Bitter melon fruit extract enhances intracellular ATP production and insulin secretion from rat pancreatic β-cells

2021 ◽  
pp. 1-7
Author(s):  
Takumi Shimada ◽  
Fumihiro Kato ◽  
Dinia Rizqi Dwijayanti ◽  
Takuma Nagata ◽  
Akito Kinoshita ◽  
...  

Abstract Bitter melon (Momordica charantia L.) has been shown to have various health-promoting activities, including antidiabetic and hypoglycaemic effects. Improvement in insulin sensitivity and increase in glucose utilisation in peripheral tissues have been reported, but the effect on insulin secretion from pancreatic β-cells remains unclear. In this study, we investigated the effect of bitter melon fruit on insulin secretion from β-cells and the underlying mechanism. The green fruit of bitter melon was freeze-dried and extracted with methanol. The bitter melon fruit extract (BMFE) was fractionated using ethyl acetate (fraction A), n-butanol (fraction B) and water (fraction C). Insulin secretory capacity from INS-1 rat insulinoma cell line and rat pancreatic islets, as well as glucose tolerance in rats by oral glucose tolerance test (OGTT), was measured using BMFE and fractions. ATP production in β-cells was also examined. BMFE augmented insulin secretion from INS-1 cells in a dose-dependent manner. The significant augmentation of insulin secretion was independent of the glucose dose. Fraction A (i.e. hydrophobic fraction), but not fractions B and C, augmented insulin secretion significantly at the same level as that by BMFE. This finding was also observed in pancreatic islets. In OGTT, BMFE and fraction A decreased blood glucose levels and increased serum insulin levels after glucose loading. The decrease in blood glucose levels was also observed in streptozotocin-induced diabetic rats. In addition, BMFE and fraction A increased the ATP content in β-cells. We concluded that hydrophobic components of BMFE increase ATP production and augment insulin secretion from β-cells, consequently decreasing blood glucose levels.

2008 ◽  
Vol 294 (2) ◽  
pp. E217-E229 ◽  
Author(s):  
Shunzhong Bao ◽  
David A. Jacobson ◽  
Mary Wohltmann ◽  
Alan Bohrer ◽  
Wu Jin ◽  
...  

Studies with genetically modified insulinoma cells suggest that group VIA phospholipase A2 (iPLA2β) participates in amplifying glucose-induced insulin secretion. INS-1 insulinoma cells that overexpress iPLA2β, for example, exhibit amplified insulin-secretory responses to glucose and cAMP-elevating agents. To determine whether similar effects occur in whole animals, we prepared transgenic (TG) mice in which the rat insulin 1 promoter (RIP) drives iPLA2β overexpression, and two characterized TG mouse lines exhibit similar phenotypes. Their pancreatic islet iPLA2β expression is increased severalfold, as reflected by quantitative PCR of iPLA2β mRNA, immunoblotting of iPLA2β protein, and iPLA2β enzymatic activity. Immunofluorescence microscopic studies of pancreatic sections confirm iPLA2β overexpression in RIP-iPLA2β-TG islet β-cells without obviously perturbed islet morphology. Male RIP-iPLA2β-TG mice exhibit lower blood glucose and higher plasma insulin concentrations than wild-type (WT) mice when fasting and develop lower blood glucose levels in glucose tolerance tests, but WT and TG blood glucose levels do not differ in insulin tolerance tests. Islets from male RIP-iPLA2β-TG mice exhibit greater amplification of glucose-induced insulin secretion by a cAMP-elevating agent than WT islets. In contrast, islets from male iPLA2β-null mice exhibit blunted insulin secretion, and those mice have impaired glucose tolerance. Arachidonate incorporation into and the phospholipid composition of RIP-iPLA2β-TG islets are normal, but they exhibit reduced Kv2.1 delayed rectifier current and prolonged glucose-induced action potentials and elevations of cytosolic Ca2+ concentration that suggest a molecular mechanism for the physiological role of iPLA2β to amplify insulin secretion.


2019 ◽  
Vol 19 (3) ◽  
pp. 292-301
Author(s):  
Omar Farid ◽  
Naoufel Ali Zeggwagh ◽  
Fadwa EL Ouadi ◽  
Mohamed Eddouks

Objective: The aim of this work was to evaluate the antihyperglycemic activity of aerial parts aqueous extract (A.P.A.E) of Mentha pulegium (M. pulegium) on blood glucose levels in normal and streptozotocin(STZ)-induced diabetic rat. The glucose tolerance was evaluated in normal rats. Moreover, the histological sections and morphometric analysis at the liver and pancreas have been carried out in this investigation both in normal and STZ-diabetic rats. Methods: The effect of A.P.A.E of M. pulegium (20 mg/kg) on blood glucose levels was investigated in normal and diabetic rats (n=6). Histopathological changes in liver and pancreas were examined under phase contrast microscope and a preliminary screening for various bioactive constituents was realized according to standard methods. Key Findings: Both single and repeated oral administration of A.P.A.E (20 mg/kg) caused a significant reduction in blood glucose levels in STZ-diabetic rats (p<0.0001). The morphometric analysis and histological sections realized in pancreas and liver have showed the beneficial effect of the A.P.A.E in cellular population. According to oral glucose tolerance test (OGTT), the aqueous extract has revealed an improvement of glucose tolerance in normal rat. Furthermore, the preliminary phytochemical screening of A.P.A.E of M. pulegium has demonstrated the presence of various metabolite compounds including polyphenols, flavonoids, terpenoids tannins, cyanidins, sesquiterpenes, and glycosides. Conclusion: We conclude that the A.P.A.E of M. pulegium (20 mg/kg) exhibits a potent antihyperglycemic activity in STZ diabetic rats.


