Ayurvedic Herbs That Lower Blood Glucose
Blood glucose control is a carefully orchestrated process carried out primarily by the actions of just two organs: the liver and pancreas; however, the system is sensitive to a wide network of external factors and internal feedback mechanisms. Ayurveda, one of the oldest known systems of medicine, utilizes specific medicinal herbs and herbal combinations to gently assist the body in maintaining healthy, balanced blood glucose levels. The following brief overview, organized according to specific actions, describes some of the many ways ayurvedic medicinal herbs lower blood glucose and illustrates how these actions may complement one another to achieve a particular effect.
Reducing Intestinal Glucose Absorption
One of the best ways to lower blood glucose is to not absorb it in the first place. During the transition to a low glycemic diet there are several ayurvedic herbs that can help decrease the absorption of carbohydrates.
• Momordica charantia, or bitter melon, decreases glucose absorption by reducing Na/K-dependent glucose transport into intestinal mucosal cells. Bitter melon also inhibits α-glucosidase, an enzyme in the intestinal brush border that cleaves carbohydrate molecules to release glucose[1,2].
• Gymnema sylvestre is known widely for its ability to discourage sugar consumption by desensitizing sweet receptors. Gymnema also inhibits glucose absorption via its active compound, gymnemic acid, which is similar in structure to glucose and binds to glucose receptors in the intestinal lining, which competes with glucose and suppresses its absorption.
• Fenugreek is high in both soluble and insoluble fiber, which slows intestinal glucose absorption.
• Swertia chirata inhibits α-glucosidase and other sugar-degrading enzymes, including maltase, sucrase, isomaltase and aldose reductase.
• Azadirachta indica significantly inhibits α-glucosidase, which breaks disaccharides and starch molecules into glucose and the salivary starch-degrading enzyme α-amalase.
Improving Pancreatic Function
Over time, chronic stress on the pancreas can lead to degenerative changes in pancreatic cells. Several ayurvedic herbs have been shown to support pancreatic function by restoring the viability of damaged cells and improving the efficiency of insulin production and secretion.
• Momordica charantia increases insulin secretion by promoting regeneration of beta cells, increasing size of pancreatic islets, and increasing the size and number of beta cells[1,2,7]. Bitter melon also increases expression of Pdx1, a transcription factor that promotes beta cell development and maturation.
• Emblica Officinalis, commonly known as amla, has been found to stimulate insulin release from beta cells in both healthy individuals and type 2 diabetics. Ellagic acid, an active constituent of amla, increases the size and number of beta cells.
• Curcumin increases plasma insulin levels by promoting membrane depolarization of beta-cell membranes necessary for the release of insulin.
• Fenugreek contains the amino acid 4-hydroxyisoleucine, which increases insulin release in response to elevated blood glucose levels by activating the Akt pathway, an important signaling pathway involved with cellular growth and survival.
• Gymnema sylvestre has been found to lower blood glucose levels in Type 2 diabetics by increasing insulin secretion.
• Swertia chirata, commonly referred to simply as chirata, directly stimulates beta cells to release insulin by virtue of its active compound mangiferin. Chirata also promotes beta cell repair and regeneration.
• Tinospora cordifolia is known to promotes secretion of insulin from beta cells.
• Eugenia jambolana significantly increases insulin levels in laboratory animals.
Insulin-Preserving and Insulin-Like Effects
Some ayurvedic herbs have insulin-like effects that can reduce the burden on the pancreas to produce and secrete insulin while others are able to protect insulin post-production.
• Eugenia jambolana maintains circulating insulin levels by inhibiting insulinase activity in the liver and kidneys.
• Amla demonstrated insulin-like effects on cells in animal studies of type-1 diabetes.
• Swertia chirata is said to exert insulin-like effects by reducing glycated hemoglobin levels.
• Eugenia jambolana reduced glycosylated hemoglobin in both mildly diabetic and severely diabetic laboratory animals.
Increasing Insulin Sensitivity and Improving Glucose Tolerance
Cells respond to chronically elevated blood glucose levels by dismantling their insulin receptors and glucose transport machinery. Herbs that increase insulin sensitivity play an important part in reversing this trend by reconstituting insulin signaling pathways in a number of ways. By so doing, they increase glucose uptake and decrease circulating blood glucose levels.
• Momordica charantia active constituents improve insulin signaling by increasing levels of insulin receptor substrate proteins, enzymes, and glucose transport factors within cell membrane[1,14].
