Type 2 diabetes mellitus—Its global prevalence and therapeutic strategies

Design, synthesis, α-amylase and glucose diffusion inhibition, and molecular docking studies of new indenopyrazolones bearing benzothiazole derivatives

An eco-friendly facile synthesis of a series of twenty 1-(4/6-substitutedbenzo[d]thiazol-2-yl)-3-(phenyl/substitutedphenyl)indeno[1,2-c]pyrazol-4(1H)-ones 7a-t was achieved by the reaction of 2-(benzoyl/substitutedbenzoyl)-(1H)-indene-1,3(2H)-dione 3a-t and 2-hydrazinyl-4/6-substitutedbenzo[d]thiazole 6a-t in presence of freshly dried ethanol and glacial acetic acid under reflux conditions in good yields. The newly synthesized derivatives were well characterized using different physical and spectral techniques (FTIR, 1H NMR & 13C NMR, and HRMS). All the compounds were subjected to assess their in vitro α-amylase and glucose diffusion inhibitory activity. Amongst them, the compounds 7i and 7l showed better α-amylase inhibitory activity demonstrating IC50 values of 92.99±1.94 µg/mL and 95.41±3.92 µg/mL, respectively in comparison to the standard drug acarbose (IC50 value of 103.60±2.15 µg/mL). The derivatives 7d and 7k exhibited good glucose diffusion inhibition with values of 2.25±1.16 µg/mL and 2.63±1.45 µg/mL, respectively with standard reference acarbose (2.76±0.55 µg/mL). The observed α-amylase inhibitory activity findings were corroborated through molecular docking investigations, particularly for the highly active compounds 7i (binding energy -8.0 kcal/mol) and 7l (binding energy -8.2 kcal/mol) respectively, in comparison to acarbose with a value of binding energy -6.9 kcal/mol for α-amylase.

In vitro α-amylase and α-glucosidase inhibition study of dihydropyrimidinones synthesized via one-pot Biginelli reaction in the presence of a green catalyst

A green catalyst WELPSA-catalyzed three-component condensation (Biginelli) process involving an aldehyde, barbituric/thiobarbituric/1,3-dimethylbarbituric acid, and urea/thiourea/guanidine hydrochloride in a single pot in presence of a green solvent for the production of DHPM have been presented. The catalyst is reusable and this methodology is scalable. By using the in vitro experiments, the antidiabetic potentiality of synthesized compounds that inhibit α-amylase along with α-glucosidase efficiencies was assessed. All the synthesized compounds except for 4a and 4e, showed the most significant inhibition for α-amylase and α-glucosidase activities. Among the synthesized DHPM compounds, 4c and 4b exhibited significant inhibition profiles compared to the standard antidiabetic drug acarbose. Furthermore, synthesized substances' energy-minimized structures, 3D structures, and DFT calculations were performed using Gaussian 09 software, hybrid models, and MM2 force approaches. Strong hydrogen bonds with amino acid residues Arg-672, Arg-600, Trp-613, Asp-404, Asp-282, and Asp-616 indicate that an α-glucosidase-inhibitory peptide may have hypoglycemic efficacy confirmed by the molecular docking study of the synthesized DHPM.

Role of proprotein convertase subtilisin/kexin type 9 (PCSK9) in diabetic complications

Cardiovascular disease (CVD) complications have remained a major cause of death among patients with diabetes. Hence, there is a need for effective therapeutics against diabetes-induced CVD complications. Since its discovery, proprotein convertase subtilisin/kexin type 9 (PCSK9) has been reported to be involved in the pathology of various CVDs, with studies showing a positive association between plasma levels of PCSK9, hyperglycemia, and dyslipidemia. PCSK9 regulates lipid homeostasis by interacting with low-density lipoprotein receptors (LDLRs) present in hepatocytes and subsequently induces LDLR degradation via receptor-mediated endocytosis, thereby reducing LDL uptake from circulation. In addition, PCSK9 also induces pro-inflammatory cytokine expression and apoptotic cell death in diabetic-CVD. Furthermore, therapies designed to inhibit PCSK9 effectively reduces diabetic dyslipidemia with clinical studies reporting reduced cardiovascular events in patients with diabetes and no significant adverse effect on glycemic controls. In this review, we discuss the role of PCSK9 in the pathogenesis of diabetes-induced CVD and the potential mechanisms by which PCSK9 inhibition reduces cardiovascular events in diabetic patients.

