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Potential of Diterpenes as Antidiabetic Agents: Evidence from Clinical and Pre-Clinical Studies. Pharmacol Res 2022; 179:106158. [PMID: 35272043 DOI: 10.1016/j.phrs.2022.106158] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Revised: 02/18/2022] [Accepted: 03/03/2022] [Indexed: 11/20/2022]
Abstract
Diterpenes are a diverse group of structurally complex natural products with a wide spectrum of biological activities, including antidiabetic potential. In the last 25 years, numerous diterpenes have been investigated for antidiabetic activity, with some of them reaching the stage of clinical trials. However, these studies have not been comprehensively reviewed in any previous publication. Herein, we critically discussed the literature on the potential of diterpenes as antidiabetic agents, published from 1995 to September, 2021. In the period under review, 427 diterpenes were reported to have varying degrees of antidiabetic activity. Steviol glycosides, stevioside (1) and rebaudioside A (2), were the most investigated diterpenes with promising antidiabetic property using in vitro and in vivo models, as well as human subjects. All the tested pimaranes consistently showed good activity in preclinical evaluations against diabetes. Inhibitions of α-glucosidase and protein tyrosine phosphatase 1B (PTP 1B) activities and peroxisome proliferator-activated receptors gamma (PPAR-γ) agonistic property, were the most frequently used assays for studying the antidiabetic activity of diterpenes. The molecular mechanisms of action of the diterpenes include increased GLUT4 translocation, and activation of phosphoinositide 3-kinase (PI3K) and AMP-activated protein kinase (AMPK)-dependent signaling pathways. Our data revealed that diterpenes hold promising antidiabetic potential. Stevioside (1) and rebaudioside A (2) are the only diterpenes that were advanced to the clinical trial stage of the drug discovery pipeline. Diterpenes belonging to the abietane, labdane, pimarane and kaurane class have shown promising activity in in vitro and in vivo models of diabetes and should be further investigated.
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Apaya MK, Kuo TF, Yang MT, Yang G, Hsiao CL, Chang SB, Lin Y, Yang WC. Phytochemicals as modulators of β-cells and immunity for the therapy of type 1 diabetes: Recent discoveries in pharmacological mechanisms and clinical potential. Pharmacol Res 2020; 156:104754. [DOI: 10.1016/j.phrs.2020.104754] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/07/2019] [Revised: 03/07/2020] [Accepted: 03/10/2020] [Indexed: 12/19/2022]
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Assi AA, Abd El-hamid DH, Abdel-Rahman MS, Ashry EE, AI Bayoumi S, Ahmed AM. The Potential Efficacy of Stevia Extract, Glimepiride and Their Combination in Treating Diabetic Rats: A Novel Strategy in Therapy of Type 2 Diabetes Mellitus. EGYPTIAN JOURNAL OF BASIC AND CLINICAL PHARMACOLOGY 2020. [DOI: 10.32527/2020/101455] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Affiliation(s)
- Abdel-Azim Assi
- Department of Pharmacology, Faculty of Medicine, Assiut University, Assiut, Egypt
| | - Doaa H. Abd El-hamid
- Department of Pharmacology, Faculty of Medicine, Assiut University, Assiut, Egypt
| | | | - Esraa E. Ashry
- Department of Pharmacology, Faculty of Medicine, Assiut University, Assiut, Egypt
| | - Soad AI Bayoumi
- Department of Pharmacognosy, Faculty of Pharmacy, Assiut University, Assiut, Egypt
| | - Asmaa M. Ahmed
- Department of Pathology, Faculty of Medicine, Assiut University, Assiut, Egypt
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Yoneda Y, Nakashima H, Miyasaka J, Ohdoi K, Shimizu H. Impact of blue, red, and far-red light treatments on gene expression and steviol glycoside accumulation in Stevia rebaudiana. PHYTOCHEMISTRY 2017; 137:57-65. [PMID: 28215607 DOI: 10.1016/j.phytochem.2017.02.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Revised: 02/01/2017] [Accepted: 02/03/2017] [Indexed: 06/06/2023]
Abstract
Stevia rebaudiana (Bertoni) Bertoni is a plant that biosynthesizes a group of natural sweeteners that are up to approximately 400 times sweeter than sucrose. The sweetening components of S. rebaudiana are steviol glycosides (SGs) that partially share their biosynthesis pathway with gibberellins (GAs). However, the molecular mechanisms through which SGs levels can be improved have not been studied. Therefore, transcription levels of several SG biosynthesis-related genes were analyzed under several light treatments involved in GA biosynthesis. We detected higher transcription of UGT85C2, which is one of the UDP-glycosyltransferases (UGTs) involved in catalyzing the sugar-transfer reaction, under red/far-red (R/FR) 1.22 light-emitting diodes (LEDs) and blue LEDs treatment. In this study, it was demonstrated that transcription levels of SG-related genes and the SGs content are affected by light treatments known to affect the GA contents. It is expected that this approach could serve as a practical way to increase SG contents using specific light treatments.
