Herbals Used in the Management of Diabetes (Chakkarai Noi)
Many common herbs, berries and spices are known to be effective in the management of diabetes. Most of these herbs can be broadly classified into three categories: (1) Blood glucose managers; (2) Free radical managers; and (3) Pancreatic rejuvenators. These time-tested remedies have proven their efficacy over the years, but today people lack the knowledge of how these herbs interact within the human system. Most of these herbals have been studied scientifically, but the research outcomes almost never reach the public in a simplified way. This article attempts to shine light onto the physiological and pharmacological actions of a few commonly used herbs for the management of diabetes.
- 1. Acacia Arabica (Karuvela Maram)
This plant is found all over India mainly in a wild habitat. The plant extract acts as an anti-diabetic agent by releasing insulin.
- 2. Aegle marmelos (Vilvam)
Extract from the leaves of this plant improves digestion and reduces blood sugar, urea and serum cholesterol. Along with exhibiting hypoglycemic activity, this extract also prevents a peak rise in blood sugar at 1 hour in an oral glucose tolerance test.
- 3. Allium cepa (Vengayam)
Allium cepa has anti-hyperglycemic activity. It is also known to have antioxidant and hypolipidaemic activity. The sulfur containing amino acid from Allium cepa, S-methyl cysteine sulphoxide (SMCS) has been proven to significantly control blood glucose as well as lipids in serum and tissues, and normalize the activities of liver enzymes hexokinase, glucose 6-phosphatase and HMG Co A reductase. A single oral dose of 50 g of onion juice, given to diabetic patients, significantly controls post-prandial glucose levels.
- 4. Allium sativum (Vellai poondu)
Allicin, a sulfur-containing compound that is responsible for this herb’s pungent odour, has been shown to have significant hypoglycemic activity. The effect is thought to be due to increased hepatic metabolism, increased insulin release from pancreatic beta cells, and/or an insulin sparing effect. Paste of garlic, when consumed, is shown to significantly increase hepatic glycogen and free amino acid content, decreased fasting blood glucose and triglyceride levels in serum.
S-allyl cystein sulfoxide (SACS), the precursor of allicin and garlic oil, a sulfur containing amino acid, is shown to control lipid peroxidation better than allopathic medicines like glibenclamide and insulin. It also improves diabetic conditions. Apart from this, Allium sativum exhibits antimicrobial, anticancer and cardioprotective activities.
- 5. Aloe vera and Aloe barbadensis (Sotru Katrazhai and Katrazhai)
The aloe plant can be separated into two basic products: gel and latex. Aloe vera gel is the leaf pulp or mucilage, while aloe latex, commonly referred to as “aloe juice,” is a bitter yellow exudate from the outer skin of the leaves. Extracts of aloe gum effectively increase glucose tolerance. Long term use of exudates of Aloe barbadensis leaves have shown hypoglycemic effect, and prolonged doses of the bitter principle of the same plant also show hypoglycemic effect. This action of Aloe vera and its bitter principle is through stimulation of synthesis and/or release of insulin from pancreatic beta cells. Apart from this, Aloe vera also has an anti-inflammatory activity in a dose dependent manner and improves wound healing. Aloe vera and Aloe barbadensis are very similar, but barbadensis has a better yield for the yellow bitter exudates. Hence in Siddha, the A. vera is used for internal medicines and A. barbadensis for external medicines.
- 6. Azadirachta indica (Veppilai)
Extracts of this plant have shown anti-hyperglycemic activity due to increase in glucose uptake and glycogen deposition. Apart from having anti-diabetic activity, this plant also has anti-bacterial, antimalarial, antifertility, hepatoprotective and antioxidant effects.
- 7. Caesalpinia bonducella (Kaliccikkai)
Caesalpinia bonducella is widely distributed throughout the coastal region of India and used by the ethnic people of India for controlling blood sugar. It is a potent hypoglycemic for chronic type II Diabetes. It is also known to increase glycogenesis, thereby increasing liver glycogen content as well as blocking glucose absorption. This herb is also a hypolipidemic.
- 8. Capparis deciduas (Sirakkali)
Extracts of the fruit from this plant have significant hypoglycemic and hypolipidaemic effects. This extract also reduced lipid peroxidation in erythrocytes, the kidney and the heart. It is also found to reduce oxidative stress.