Investigation of the Potential Phlorotannins and Mechanism of Six Brown Algae in Treating Type II Diabetes Mellitus Based on Biological Activity, UPLC-QE-MS/MS, and Network Pharmacology

Type 2 diabetes mellitus (T2DM) has developed into an important health concern worldwide. The discovery of phlorotannins and their efficacy in the treatment of T2DM has become a hotspot for research in various fields. In this study, the potential phlorotannins and mechanism of six brown algae against T2DM were in-depth investigated using biological activity assays, LC-MS, and network pharmacology. First, the ethyl acetate fraction (EA frac.) showed high polyphenolic content and possessed significantly antioxidant and enzyme inhibitory abilities. Further, a total of fifty-nine peaks were obtained from six EA fracs. via UPLC-QE-MS/MS analysis, and fifteen of them were identified as phlorotannins and their isomers or derivatives. In detail, the chemical structures of six phlorotannins were inferred as dibenzodioxine-1,3,6,8-tetraol, bifuhalol, dioxinodehydroeckol, eckol, fucofurodiphlorethol, and fucotriphlorethol; three phlorotannin isomers were deduced to be fucophlorethol, trifucol, triphlorethol A, or triphlorethol B; and the phlorotannin derivative of m/z 263 was determined to be dibenzodioxine-1,2,3,6,8-pentanol or dibenzodioxine-1,2,4,5,7-pentanol. Moreover, 43 T2DM-related targets acted on by these chemicals were identified, and the function of phlorotannin to prevent and treat T2DM was elucidated in a holistic way based on the established compound-target-disease network, and GO function and KEGG pathway enrichment analysis.

The mechanism of in vitro non-enzymatic glycosylation inhibition by Tartary buckwheat's rutin and quercetin

Tartary buckwheat is rich in rutin, quercetin, and other flavonoids, which exert prominent effects by inhibiting non-enzymatic glycosylation. In this study, an in vitro non-enzymatic glycosylation model was established, and the inhibitory effects of rutin and quercetin on the early, middle, and late products of non-enzymatic glycosylation were determined. Furthermore, their effects on the formation of advanced glycation end products (AGEs) and on protein functional groups and secondary structure were analyzed. These findings provided a theoretical basis for further investigation of the mechanism via which Tartary buckwheat's rutin and quercetin inhibited non-enzymatic glycosylation. The results showed that rutin and quercetin inhibited the formation of fructosamine, dicarbonyl compounds, and fluorescent AGE in a concentration-dependent manner. Rutin and quercetin exhibited antioxidant activity and could reduce the formation of protein oxidation products. The highest clearance rates for DPPH and ABTS⁺ were 62.74 % and 71.14 %, respectively.

Synthesis of Novel 2,3-Dihydro-1,5-Benzothiazepines as α-Glucosidase Inhibitors: In Vitro, In Vivo, Kinetic, SAR, Molecular Docking, and QSAR Studies

In the present study, a series of 2,3-dihydro-1,5-benzothiazepine derivatives 1B-14B has been synthesized sand characterized by various spectroscopic techniques. The enzyme inhibitory activities of the target analogues were assessed using in vitro and in vivo mechanism-based assays. The tested compounds 1B-14B exhibited in vitro inhibitory potential against α-glucosidase with IC50 = 2.62 ± 0.16 to 10.11 ± 0.32 μM as compared to the standard drug acarbose (IC50 = 37.38 ± 1.37 μM). Kinetic studies of the most active derivatives 2B and 3B illustrated competitive inhibitions. Based on the α-glucosidase inhibitory effect, the compounds 2B, 3B, 6B, 7B, 12B, 13B, and 14B were chosen in vivo for further evaluation of antidiabetic activity in streptozotocin-induced diabetic Wistar rats. All these evaluated compounds demonstrated significant antidiabetic activity and were found to be nontoxic in nature. Moreover, the molecular docking study was performed to elucidate the binding interactions of most active analogues with the various sites of the α-glucosidase enzyme (PDB ID 3AJ7). Additionally, quantitative structure-activity relationship (QSAR) studies were performed based on the α-glucosidase inhibitory assay. The value of correlation coefficient (r) 0.9553 shows that there was a good correlation between the 1B-14B structures and selected properties. There is a correlation between the experimental and theoretical results. Thus, these novel compounds could serve as potential candidates to become leads for the development of new drugs provoking an anti-hyperglycemic effect.