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Affiliation(s)
- Yuki Yoneda
- Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto, 606-8502, Japan
| | - Hiroshi Nakashima
- Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto, 606-8502, Japan
| | - Juro Miyasaka
- Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto, 606-8502, Japan
| | - Katsuaki Ohdoi
- Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto, 606-8502, Japan
| | - Hiroshi Shimizu
- Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto, 606-8502, Japan.
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Aranda-González I, Segura-Campos M, Moguel-Ordoñez Y, Betancur-Ancona D. Stevia rebaudianaBertoni. Un potencial adyuvante en el tratamiento de la diabetes mellitus. CYTA - JOURNAL OF FOOD 2013. [DOI: 10.1080/19476337.2013.830150] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Hectors TLM, Vanparys C, Pereira-Fernandes A, Martens GA, Blust R. Evaluation of the INS-1 832/13 cell line as a beta-cell based screening system to assess pollutant effects on beta-cell function. PLoS One 2013; 8:e60030. [PMID: 23555872 PMCID: PMC3605429 DOI: 10.1371/journal.pone.0060030] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2012] [Accepted: 02/22/2013] [Indexed: 01/15/2023] Open
Abstract
Environmental pollutants have recently emerged as potential risk factors for metabolic diseases, urging systematic investigation of pollutant effects on metabolic disease processes. To enable risk assessment of these so-called metabolic disruptors the use of stable, robust and well-defined cell based screening systems has recently been encouraged. Since beta-cell (dys)functionality is central in diabetes pathophysiology, the need to develop beta-cell based pollutant screening systems is evident. In this context, the present research evaluated the strengths and weaknesses of the INS-1 832/13 pancreatic beta-cell line as diabetogenic pollutant screening system with a focus on beta-cell function. After optimization of exposure conditions, positive (exendin-4, glibenclamide) and negative (diazoxide) control compounds for acute insulin secretion responses were tested and those with the most profound effects were selected to allow potency estimations and ranking of pollutants. This was followed by a first explorative screening of acute bisphenol A and bis(2-ethylhexyl)phthalate effects. The same approach was applied for chronic exposures, focusing primarily on evaluation of acknowledged chronic stimulators (diazoxide, T0901317, exendin-4) or inhibitors (glibenclamide) of insulin secretion responses to select the most responsive ones for use as control compounds in a chronic pollutant testing framework. Our results showed that INS-1 832/13 cells responded conform previous observations regarding acute effects of control compounds on insulin secretion, while bisphenol A and bis(2-ethylhexyl)phthalate had limited acute effects. Furthermore, chronic exposure to known beta-cell reactive compounds resulted in deviating insulin secretion and insulin content profiles compared to previous reports. In conclusion, this INS-1 subclone appears to lack certain characteristics needed to respond appropriately to acute pollutant exposure or long term exposure to known beta-cell reactive compounds and thus seems to be, in our setting, inadequate as a diabetogenic pollutant screening system.
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Affiliation(s)
- Tine L M Hectors
- Systemic Physiological and Ecotoxicological Research, Department of Biology, University of Antwerp, Antwerp, Belgium.
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Barwal I, Sood A, Sharma M, Singh B, Yadav SC. Development of stevioside Pluronic-F-68 copolymer based PLA-nanoparticles as an antidiabetic nanomedicine. Colloids Surf B Biointerfaces 2012; 101:510-6. [PMID: 23022553 DOI: 10.1016/j.colsurfb.2012.07.005] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2012] [Revised: 06/06/2012] [Accepted: 07/10/2012] [Indexed: 10/28/2022]
Abstract
Stevioside (FDA approved nontoxic natural non-caloric sweetener) has been reported to have very good antidiabetic potential but its use as therapeutic drug is restricted in human due to its deprived intestinal absorption and poor bioavailability. We have nano-bioconjugated this molecule on biodegradable Pluronic-F-68 copolymer based PLA nanoparticles by nanoprecipitation method (spherical, size range 110-130 nm) to overcome deprived intestinal absorption and to enhance the bioavailability. The drug loading calculated by the standard calibrated HPLC was 16.32±4% (w/w). The in vitro release study showed the initial burst followed by the sustained release. The half release and complete release were observed on 25±4 h and 200±10 h respectively. This newly formulated nanostevioside showed very high potential to be used as antidiabetic nanomedicine for safe and effective use in vivo.