• Azadirachta indica is capable of increasing glucose uptake in the presence or absence of insulin.
• Picrorhiza kurroa improves glucose tolerance and lowers elevated fasting blood glucose levels without causing hypoglycemia in laboratory animals.
• Swertia chirata enhances utilization of glucose by peripheral tissues.
Regulation of Glucose Production, Storage, and Release
The network of regulatory pathways involved in moving glucose in and out of storage provides numerous junctures at which medicinal herbs act to help keep blood glucose levels within safe limits.
o Improving Glycolysis
The process of glycolysis extracts free energy from glucose which is converted into ATP that fuels metabolism and increases energy consumption, thereby lowering blood glucose levels. Through feedback mechanisms, glycolysis also stimulates glycogenesis in the liver, further lowering blood glucose.
Curcumin improves glycolysis by activating glycolytic enzymes.
Swertia chirata also activates glycolytic enzymes.
o Inhibition of Gluconeogenesis
The process of gluconeogenesis converts glucose stores in the liver to available glucose, which is then deposited into circulation, raising blood glucose levels. Curtailing gluconeogenesis keeps stored glucose in reserve until the circulating glucose is utilized.
Momordica charantia inhibits gluconeogenesis by inhibiting the enzyme glucose-6-bisphosphatase which prepares glucose for export from liver cells into the bloodstream, and by inhibiting fructose-1,6-phosphatase, which prepares fructose for entry into the glycolytic pathway.
Tinospora cordifolia inhibits glucose 6-phosphatase and fructose 1,6-diphosphatase in the liver and kidney.
o Inhibition of Glycogenolysis
This process cleaves glycogen in the liver and deposits the resulting glucose monomers into circulation. Inhibiting this process holds stored glucose in reserve while available, circulating glucose is used.
Tinospora cordifolia inhibits glycogenolysis.
Momordica charantia also inhibits glycogenolysis in experimental animals.
o Improved Glycogen Synthesis and Storage
Glycogen synthesis throughout the body, but most predominantly in the liver and skeletal muscles.
Tinospora cordifolia helps preserve glycogen stores in the liver and skeletal muscle.
Picrorhiza kurroa promotes glycogen storage in the liver by stimulating glycogen synthase and inhibiting glycogen phosphorylase.
Momordica charantia promotes glycogen storage by promoting mitochondrial function in liver cells.
Eugenia jambolana increased liver and skeletal muscle glycogen levels in severely diabetic laboratory animals by 25% and 29%, respectively.
Liver and Pancreas Protection
Anything that helps the liver and pancreas can indirectly improve their function and efficiency relative to glucose metabolism. Some ayurvedic herbs have shown particular protective effects for these organs.
• Momordica charantia has been shown to reduce elevated levels of the liver enzymes ALT, AST, and ALP[7,8].
• Eugenia jambolana demonstrably reversed histopathological changes in the liver, as well as the pancreas, aorta, and heart of experimental diabetic animals.
• Picrorhiza kurroa restored levels of liver enzymes AST and ALT, commonly elevated in diabetes, to nearly normal levels in laboratory animals.
• Azadirachta indica improves activity of catalase and superoxide dismutase and has shown free radical scavenging capacity as high as 70% in liver cells.
• Curcumin inhibits signaling molecules that promote inflammation and tissue destruction such as nuclear factor-kappa B (NF-κB) and thiobarbituric acid reactive substance (TBARS) and attenuates tumor necrosis factor alpha (TNF-α). Curcumin also increases pancreatic islet cell viability by inducing stress-ameliorating heat shock proteins and decreases production of reactive oxygen species by pancreatic islet cells without impairing their function.
Modulating expression of genes that control metabolism has significant downstream effects for maintaining blood sugar control.
• Momordica charantia activates transcription factors PPAR-α and PPAR-γ which influence the activity of genes involved in metabolic homeostasis. Activation of PPAR-α and PPAR-γ increases insulin sensitivity, improves fat production and breakdown, and reduces inflammation. Additionally, momordica charantia achieves these effects without the significant side effect profile of thiazolinediones (TZDs), a family of diabetes drugs that target PPAR-γ.
• Curcumin activates PPAR-γ and nuclear factor erythroid 2-related factor 2 (Nrf2), a transcription factor that regulates antioxidant activity, protecting cells from oxidative damage. Curcumin also activates a gene that suppresses production of the pancreatic hormone glucagon, which opposes insulin.