Effectiveness of theory-based Multimedia Messaging Service (MMS) on exercise benefits and barriers among patients with type 2 diabetes

The current study aimed to examine the effectiveness of multimedia messaging service (MMS) education on exercise benefits and barriers in patients with type 2 diabetes. A quasi-experimental, pretest-post-test design recruited 98 patients with type 2 diabetes. The intervention group received MMS education to improve perceived exercise benefits and decrease exercise barriers over two months, and the control group received routine care. All patients completed a survey at three time points (baseline, 4 and 8 weeks post-intervention). The results showed that there was an improvement in both perceived life enhancement and physical performance domains in the intervention group. The exercise context barriers decreased after the first follow-up but increased during the second follow-up in the intervention group. Cohen's d values indicated a medium effect size in life enhancement (0.502) and physical performance (0.525) subscales. A small effect size was found in psychological outlook (0.196) and exercise context (0.132) subscales. However, there was no significant effect of the intervention in time expenditure (-0.244) and physical exertion (-0.119) subscales. In conclusion, theoretically based MMS health education targeting perceived exercise benefits and barriers was feasible and cost-effective in changing patients with diabetes' perceptions and intended behaviors about regular physical activity.

Identifying Behavioural Determinants to Uptake and Adherence to a Whey Protein Supplement for the Management of Type 2 Diabetes: A Qualitative Interview Study

Interventions targeting diet and physical activity have demonstrated to be effective for improving glycaemic control in adults with type 2 diabetes. However, initiating and sustaining these changes remains a challenge. Ingestion of whey protein has shown to be effective for improving glycaemic control by increasing insulin and incretin secretion, and influencing appetite regulation; however, little is known about what influences uptake and adherence. We conducted a qualitative interview study to explore behavioural determinants of uptake and adherence to a commercially made whey protein supplementation. In total, 16/18 adults with type 2 diabetes who participated in an RCT took part in a semi-structured interview. Seven themes were generated from the data following thematic analyses. The most frequently reported determinant of uptake was the expectation that the supplement would improve health status (e.g., type 2 diabetes management), as a consequence of appetite suppression and weight loss. Determinants of adherence included palatability; the belief that the supplement was an appetite suppressant; and receiving positive reinforcement on the effects of the supplement. Frequency of consumption led to reduced adherence with some participants. Findings support that the whey protein supplement is a viable management option for adults with type 2 diabetes; however, uptake will be driven by conveying information on the positive effects of the supplement on appetite suppression and glycaemic control. Adherence will be determined by palatability, behavioural prompting, and positive reinforcement.

Investigation of anti-diabetic potential and molecular simulation studies of dihydropyrimidinone derivatives

In an attempt to find new targets for α-amylase and α-glucosidase for the treatment of type 2 diabetes mellitus, the present study aims in determining the anti-diabetic potential of synthesized dihydropyrimidinone derivatives. The in vitro α-glucosidase and α-amylase inhibitory activity was performed and the molecular docking analysis of the ligand in the active binding site of target protein was determined. The results revealed significant percent inhibition of α-glucosidase by the compound 6-benzyl-4-(4-hydroxyphenyl)-3,4,6,7-tetrahydro-1H-pyrrolo[3,4-d]pyrimidine-2,5-dione (compound A). The active compound showed 81.99% inhibition when compared to standard ascorbic acid having percent inhibition 81.18%. The IC₅₀ of active compound (A) showed to be 1.02 µg/ml. The molecular docking analysis revealed that the ligand bound to the active binding site of protein with the lowest binding energy of -7.9 kcal/mol that was also significantly similar to standard having -7.8 kcal/mol binding energy. The molecular dynamic simulation studies also revealed stable binding of ligand in the active binding site of protein with low RMSD of 1.7 Å similar to the protein RMSD 1.6Å In conclusion, the study revealed a potential new target against α-glucosidase to treat type 2 diabetes mellitus.