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Affiliation(s)
- Indu Barwal
- Biotechnology Division, Council of Scientific and Industrial Research, Institute of Himalayan Bioresource Technology (CSIR-IHBT), Palampur, HP, India
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Chen Z, Wei X, Li J, Di D. Preparative separation of Rebaudiana A from commercialized steviol glycosides by macroporous adsorption resins mixed bed. Sep Purif Technol 2012. [DOI: 10.1016/j.seppur.2012.01.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Kataev E, Khaybullin RN, Sharipova RR, Strobykina IY. Ent-kaurane diterpenoids and glycosides: Isolation, properties, and chemical transformations. ACTA ACUST UNITED AC 2011. [DOI: 10.1134/s2079978011010043] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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Misra H, Soni M, Silawat N, Mehta D, Mehta BK, Jain DC. Antidiabetic activity of medium-polar extract from the leaves of Stevia rebaudiana Bert. (Bertoni) on alloxan-induced diabetic rats. JOURNAL OF PHARMACY AND BIOALLIED SCIENCES 2011; 3:242-8. [PMID: 21687353 PMCID: PMC3103919 DOI: 10.4103/0975-7406.80779] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2010] [Revised: 09/15/2010] [Accepted: 11/01/2010] [Indexed: 12/04/2022] Open
Abstract
OBJECTIVE To investigate the medicative effects of medium-polar (benzene:acetone, 1:1, v/v) extract of leaves from Stevia rebaudiana (family Asteraceae) on alloxan-induced diabetic rats. MATERIALS AND METHODS Diabetes was induced in adult albino Wistar rats by intraperitoneal (i.p.) injection of alloxan (180 mg/kg). Medium-polar extract was administered orally at daily dose of 200 and 400 mg/kg body wt. basis for 10 days. The control group received normal saline (0.9%) for the same duration. Glibenclamide was used as positive control reference drug against Stevia extract. RESULTS Medium-polar leaf extract of S. rebaudiana (200 and 400 mg/kg) produced a delayed but significant (P < 0.01) decrease in the blood glucose level, without producing condition of hypoglycemia after treatment, together with lesser loss in the body weight as compared with standard positive control drug glibenclamide. CONCLUSIONS Treatment of diabetes with sulfonylurea drugs (glibenclamide) causes hypoglycemia followed by greater reduction in body weight, which are the most worrisome effects of these drugs. Stevia extract was found to antagonize the necrotic action of alloxan and thus had a re-vitalizing effect on β-cells of pancreas.
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Affiliation(s)
- Himanshu Misra
- School of Studies in Chemistry and Biochemistry, Vikram University, Ujjain – 456 010, Madhya Pradesh, India
- Green Technology, Ipca Laboratories Limited, Ratlam – 457 002, Madhya Pradesh, India
| | - Manish Soni
- Department of Pharmacognosy, Mandsaur Institute of Pharmacy, Mandsaur – 458 001, Madhya Pradesh, India
| | - Narendra Silawat
- Department of Pharmacology, B. R. Nahata College of Pharmacy, Mandsaur – 458 001, Madhya Pradesh, India
| | - Darshana Mehta
- School of Studies in Chemistry and Biochemistry, Vikram University, Ujjain – 456 010, Madhya Pradesh, India
| | - B. K. Mehta
- School of Studies in Chemistry and Biochemistry, Vikram University, Ujjain – 456 010, Madhya Pradesh, India
| | - D. C. Jain
- Green Technology, Ipca Laboratories Limited, Ratlam – 457 002, Madhya Pradesh, India
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Scientific Opinion on the safety of steviol glycosides for the proposed uses as a food additive. EFSA J 2010. [DOI: 10.2903/j.efsa.2010.1537] [Citation(s) in RCA: 98] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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Abudula R, Matchkov VV, Jeppesen PB, Nilsson H, Aalkjaer C, Hermansen K. Rebaudioside A directly stimulates insulin secretion from pancreatic beta cells: a glucose-dependent action via inhibition of ATP-sensitive K-channels. Diabetes Obes Metab 2008; 10:1074-85. [PMID: 18435771 DOI: 10.1111/j.1463-1326.2008.00864.