- Momordica charantia and type 2 diabetes: from in vitro to human studies. Curr Diabetes Rev, 2014. 10(1): p. 48-60 https://pubmed.ncbi.nlm.nih.gov/24295371/
- Momordica charantia Administration Improves Insulin Secretion in Type 2 Diabetes Mellitus. J Med Food, 2018. 21(7): p. 672-677 https://pubmed.ncbi.nlm.nih.gov/29431598/
- A systematic review of Gymnema sylvestre in obesity and diabetes management. J Sci Food Agric, 2014. 94(5): p. 834-40 https://pubmed.ncbi.nlm.nih.gov/24166097/
- 4-Hydroxyisoleucine from Fenugreek (Trigonella foenum-graecum): Effects on Insulin Resistance Associated with Obesity. Molecules, 2016. 21(11)
- Experimental Evaluation of antidiabetic activity of Swertia Chirata – Aqueous Extract. J Pub Health Med Res, 2013
- Azadirachta indica inhibits key enzyme linked to type 2 diabetes in vitro, abates oxidative hepatic injury and enhances muscle glucose uptake ex vivo. Biomed Pharmacother, 2019. 109: p. 734-743 https://pubmed.ncbi.nlm.nih.gov/30551526/
- PPARγ signaling and metabolism: the good, the bad and the future. Nat Med, 2013. 19(5): p. 557-66 https://pubmed.ncbi.nlm.nih.gov/23652116/
- Momordica charantia reverses type II diabetes in rat. J Food Biochem, 2019. 43(11): p. e13021 https://pubmed.ncbi.nlm.nih.gov/31441956/
- Effect of Amla fruit (Emblica officinalis Gaertn.) on blood glucose and lipid profile of normal subjects and type 2 diabetic patients. Int J Food Sci Nutr, 2011. 62(6): p. 609-16 https://pubmed.ncbi.nlm.nih.gov/21495900/
- Ellagic acid in Emblica officinalis exerts anti-diabetic activity through the action on β-cells of pancreas. Eur J Nutr, 2017. 56(2): p. 591-601 https://pubmed.ncbi.nlm.nih.gov/26593435/
- Curcumin and diabetes: a systematic review. Evid Based Complement Alternat Med, 2013. 2013: p. 636053 https://pubmed.ncbi.nlm.nih.gov/24348712/
- Tinospora cordifolia attenuates oxidative stress and distorted carbohydrate metabolism in experimentally induced type 2 diabetes in rats. J Nat Med, 2011. 65(3-4): p. 544-50 https://pubmed.ncbi.nlm.nih.gov/21538233/
- Hypoglycaemic and hypolipidemic effect of ethanolic extract of seeds of Eugenia jambolana in alloxan-induced diabetic rabbits. J Ethnopharmacol, 2003. 85(2-3): p. 201-6 https://pubmed.ncbi.nlm.nih.gov/12639741/
- Bioactives from bitter melon enhance insulin signaling and modulate acyl carnitine content in skeletal muscle in high-fat diet-fed mice. J Nutr Biochem, 2011. 22(11): p. 1064-73 https://pubmed.ncbi.nlm.nih.gov/21277185/
- Antidiabetic activity of standardized extract of Picrorhiza kurroa in rat model of NIDDM. Drug Discov Ther, 2009. 3(3): p. 88-92 https://pubmed.ncbi.nlm.nih.gov/22495535/
- Hypoglycaemic activity of Coccinia indica and Momordica charantia in diabetic rats: depression of the hepatic gluconeogenic enzymes glucose-6-phosphatase and fructose-1,6-bisphosphatase and elevation of both liver and red-cell shunt enzyme glucose-6-phosphate dehydrogenase. Biochem J, 1993. 292 ( Pt 1)(Pt 1): p. 267-70 https://pubmed.ncbi.nlm.nih.gov/8389127/
- An experimental evaluation of the antidiabetic and antilipidemic properties of a standardized Momordica charantia fruit extract. BMC Complement Altern Med, 2007. 7: p. 29 https://pubmed.ncbi.nlm.nih.gov/17892543/
- Supplementation with Hualian No. 4 wild bitter gourd (Momordica charantia Linn. var. abbreviata ser.) extract increases anti-fatigue activities and enhances exercise performance in mice. J Vet Med Sci, 2017. 79(6): p. 1110-1119