The Effects of Colocasia esculenta Leaf Extract in Inhibition of Erythrocyte Aldose Reductase Activity and Increase of Haemoglobin in Experimental Rats

Diabetes Mellitus (DM) has reached a number of 382 million in 2013 and expected to rise to 592 million by 2035. Chronic diabetes can lead to impaired formation of erythropoietin in haemoglobin production and may cause anemia. Inhibition of aldose reductase is a key point of diabetes treatment and prevention of complications in diabetes. Colocasia esculenta (CE) leaf is one of Indonesian vegetables which has inhibition effect on aldose reductase activity. This research was a true experimental study with post-test only group design. 21 male Sprague dawley rats were divided into: K (control group), P1 (extract CE 200 mg/KgBW) and P2 (extract CE 400 mg/KgBW). Rats were induced to become obese with High Fat Sucrose Diet (HFSD) for 4 wk then extract CE were given for 3 wk. The data were analyzed with independent t-test. CE have a significant effect to increase haemoglobin but have no significant inhibition effect to erythrocyte aldose reductase activity. The results of this research found that the mean haemoglobin of control group was 13.14±1.55, treatment group 1 (P1) was 15.22±0.59, and treatment group 2 (P2) was 15.77±0.71. There was significant increase in haemoglobin (p<0.05). The mean of aldose reductase activity of treatment group was lower than control group. However, there was no significant difference found (p>0.05) between the groups. 200 mg/kgBW and 400 mg/kgBW dose of CE could increase haemoglobin and decrease the mean of aldose reductase activity.

The effect of dried Ziziphus vulgaris on glycemic control, lipid profile, Apo-proteins and hs-CRP in patients with type 2 diabetes mellitus: A randomized controlled clinical trial

We aimed to evaluate the effect of dried Ziziphus vulgaris [Z. vulgaris] consumption on liver enzymes, blood pressure, inflammatory status, glycemic control, and lipid concentrations in type 2 diabetes patients. Seventy-six diabetic participants (aged 20-65 years) randomly assigned to intervention (n = 38) and placebo (n = 38) groups. The intervention group received 30 g/day dried Z. vulgaris for 12 weeks. At the end of the study, there was a significant reduction in the percentage change of weight, body mass index [BMI], insulin, homeostasis model assessment-insulin resistance [HOMA-IR], Apoprotein B100 [ApoB100], and high-sensitive c-reactive protein [hs-CRP] in the intervention group compared to the controls. Also, increased values of quantitative insulin check index [QUICKI] and Apoprotein A-I [ApoA-I] in Z. vulgaris group compared to the controls were observed. In conclusion, consumption of dried Z. vulgaris fruit could have beneficial effects on improving the glycemic control and reducing the cardiovascular risk factors in the diabetic patients. PRACTICAL APPLICATIONS: In the present study we found that consumption of 30 g/day dried Z. vulgaris fruit in patients with type 2 diabetes for 12 weeks has beneficial anti-inflammatory, anti-hyperglycemic, and anti-hyperlipidemic effects on type 2 diabetes mellitus [T2DM] patients compared to the control group. Thus, it seems reasonable to design a large-scale clinical trial to determine the potential adverse effects of higher doses of this fruit and identify the therapeutic doses for the complementary treatment in T2DM medication. The medication with this popular fruit as an ingredient could be easily accepted by diabetic patients and may reduce the dependency and dosage of some of the routine diabetes medications which often have some adverse side effects.

A Systematic Review on Synthetic Drugs and Phytopharmaceuticals Used to Manage Diabetes

BACKGROUND

Diabetes is a multifactorial disease and a major cause for many microvascular and macrovascular complications. The disease will ultimately lead to high rate mortality if it is not managed properly. Treatment of diabetes without any side effects has always remained a major challenge for health care practitioners.

INTRODUCTION

The current review discusses the various conventional drugs, herbal drugs, combination therapy and the use of nutraceuticals for the effective management of diabetes mellitus. The biotechnological aspects of various antidiabetic drugs are also discussed.

METHODS

Structured search of bibliographic databases for previously published peer-reviewed research papers was explored and data was sorted in terms of various approaches that are used for the treatment of diabetes.

RESULTS

More than 170 papers including both research and review articles, were included in this review in order to produce a comprehensive and easily understandable article. A series of herbal and synthetic drugs have been discussed along with their current status of treatment in terms of dose, mechanism of action and possible side effects. The article also focuses on combination therapies containing synthetic as well as herbal drugs to treat the disease. The role of pre and probiotics in the management of diabetes is also highlighted.

CONCLUSION

Oral antihyperglycemics which are used to treat diabetes can cause many adverse effects and if given in combination, can lead to drug-drug interactions. The combination of various phytochemicals with synthetic drugs can overcome the challenge faced by the synthetic drug treatment. Herbal and nutraceuticals therapy and the use of probiotics and prebiotics are a more holistic therapy due to their natural origin and traditional use.