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Recently, we showed that rebaudioside A potently stimulates the insulin secretion from isolated mouse islets in a dose-, glucose- and Ca(2+)-dependent manner. Little is known about the mechanisms underlying the insulinotropic action of rebaudioside A. The aim of this study was to define the signalling system by which, rebaudioside A acts. Isolated mouse islets were used in the cAMP[(125)I] scintillation proximity assay to measure total cAMP level, and in a luminometric method to measure intracellular ATP and ADP concentrations. Conventional and permeabilized whole-cell configuration of the patch-clamp technique was used to verify the effect of rebaudioside A on ATP-sensitive K(+)-channels from dispersed single beta cells from isolated mouse islets. Insulin was measured by radioimmunoassay from insulinoma MIN6 cells. In the presence of 16.7 mM glucose, the addition of the maximally effective concentration of rebaudioside A (10(-9) M) increased the ATP/ADP ratio significantly, while it did not change the intracellular cAMP level. Rebaudioside A (10(-9) M) and stevioside (10(-6) M) reduced the ATP-sensitive potassium channel (K(ATP)) conductance in a glucose-dependent manner. Moreover, rebaudioside A stimulated the insulin secretion from MIN6 cells in a dose- and glucose-dependent manner. In conclusion, the insulinotropic effect of rebaudioside A is mediated via inhibition of ATP-sensitive K(+)-channels and requires the presence of high glucose. The inhibition of ATP-sensitive K(+)-channels is probably induced by changes in the ATP/ADP ratio. The results indicate that rebaudioside A may offer a distinct therapeutic advantage over sulphonylureas because of less risk of causing hypoglycaemia.
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Affiliation(s)
- R Abudula
- Department of Endocrinology and Metabolism C, Aarhus University Hospital, Aarhus C, Denmark
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Remedi MS, Nichols CG. Chronic antidiabetic sulfonylureas in vivo: reversible effects on mouse pancreatic beta-cells. PLoS Med 2008; 5:e206. [PMID: 18959471 PMCID: PMC2573909 DOI: 10.1371/journal.pmed.0050206] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2008] [Accepted: 09/09/2008] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Pancreatic beta-cell ATP-sensitive potassium (K ATP) channels are critical links between nutrient metabolism and insulin secretion. In humans, reduced or absent beta-cell K ATP channel activity resulting from loss-of-function K ATP mutations induces insulin hypersecretion. Mice with reduced K ATP channel activity also demonstrate hyperinsulinism, but mice with complete loss of K ATP channels (K ATP knockout mice) show an unexpected insulin undersecretory phenotype. Therefore we have proposed an "inverse U" hypothesis to explain the response to enhanced excitability, in which excessive hyperexcitability drives beta-cells to insulin secretory failure without cell death. Many patients with type 2 diabetes treated with antidiabetic sulfonylureas (which inhibit K ATP activity and thereby enhance insulin secretion) show long-term insulin secretory failure, which we further suggest might reflect a similar progression. METHODS AND FINDINGS To test the above hypotheses, and to mechanistically investigate the consequences of prolonged hyperexcitability in vivo, we used a novel approach of implanting mice with slow-release sulfonylurea (glibenclamide) pellets, to chronically inhibit beta-cell K ATP channels. Glibenclamide-implanted wild-type mice became progressively and consistently diabetic, with significantly (p < 0.05) reduced insulin secretion in response to glucose. After 1 wk of treatment, these mice were as glucose intolerant as adult K ATP knockout mice, and reduction of secretory capacity in freshly isolated islets from implanted animals was as significant (p < 0.05) as those from K ATP knockout animals. However, secretory capacity was fully restored in islets from sulfonylurea-treated mice within hours of drug washout and in vivo within 1 mo after glibenclamide treatment was terminated. Pancreatic immunostaining showed normal islet size and alpha-/beta-cell distribution within the islet, and TUNEL staining showed no evidence of apoptosis. CONCLUSIONS These results demonstrate that chronic glibenclamide treatment in vivo causes loss of insulin secretory capacity due to beta-cell hyperexcitability, but also reveal rapid reversibility of this secretory failure, arguing against beta-cell apoptosis or other cell death induced by sulfonylureas. These in vivo studies may help to explain why patients with type 2 diabetes can show long-term secondary failure to secrete insulin in response to sulfonylureas, but experience restoration of insulin secretion after a drug resting period, without permanent damage to beta-cells. This finding suggests that novel treatment regimens may succeed in prolonging pharmacological therapies in susceptible individuals.