2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Samira Missaoui ◽  
Khémais Ben Rhouma ◽  
Mohamed-Tahar Yacoubi ◽  
Mohsen Sakly ◽  
Olfa Tebourbi

We examined the effects of vanadium sulfate (VOSO4) treatment at 5 and 10 mg/kg for 30 days on endocrine pancreas activity and histology in nondiabetic and STZ-induced diabetic rats. In diabetic group, blood glucose levels significantly increased while insulinemia level markedly decreased. At the end of treatment, VOSO4at a dose of 10 mg/Kg normalized blood glucose level in diabetic group, restored insulinemia, and significantly improved insulin sensitivity. VOSO4also increased in a dose-dependent manner the number of insulin immunopositive beta cells in pancreatic islets of nondiabetic rats. Furthermore, in the STZ-diabetic group, the decrease in the number of insulin immunopositive beta cells was corrected to reach the control level mainly with the higher dose of vanadium. Therefore, VOSO4treatment normalized plasma glucose and insulin levels and improved insulin sensitivity in STZ-experimental diabetes and induced beta cells proliferation and/or regeneration in normal or diabetic rats.


Endocrinology ◽  
2005 ◽  
Vol 146 (12) ◽  
pp. 5425-5432 ◽  
Author(s):  
Yan Ao ◽  
Natalie Toy ◽  
Moon K. Song ◽  
Vay Liang W. Go ◽  
Hong Yang

Insulin secretion is impaired in type 2 diabetes (T2D). The insulin and glucose responses to central autonomic activation induced by excitation of brain medullary TRH receptors were studied in T2D Goto-Kakizaki (GK) rats. Blood glucose levels in normally fed, pentobarbital-anesthetized GK and nondiabetic Wistar rats were 193 and 119 mg/100 ml in males and 214 and 131 mg/100 ml in females. Intracisternal injection (ic) of the stable TRH analog RX 77368 (10 ng) induced significantly higher insulin response in both genders of overnight-fasted GK rats compared with Wistar rats and slightly increased blood glucose in female Wistar rats but significantly decreased it from 193 to 145 mg/100 ml in female GK rats. RX 77368 (50 ng) ic induced markedly greater glucose and relatively weaker insulin responses in male GK rats than Wistar rats. Bilateral vagotomy blocked ic RX 77368-induced insulin secretion, whereas adrenalectomy abolished its hyperglycemic effect. In adrenalectomized male GK but not Wistar rats, ic RX 77368 (50 ng) dramatically increased serum insulin levels by 6.5-fold and decreased blood glucose levels from 154 to 98 mg/100 ml; these changes were prevented by vagotomy. GK rats had higher basal pancreatic insulin II mRNA levels but a lower response to ic RX 77368 (50 ng) compared with Wistar rats. These results indicate that central-vagal activation-induced insulin secretion is susceptible in T2D GK rats. However, the dominant sympathetic-adrenal response to medullary TRH plays a suppressing role on vagal-mediated insulin secretion. This unbalanced vago-sympathetic activation by medullary TRH may contribute to the impaired insulin secretion in T2D.


2015 ◽  
Vol 10 (2) ◽  
pp. 326 ◽  
Author(s):  
Emordi Jonathan Emeka ◽  
Agbaje Esther Oluwatoyin ◽  
Oreagba Ibrahim Adekunle ◽  
Iribhogbe Osede Ignis

<p>The purpose of this study is to evaluate the hypoglycaemic properties and preliminary phytochemical screening of <em>Uveria chamae</em>. The hypoglycaemic properties of <em>Uveria chamae</em> was assessed on normoglycaemic rat that received single dose of the extract at 250 and 500 mg/kg body weight and blood glucose levels estimated at 2, 4, and 6 hours (single dose study). The hypoglycaemic property of the extract was also evaluated in normoglycemic rats by oral glucose tolerance test. Phytochemical screening of the extract for the presence of secondary metabolites was performed with standard methods. The extract showed a significant (p&lt;0.05) reduction in blood glucose levels at 2h and 6h compared to control.  The oral glucose tolerance test  result also showed a significant decrease (p&lt;0.05) in blood glucose levels . The study showed that the extract, <em>Uveria chamae</em> has hypoglycaemic properties which may be accounted for by the presence of the phytochemicals.</p><p> </p>


2015 ◽  
Vol 58 (3) ◽  
pp. 259-265 ◽  
Author(s):  
Hye Seon Park ◽  
Woo Kyeong Kim ◽  
Hyun Pyo Kim ◽  
Young Geol Yoon

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