In vitro and in vivo Antidiabetic Properties of Phenolic Antioxidants From Sedum adenotrichum

Natural products serve as the mainstay of human life, and today, almost half of the drugs in clinical practice are the natural origin. Keeping in view the importance of medicinal plants and natural products, Sedum adenotrichum also known as Rosularia adenotrichum was selected for the present study. The crude extract of S. adenotrichum whole plant was obtained through a rotary evaporator. The extract was analyzed for a polyphenolic profile using high-performance liquid chromatography with a diode-array detector. The extract was subjected to detail in vivo antidiabetic study. In this study, body weight, blood glucose level, glycated hemoglobin, lipid profile, liver function tests, and renal function tests were performed in animal models. The extract was tested for in vitro α-glucosidase inhibition activity. Results of high-performance liquid chromatography with a diode-array detector chromatogram revealed a total of 22 polyphenolic compounds. No major change in body weight was noted in experimental animals. Alloxan induction led to a significant elevation in plasma glucose level. A significant decline was noted in blood glucose and glycated hemoglobin concentration in rats treated with the extract as well as with glibenclamide. Renal/liver function tests, lipid profile, alkaline phosphatase, and serum cholesterol were normalized by the extract-treated rats. The α-glucosidase inhibitory activity at 62.5 and 1,000 μg/ml was noted to be 63.97 and 80.80, respectively, both approaching to standard. The results reveal that the extract was rich in important phenolic compounds. In the antidiabetic potentials of the crude extract, there might be involved several pancreatic and extra-pancreatic mechanisms acting synergistically to induce the potent antidiabetic effect.

Fabrication of Second Generation Smarter PLGA Based Nanocrystal Carriers for Improvement of Drug Delivery and Therapeutic Efficacy of Gliclazide in Type-2 Diabetes Rat Model

Drug delivery and therapeutic challenges of gliclazide, a BCS class II drug used in type 2 diabetes mellitus (T2DM) can be overcome by exploring smarter carriers of second-generation nanocrystals (SGNCs). A combined method of emulsion diffusion, high-pressure homogenization and solvent evaporation method were employed in the preparation of gliclazide loaded poly (D, L-lactide-co-glycolide) (PLGA) SGNCs. Taguchi experimental design was adopted in fabrication of Gliclazide SGNc using Gliclazide -PLGA ratio at 1:0.5, 1:0.75, 1:1 with stabilizer (Poloxamer-188, PEG 4000, HPMC E15 at 0.5, 0.75, 1% w/v). The formulated gliclazide of SGNCs were investigated for physicochemical properties, in vitro drug release, and in vivo performance studies using type-2 diabetes rat model. The formulation (SGNCF1) with Drug: PLGA 1: 0.5 ratio with 0.5% w/v Poloxamer-188 produced optimized gliclazide SGNCs. SGNCF1 showed spherical shape, small particle size (106.3 ± 2.69 nm), good zeta potential (−18.2 ± 1.30 mV), small PDI (0.222 ± 0.104) and high entrapment efficiency (86.27 ± 0.222%). The solubility, dissolution rate and bioavailability of gliclazide SGNCs were significantly improved compared to pure gliclazide. The findings emphasize gliclazide SGNCs produce faster release initially, followed by delayed release with improved bioavailability, facilitate efficient delivery of gliclazide in T2DM with better therapeutic effect.

Moringa oleifera and glycemic control: A review of current evidence and possible mechanisms

Maintaining glycemic control in diabetes and prediabetes is necessary to prevent many health complications and mortality. Although different hypoglycemic drugs are used for this purpose, there is still a growing interest in the use of medicinal plants due to their low price, easy availability, and fewer or no side effects. Moringa (Moringa oleifera Lam.) is a medicinal plant that has been traditionally used in the management of diabetes. This review aims to present the existing literature published until February 2019 on the role of moringa leaves in glycemia and their physiological mechanisms. In the conducted studies, moringa leaves have shown to reduce glycemia, without causing any adverse effects. The proposed mechanisms for reducing glycemia include inhibition of α-amylase and α-glucosidase activities, increased glucose uptake in the muscles and liver, inhibition of glucose uptake from the intestine, decreased gluconeogenesis in the liver, and increased insulin secretion and sensitivity. However, these studies are limited in numbers and mostly conducted in animals, in vitro and in vivo. Therefore, long-term human studies are required to determine the hypoglycemic effect of moringa leaves, their physiological mechanisms, active ingredients, and safety. Overall, this review provides evidence that moringa leaves have the possibility to be used as a glycemic control agent in diabetes and prediabetes.

