance | (101) |
| EGCG supplementation for 12 weeks | senescence-accelerated mice (SAM) prone 8 (SAMP8) | Improved insulin sensitivity by attenuating BG and insulin level | (98) |
| GT 500 mg/kg for 12 weeks | HFD fed mice | Improved insulin sensitivity | (102) |
| EGCG 25 or 75 mg/kg i.p 3times/week for 17 weeks | HFD fed C57BL/6 mice | Remarkably reduced plasma glucose and insulin level | (69) |
| EC 200 mg/kg in diet | HFD fed C57BL/6 mice | Protection from insulin resistance | (79) |
| EGCG 1 or 10 μM in drinking water at embryonic day 5.5 | Diabetic pregnant mice | EGCG 10 μM remarkably reduced neural tube defect incidence | (111) |
| FGT extract | Diet-induced obese mice | Decreased glucose intolerance | (67) |
| GT added to the diet | Diet-induced obese mice | Reduced BG and insulin levels | (81) |
| EGCG oral administration for 30 days | Diet-induced obese mice | Decreased serum glucose | (82) |
| GTE | Monosodium glutamate treated mice model | Decreased insulin levels | (80) |
| GTE 1 or 2 g/kg in the diet for 6 weeks | HFrD fed rats | Decreased glucose an insulin level, improved insulin resistance | (103) |
| Functional drinks containing catechins and EGCG | High cholesterol and high sucrose diet-fed rats | Mitigation of serum glucose and insulin levels | (73) |
| EGCG 3.2 g/kg in the diet for 16 weeks | HFD fed rats | Decreased fasting plasma insulin and homeostasis model assessment-insulin resistance index, increased glucose infusion rate | (148) |
| EC 20 mg/kg in the diet for 8 weeks | HFrD fed rats | Attenuation of insulin resistance | (96) |
| GT ad libitum for up to 90 days | T1D rats | Mitigation of periodontal breakdown and prevention of vascular disturbances | (149) |
| EGCG 50 mg/kg/day orally for 2 months | IDDM rats | Increased cardiac function synergistically with stem cell treatment | (150) |
| EGCG | Streptozotocin and HFD induced diabetic rats | Significant reduction in the expression and activity of P-glycoprotein | (151) |
| GT + GTC 30 or 100 mg | T2D rats | Decreased serum glucose level (more severe in GT+100 mg GTC) | (140) |
| GT in drinking water for 21 days | Streptozotocin-induced diabetic rats | Reduced hyperglycemia | (152) |
| GTE 200 mg/kg orally for 16 weeks | Streptozotocin-induced diabetic rats | Reduced BG and Hba1c level | (108) |
| GTE 0.75% or 1.0% in diet | HFD fed rats born of obese dams | Reduced insulin resistance in offspring | (141) |
| EGCG IV infusion with intralipid-heparin for 48 hours | Over-night fasted rats | Remarkably prohibited free fatty acid-induced peripheral insulin resistance | (153) |
| EGCG 2g/l as a beverage for 10 weeks | Streptozotocin-induced diabetic rats | Prevention of diabetes-induced loss of cavernous smooth muscle with no effect on vascular growth factor expression | (154) |
| GTP 200 mg/kg/day in drinking water for 6 weeks | HFrD fed rats | Mitigation of blood glucose and plasma insulin, improved insulin signaling | (104) |
| EGCG 25 mg/kg/day for 8 weeks | Streptozotocin-induced diabetic rats | Reduced glucose level | (105) |
| EGCG 1 or 10 mu mol/L | Day-9 rat conceptuses cultures | Attenuation of vasculopathy and malformations induced by hyperglycemia | (99) |
| Green tea ethanolic extract and powder – 8 weeks | Hyperglycemic rats | Reduced serum glucose level | (42) |
| GTP in drinking water | Diet-induced obese rat | Reduced BG, insulin resistance | (62) |
| GT 500 mg/kg/day, 5days/week for 12 weeks | Diet-induced obese rat | Restpred insulin sensitivity | (70) |
| GTC 150 or 300 mg/kg/day in the diet for 4 weeks GTC 20 mg/kg/day in diet for 45 days |
HFD fed KK-ay and C57BL/6 mice HFD fed rats |
Attenuated glucose level and enhanced glucose tolerance | (106) |
FGT: fermented green tea; EC: epicatechin; EGCG: epigallocatechin gallate; GT: green tea; GTE: green tea extract; GTP: green tea polyphenols; GTC: green tea catechin; HFD: high-fat diet; RGS10: Regulator of G-protein Signaling 10; HFrD: high fructose diet; T1D: type-1 diabetes; T2D: type-2 diabetes; IDDM: Insulin-dependent diabetes mellitus; BG: blood glucose; FBG: fasting blood glucose; HOMA: homeostatic model assessment; IPGTT: intraperitoneal glucose tolerance test; gAUC: glucose area under the curve; Hba1c: glycosylated hemoglobin A1c