- 9. Coccinia indica (Kovai)
Dried extracts of Coccinia indica are shown to restore the activities of enzyme lipoprotein lipase (LPL) that reduces glucose-6-phosphatase and lactate dehydrogenase, which are usually raised in untreated diabetics. Use of C. indica leaves shows significant hypoglycemic effects and increased glucose tolerance.
- 10. Syzgium cumini (Naaval Pazham)
A decoction of kernels of Syzgium cumini is used as a household remedy for diabetes. This also forms a major constituent of many herbal formulations for diabetes due to the significant antihyperglycemic effect. This effect varies with different levels of diabetes. In mild diabetes (plasma sugar >180 mg/dl), it shows 73.51% reduction, whereas in moderate (plasma sugar >280 mg/dl) and severe diabetes (plasma sugar >400 mg/dl), it is reduced to 55.62% and 17.72% respectively. The pulp is a faster acting antihyperglyceamic than the seed.
- 11. Mangifera indica (Manga)
The leaves of this plant are used as an effective addition to the diet to prevent dietary glucose absorption. It does not reduce hyperglycemia, but prevents hyperglycemia. Hence it can be considered a good antidiabetic agent.
Momordica charantia (Paavakkai)
Momordica charantia is commonly used as an antidiabetic and antihyperglycemic agent. Extracts of fruit pulp, seed, leaves and the whole plant is shown to have a hypoglycemic effect. Polypeptide p, isolated from fruit, seeds and tissues of M. charantia, showed significant hypoglycemic effect when administered subcutaneously to humans. This may be because of inhibition of glucose-6-phosphatase besides fructose-1, 6-biphosphatase in the liver, and stimulation of hepatic glucose-6-phosphate dehydrogenase activities.
Ocimum sanctum (thulasi)
It is commonly known as Tulsi. Since ancient times, this plant is known for its medicinal properties. The aqueous extract of leaves of Ocimum sanctum showed a significant reduction in blood sugar level. This plant also showed antiasthmatic, antistress, antibacterial, antifungal, antiviral, antitumor, gastric antiulcer activity, antioxidant, antimutagenic and immunostimulant activities.
Phyllanthus amarus (Kizhanelli)
This is an herb with a height of up to 60 cm, from the family Euphorbiaceae. It is commonly known as kizhanelli. It is scattered throughout the hotter parts of India, mainly Deccan, Konkan and south Indian states. Traditionally it is used in diabetes therapeutics. Methanolic extract of Phyllanthus amarus was found to have potent antioxidant activity. This extract also reduces blood sugar. The plant shows anti-inflammatory, anti-mutagenic, anti-carcinogenic and anti-diarrheal activity.
Pterocarpus marsupium (vengai)
It is a deciduous, moderate to large, tree found in India mainly in hilly regions. Pterostilbene, a constituent derived from the wood of this plant causes hypoglycemia. The hypoglycemic activity of this extract is because of the presence of tannates in the extract. Flavonoid fraction from Pterocarpus marsupium has been shown to cause pancreatic beta cell regranulation. Marsupin, pterosupin and liquiritigenin obtained from this plant showed antihyperlipidemic activity. (−) Epicatechin, its active principle, has been found to be insulinogenic, enhancing insulin release and the conversion of proinsulin to insulin. Like insulin, (−) epicatechin stimulates oxygen uptake in fat cells and tissues in a dose-dependent manner.
Trigonella foenum graecum (Uluva)
This plant is found all over India, and the fenugreek seeds are usually used as one of the major constituents of Indian spices. 4-hydroxyleucine, a novel amino acid from fenugreek seeds, increases glucose stimulated insulin release. Oral intake of the plant extract can produce a dose dependent decrease in blood glucose levels. Administration of fenugreek seeds also improves glucose metabolism and normalizes creatinine kinase activity in heart, skeletal muscle and liver. It also reduces hepatic and renal glucose-6-phosphatase and fructose −1,6-biphosphatase activity. This plant shows significant antioxidant activity.
Tinospora cordifolia (Seenthil Kodi)
This is a large, glabrous, deciduous climbing shrub belonging to the family Menispermaceae. It is widely distributed throughout India and commonly known as Seenthi kodi. Oral administration of the extract of Tinospora cordifolia (T. cordifolia) root for 6 weeks results in a significant reduction in blood and urine glucose, and in lipids in serum and tissues. T. cordifolia is widely used in the Indian system of medicine for treating diabetes mellitus. The daily administration of extracts of T. cordifolia can decrease the blood glucose level and increases glucose tolerance.