Screening and Isolating Major Aldose Reductase Inhibitors from the Seeds of Evening Primrose (Oenothera biennis)

Aldose reductase (AR) is a drug target for therapies to treat complications caused by diabetes mellitus, and the development of effective AR inhibitors (ARIs) of natural origin is considered to be an attractive option for reducing these complications. In this research, the rat lens AR (RLAR) inhibitory activity of evening primrose (Oenothera biennis) seeds was investigated for the first time. In our results, the 50% (v/v) methanol extract of evening primrose seeds exhibits excellent RLAR inhibitory activity (IC50 value of 7.53 μg/mL). Moreover, after enrichment of its bioactive components, the ARIs are more likely to be present in the ethyl acetate fraction of 50% (v/v) methanol extract (EME) of evening primrose seeds, which exhibits superior RLAR inhibitory activity (IC50 value of 3.08 µg/mL). Finally, gallic acid (1), procyanidin B3 (2), catechin (3), and methyl gallate (4) were identified as the major ARIs from the EME by affinity-based ultrafiltration-high-performance liquid chromatography and were isolated by high speed countercurrent chromatography, with gallic acid (11.46 µmol/L) and catechin (14.78 µmol/L) being the more potent inhibitors of the four ARIs identified. The results demonstrated that evening primrose seeds may be a potent ingredient of ARIs.

The impact of exposure of diabetic rats to 900 MHz electromagnetic radiation emitted from mobile phone antenna on hepatic oxidative stress

The excessive exposure of patients with type 2 diabetes mellitus (T2DM) to electromagnetic radiation (EMR) from mobile phones or their base stations antenna may influence oxidative stress and development of diabetic complications. Here, we investigated the effects of exposing type 2 diabetic rats to EMR of 900 MHz emitted from GSM mobile phone antenna for 24 hours/day over a period of 28 days on hyperglycemia and hepatic oxidative stress. Male Sprague-Dawley rats were divided into 4 groups (12 rats/group): control rats, normal rats exposed to EMR, T2DM rats generated by nicotinamide/streptozotocin administration, and T2DM rats exposed to EMR. Our results showed that the exposure of T2DM rats to EMR nonsignificantly reduced the hyperglycemia and hyperinsulinemia compared to unexposed T2DM rats. The exposure of T2DM rats to EMR for 28 days increased the hepatic levels of MDA and Nrf-2 as well as the activities of superoxide dismutase (SOD) and catalase but decreased phosphorylated Akt-2 (pAkt-2) as compared to unexposed T2DM rats. Therefore, the decrease in the hepatic pAkt-2 in T2DM rats after the exposure to EMR may result in elevated level of hepatic MDA, even though the level of Nrf-2 and the activities of SOD and catalase were increased. Abbreviations: BGL: blood glucose level; EMR: electromagnetic radiation; GSM: global system for mobile communication; H2O2: hydrogen peroxide; LSD: least significance difference; MDA:malondialdehyde; Nrf-2: nuclear factor erythroid 2- related factor 2; PI3K: phosphoinositide-3-kinase; pAkt-2: phosphorylated Akt-2; Akt-2: protein kinase; ROS: reactive oxygen species; SEM: standard error of the mean; STZ: streptozotocin; SOD: superoxide dismutase ; O2-: superoxide radical; CT: threshold cycle; T2DM: type 2 diabetes mellitus.

2,4-Thiazolidinediones as PTP 1B Inhibitors: A Mini Review (2012-2018)

