Bitter Melon Extracts in Diabetic and Normal Rats Favorably Influence Blood Glucose and Blood Pressure Regulation

Abstract

Bitter melon (BM) was tested in normal and streptozotocin (STZ)-induced diabetic rats. First, normal and diabetic Wistar rats were given four test extracts (EX-1-EX-4) of a wild-genotype BM or metformin by intubation. Second, normal Sprague-Dawley rats were divided into control and three test groups given for 52 days one of three BM preparations in food: Chinese or Indian commercial preparations or EX-4 from experiment I. In experiment I, extracts of BM administered at 50 mg/kg of body weight in normal rats reduced blood sugar for 4 hours without, unlike metformin, inducing hypoglycemia. In STZ-induced diabetic rats, two extracts administered at 250 mg/kg decreased glucose levels to values comparable to metformin at 150 mg/kg. At 4 hours, EX-1 and EX-4 significantly reduced blood glucose 67% and 63%, respectively, compared with metformin's 54%. In experiment II, all test groups had lowered systolic, but not diastolic, blood pressure. The China and EX-4 arms had significantly lowered serum glucose levels compared with the control. In the glucose tolerance test, only EX-4 had significantly lowered glucose levels. Only EX-4 had significantly lowered angiotensin converting enzyme (ACE) activity. All active arms showed significance in the losartan challenge (the renin-angiotensin system [RAS]), with the greatest effect in the EX-4 group. In the N(ω)-nitro-l-arginine-methyl ester challenge, only EX-4 exhibited a significant impact on the nitric oxide system, suggesting higher activity in this group. In the STZ-induced diabetic rat model, wild-type BM powerfully lowered glucose levels, and, in healthy adult rats, wild-type BM exhibited beneficial effects in the regulation of blood glucose, in RAS and ACE inhibition, and in nitric oxide generation.

Exendin-4 Protected against Cognitive Dysfunction in Hyperglycemic Mice Receiving an Intrahippocampal Lipopolysaccharide Injection

“…During continuous EX-4 treatment, we found that EX-4 decreased blood glucose and increased the insulin level in the hyperglycemic mice, which is consistent with some previous studies [50], [51]. In addition, in this study, EX-4 treatment also transiently increased IL- 1β in the normoglycemic mice and decreased IL-1β in the hyperglycemic mice.…”

Kuguacin J, a Triterpenoid from Momordica charantia Linn: A Comprehensive Review of Anticarcinogenic Properties

“…The whole extract of the fruit is also advocated in the treatment of diseases of the spleen, liver, and in rheumatism and gout [25]. An active ingredient from this plant has been used in diabetes mellitus [6,11,26]. In KwaZulu-Natal, the Zulus drink a concoction of the root or leaf for the treatment of boils and take an infusion of the runner as a sedative for an irritable stomach [27].…”

“…In addition, several compounds from bitter melon have shown interesting pharmacological activities, including antitumor, immunotoxic and anti-HIV properties, which merit further research, and may have strong potential in the development of future medicines [2,[6][7][8][9]. Although different types of synthetic drugs are available for the treatment of chronic diseases, such as diabetes and cancer, the synthetic agents in use can produce serious side effects and toxicity.…”

Personalized Diabetes and Cancer Medicine: A Rationale for Anti-Diabetic Nutrition (Bitter Melon) in a Supportive Setting

“…Antidiabetic effects of Bitter Melon extracts in insulin-resistant db/db mice could be attributed to the activity of a saponin and lipid fraction of the whole extract, which reduced the activity of tyrosine phosphotase 1B in skeletal muscle cell cytosol by 25% [38], explaining one possible biochemical mechanism underlying the antidiabetic effect in insulin resistance and type 2 diabetes. Moreover, the administration of 50mg/kg of body weight of Bitter Melon extract in normal rats reduced blood sugar for 4 hours without, unlike metformin, inducing hypoglycemia [41]. In diabetic rats Bitter Melon maintains normal glucose levels and lipid profiles when the rats where subjected to chronic sucrose load [40].…”