Effect of alcoholic extracts of Indian medicinal plants on the altered enzymatic activities of diabetic rats

Syringic Acid Ameliorates Cardiac, Hepatic, Renal and Neuronal Damage Induced by Chronic Hyperglycaemia in Wistar Rats: A Behavioural, Biochemical and Histological Analysis

This study investigated the effects of syringic acid (SA) on renal, cardiac, hepatic, and neuronal diabetic complications in streptozotocin-induced neonatal (nSTZ) diabetic rats. STZ (110 mg/kg i.p) was injected into Wistar rat neonates as a split dose (second and third postnatal day). Diabetes mellitus was diagnosed in adults by measuring fasting blood glucose levels, urine volume, and food and water intake. The treatment of SA (25 mg/kg, 50 mg/kg p.o) was given from the 8th to 18th postnatal week. To assess the development of diabetic complications and the effect of therapy, biochemical indicators in serum and behavioural parameters were recorded at specific intervals during the study period. SA (25 mg/kg, 50 mg/kg p.o) treatment reduced hyperglycaemia, polydipsia, polyphagia, polyuria, relative organ weight, cardiac hypertrophic indices, inflammatory markers, cell injury markers, glycated haemoglobin, histopathological score, and oxidative stress, and increased Na/K ATPase activity. These findings suggest that SA might significantly alleviate diabetic complications and/or renal, neuronal, cardiac, and hepatic damage in nSTZ diabetic rats.

Differential anti-diabetic effects and mechanism of action of charantin-rich extract of Taiwanese Momordica charantia between type 1 and type 2 diabetic mice

Momordica charantia Linn. (Cucurbitaceae), also called bitter melon, has traditionally been used as a natural anti-diabetic agent for anti-hyperglycemic activity in several animal models and clinical trials. We investigated the differences in the anti-diabetic properties and mechanism of action of Taiwanese M. charantia (MC) between type 1 diabetic (T1D) and type 2 diabetic (T2D) mice. To clarify the beneficial effects of MC, we measured non-fasting glucose, oral glucose tolerance, and plasma insulin levels in KK/HIJ mice with high-fat diet-induced diabetes (200 mg/kg/day of charantin-rich extract of MC [CEMC]) and in ICR mice with STZ-induced diabetes. After 8 weeks, all the mice were exsanguinated, and the expression of the insulin-signaling-associated proteins in their tissue was evaluated, in coordination with the protective effects of CEMC against pancreatic β-cell toxicity (in vitro). Eight weeks of data indicated that CEMC caused a significant decline in non-fasting blood glucose, plasma glucose intolerance, and insulin resistance in the KK/HIJ mice, but not in the ICR mice. Furthermore, CEMC decreased plasma insulin and promoted the sensitivity of insulin by increasing the expression of GLUT4 in the skeletal muscle and of IRS-1 in the liver of KK/HIJ mice; however, CEMC extract had no effect on the insulin sensitivity of ICR mice. In vitro study showed that CEMC prevented pancreatic β cells from high-glucose-induced cytotoxicity after 24 h of incubation, but the protective effect was not detectable after 72 h. Collectively, the hypoglycemic effects of CEMC suggest that it has potential for increasing insulin sensitivity in patients with T2D rather than for protecting patients with T1D against β-cell dysfunction.

Scientific validation of the antidiabetic effects of Syzygium jambolanum DC (black plum), a traditional medicinal plant of India

BACKGROUND

In spite of the tremendous progress achieved in medical sciences in the last century, the management of diabetes mellitus, a disease as old as mankind, is poor. Diabetes is currently the world's largest endocrine disorder, and estimates are that it affects almost 5% of the population. Ayurveda, the Indian traditional system of medicine, is one of the world's oldest systems to have documented the diagnosis and treatment of diabetes.

METHODS

Experimental studies performed in accordance with the modern medicine principles have shown that some of the medicinal plants and polyherbal preparations made using the plants used in Ayurveda are effective in preventing both hyperglycemia and its complications. Syzygium jambolanum (Syn Syzygium cumini, Eugenia cumini, Eugenia jambolana), commonly known as black plum and originally indigenous to India, is one of the important antidiabetic plants.

RESULTS

Jamun has been used in various complementary and alternative systems of medicine and, before the discovery of insulin, was a frontline antidiabetic medication even in Europe. The brew prepared by boiling the Jamun seeds in boiling water has been used in the various traditional systems of medicine in India.

CONCLUSIONS

This review includes the validated antidiabetic effects of Jamun and some of its compounds. Emphasis is also placed on addressing the various mechanisms of action contributing to the pharmacological effects and the aspects that need future investigations for Jamun to be of clinical use.