2,4-thiazolidinedione (TZD) scaffold is a synthetic versatile scaffold explored by medicinal chemists for the discovery of novel molecules for the target-specific approach to treat or manage number of deadly ailments. PTP 1B is the negative regulator of insulin signaling cascade, and its diminished activity results in abolishment of insulin resistance associated with T2DM. The present review focused on the seven years journey (2012-2018) of TZDs as PTP 1B inhibitors with the insight into the amendments in the structural framework of TZD scaffold in order to optimize/design potential PTP 1B inhibitors. We have investigated the synthesized molecules based on TZD scaffold with potential activity profile against PTP 1B. Based on the SAR studies, the combined essential pharmacophoric features of selective and potent TZDs have been mapped and presented herewith for further design and synthesis of novel inhibitors of PTP 1B. Compound 46 bearing TZD scaffold with N-methyl benzoic acid and 5-(3-methoxy-4-phenethoxy) benzylidene exhibited the most potent activity (IC50 1.1 µM). Imidazolidine-2,4-dione, isosteric analogue of TZD, substituted with 1-(2,4-dichlorobenzyl)-5-(3-(2,4- dichlorobenzyloxy)benzylidene) (Compound 15) also endowed with very good PTP inhibitory activity profile (IC50 0.57 µM). It is noteworthy that Z-configuration is essential in structural framework around the double bond of arylidene for the designing of bi-dentate ligands with optimum activity.

Biochemical and molecular study on interleukin-1β gene expression and relation of single nucleotide polymorphism in promoter region with Type 2 diabetes mellitus

Interleukin-1β (IL-1β) assumes a centric role in the regulation of immune and inflammatory responses and thus has been recognized in immune mediated diseases like type 2 diabetes mellitus (T2DM). We aimed to investigate expressed level of IL-1β and its relation with IL-1β -511T>C polymorphism in T2DM patients. This study enrolled 80 subjects (50 patients with T2DM and 30 healthy control subjects). Laboratory investigations included fasting (FBG) and 2 h postprandial blood sugar (2 h PBG), HBA1c, lipid profile, and renal function tests. Genotyping of IL-1β -511T>C (rs16944) SNP assay by real-time PCR and relative quantitation of IL-1β gene expression transcript by real-time PCR.

RESULTS

T2DM patients had significantly higher FBG and 2 h PBG, HBA1c, LDLc, TC, TG, systolic, and diastolic BP while lower HDLc compared with control group. IL 1- β -511 T>C, CC genotype and C allele were significantly associated with risk of T2DM with odds ratio (OR) 4.73, 95%CI (1.21-18.39) and OR 2.27, 95%CI (1.72-4.40), respectively. Moreover, diabetic patients had significantly higher IL 1- β gene transcript compared with control group (P < 0.001). CC genotype of IL 1- β -511 T > C had the highest significant level of IL 1- β gene transcript demonstrated compared with C/T and T/T genotypes (P < 0.001) in patients.

CONCLUSION

C allele of IL-1 β -511 T >C could be considered risk factor contributor to T2DM and excess level of IL-1 β transcript may disclose to some degree the inflammatory role of cytokines in T2DM.

Epidemiology of and Risk Factors for Type 2 Diabetes in Egypt

BACKGROUND

Diabetes is a fast-growing health problem in Egypt with a significant impact on morbidity, mortality, and health care resources. Currently, the prevalence of type 2 diabetes (T2D) in Egypt is around 15.6% of all adults aged 20 to 79.

OBJECTIVE

To describe the epidemiology, principal causes, associated risk factors, cultural aspects, and challenges that may contribute to the rapid rise in T2D in Egypt.

METHODS

Review of papers in PubMed and relevant gray literature.

FINDINGS

The International Diabetes Federation (IDF) has identified Egypt as the ninth leading country in the world for the number of patients with T2D. The prevalence of T2D in Egypt was almost tripled over the last 2 decades. This sharp rise could be attributed to either an increased pattern of the traditional risk factors for T2D such as obesity and physical inactivity and change in eating pattern or other risk factors unique to Egypt. These include increased exposure to environmental risk factors like pesticides and increased prevalence of chronic hepatitis C.

CONCLUSIONS

Prevention, early identification, and effective intervention are integral components of effective T2D care in Egypt. These strategies may reduce the expanding economic burden associated with T2D care.

Novel quinazolinone-based 2,4-thiazolidinedione-3-acetic acid derivatives as potent aldose reductase inhibitors

Aim: Targeting aldose reductase enzyme with 2,4-thiazolidinedione-3-acetic acid derivatives having a bulky hydrophobic 3-arylquinazolinone residue. Materials & methods: All the target compounds were structurally characterized by different spectroscopic methods and microanalysis, their aldose reductase inhibitory activities were evaluated, and binding modes were studied by molecular modeling. Results: All the synthesized compounds proved to inhibit the target enzyme potently, exhibiting IC50 values in the nanomolar/low nanomolar range. Compound 5i (IC50 = 2.56 nM), the most active of the whole series, turned out to be almost 70-fold more active than the only marketed aldose reductase inhibitor epalrestat. Conclusion: This work represents a promising matrix for developing new potential therapeutic candidates for prevention of diabetic complications through targeting aldose reductase enzyme.