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Chen J, Jeppesen PB, Nordentoft I, Hermansen K. Stevioside improves pancreatic beta-cell function during glucotoxicity via regulation of acetyl-CoA carboxylase. Am J Physiol Endocrinol Metab 2007; 292:E1906-16. [PMID: 17341549 DOI: 10.1152/ajpendo.00356.2006] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Chronic hyperglycemia is detrimental to pancreatic beta-cells, causing impaired insulin secretion and beta-cell turnover. The characteristic secretory defects are increased basal insulin secretion (BIS) and a selective loss of glucose-stimulated insulin secretion (GSIS). Several recent studies support the view that the acetyl-CoA carboxylase (ACC) plays a pivotal role for GSIS. We have shown that stevioside (SVS) enhances insulin secretion and ACC gene expression. Whether glucotoxicity influences ACC and whether this action can be counteracted by SVS are not known. To investigate this, we exposed isolated mouse islets as well as clonal INS-1E beta-cells for 48 h to 27 or 16.7 mM glucose, respectively. We found that 48-h exposure to high glucose impairs GSIS from mouse islets and INS-1E cells, an effect that is partly counteracted by SVS. The ACC dephosphorylation inhibitor okadaic acid (OKA, 10(-8) M), and 5-aminoimidazole-4-carboxamide-1-beta-d-ribofuranoside (AICAR, 10(-4) M), an activator of 5'-AMP protein kinase that phosphorylates ACC, eliminated the beneficial effect of SVS. 5-Tetrade-cyloxy-2-furancarboxylic acid (TOFA), the specific ACC inhibitor, blocked the effect of SVS as well. During glucotoxity, ACC gene expression, ACC protein, and phosphorylated ACC protein were increased in INS-1E beta-cells. SVS pretreatment further increased ACC gene expression with strikingly elevated ACC activity and increased glucose uptake accompanied by enhanced GSIS. Our studies show that glucose is a potent stimulator of ACC and that SVS to some extent counteracts glucotoxicity via increased ACC activity. SVS possesses the potential to alleviate negative effects of glucotoxicity in beta-cells via a unique mechanism of action.
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Affiliation(s)
- Jianguo Chen
- Department of Endocrinology and Metabolism, C. Aarhus Sygehus THG, Aarhus University Hospital, Tage-Hansens Gade 2, DK-8000 Aarhus C, Denmark.
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Chen J, Jeppesen PB, Nordentoft I, Hermansen K. Stevioside Counteracts Beta-Cell Lipotoxicity without Affecting Acetyl CoA Carboxylase. Rev Diabet Stud 2007; 3:178-88. [PMID: 17487342 PMCID: PMC1828288 DOI: 10.1900/rds.2006.3.178] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Chronic exposure to high levels of free fatty acids impairs beta-cell function (lipotoxicity). Then basal insulin secretion (BIS) is increased and glucose-stimulated insulin secretion (GSIS) is inhibited. Acetyl CoA carboxylase (ACC) acts as the sensor for insulin secretion in pancreatic beta-cells in response to glucose and other nutrients. Stevioside (SVS), a diterpene glycoside, has recently been shown to prevent glucotoxic effect by regulating ACC activity. The aim of this study was to investigate whether SVS can alleviate impaired beta-cell function by regulating ACC activity. We exposed isolated rat islets and the clonal beta-cell line, INS-1E, to palmitate concentrations of 1.0 or 0.6 mM, respectively, for a period of 24 h to 120 h. The results showed that lipotoxicity occurred in rat islets after 72 h exposure to 1.0 mM palmitate. The lipotoxicity was counteracted by 10(-6) M SVS (n = 8, p < 0.001). Similar results were obtained in INS-1E cells. Neither SVS nor palmitate had any effect on the gene expression of ACC, insulin 2, and glucose transporter 2 in INS-1E cells. In contrast, palmitate significantly increased the gene expression of carnitine palmitoyl transporter 1 (n = 6, p = 0.003). However, the addition of SVS to palmitate did not counteract this effect (n = 6, p = 1.0). During lipotoxicity, SVS did not alter levels of ACC protein, phosphorylated-ACC, ACC activity or glucose uptake. Our results showed that SVS counteracts the impaired insulin secretion during lipotoxicity in rat islets as well as in INS-1E cells without affecting ACC activity.
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Affiliation(s)
- Jianguo Chen
- Address correspondence to: Jianguo Chen, e-mail:
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