[Formula: see text]

Investigation of the antioxidant and aldose reductase inhibitory activities of extracts from Peruvian tea plant infusions

In the present study, the antioxidant and aldose reductase inhibitory activities of 24 Peruvian infusion tea plants were investigated by 2,2'-diphenyl-1-picrylhydrazyl (DPPH), 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), and aldose reductase assays. Phoradendron sp. showed the highest inhibition of aldose reductase (IC₅₀, 1.09±0.06μg/mL) and considerable antioxidant (IC₅₀ of DPPH, 58.36±1.65μg/mL; IC₅₀ of ABTS, 9.91±0.43μg/mL) effects. In order to identify the antioxidants and aldose reductase inhibitors of Phoradendron sp., DPPH-high performance liquid chromatography (HPLC) and ultrafiltration-HPLC assays were performed. Chlorogenic acid, 3,5-di-O-caffeoylquinic acid, and 1,3,5-tri-O-caffeoylquinic acid were identified as the antioxidants and aldose reductase inhibitors; apigenin was identified as the antioxidant. Finally, Phoradendron sp. and its aldose reductase inhibitors also showed a dose-dependent anti-inflammatory effect without cellular toxicity. These results suggested that Phoradendron sp. can be a potent functional food ingredient as an antioxidant, aldose reductase inhibitor and anti-inflammatory agent.

Clinical and financial outcomes of switching insulin glargine to insulin detemir in a veteran population with type 2 diabetes

Background

Although glargine and detemir are both FDA-approved in the U.S. as long-acting insulin analogues, inherent differences in the insulins may lead to varying outcomes. This study examined changes in clinical measures and associated costs for veterans with type 2 diabetes on insulin therapy converted from insulin glargine to insulin detemir.

Methods

A retrospective before-and-after comparison study was performed at a single-site medical center located in the southwestern U.S., comprising 133 Veterans diagnosed with type 2 diabetes receiving insulin therapy with glargine and converted to insulin detemir using a 1:1 unit dosage ratio. Patients’ A1c, weight, body mass index, total daily dose, and estimated monthly insulin costs during and after conversion were compared employing Wilcoxon signed-rank tests. These measures were similarly assessed in patients at A1c goal (<7 %) prior to conversion.

Results

When switched from insulin glargine to insulin detemir, an increase in A1c (median of 7.7 % to 8.3 %, p < 0.01) and total daily dose (TDD: 40 to 46 units/day, p < 0.01) resulted. Monthly insulin costs decreased 19 % ($47 to $38, p < 0.01), or roughly a one-year savings of $110 per patient. An increase in A1c was similarly observed for patients at-goal prior to conversion but remained at-goal post-conversion (6.5 % to 6.7 %, p = 0.02).

Conclusion

The increase in A1c and TDD following conversion from insulin glargine to insulin detemir suggests that glargine requires a smaller amount of units to reach the same glycemic-lowering ability compared to detemir. Despite the observed insulin cost savings associated with detemir, future studies should also determine overall costs (including indirect) and benefits associated with switching from glargine to detemir among Veteran with Type 2 diabetes.

Therapeutic hypoglycemic potential of Pentapetes phoenicea L. in experimentally induced hyperglycemic rats

Diabetes mellitus is a metabolic disorder of endocrine system. This dreadful disease is found all over the world and is becoming a serious threat to the mankind health. Alternative to synthetic agents, plants provide a potential source of hypoglycemic drugs. The aim of the present study was to evaluate the hypoglycemic effect of 70% alcoholic extract of Pentapetesphoenicea (PPE) on blood glucose level in glucose loaded, normal and experimentally induced diabetic rats. Based on the acute toxicity test, two variable doses (250, 500 mg kg(-1) b.wt.) of hydro-alcoholic extract of P. phoenicea leaves were compared with glibenclamide for the influence on fasting blood glucose in glucose loaded, normoglycemic and streptozotocin (STZ) (55 mg kg(-1), i.p.) induced hyperglycemic rats. All the statistical comparisons were made by one-way analysis of variance (ANOVA) followed by Newman-Keuls Multiple Comparison Test using Graph Pad Prism 4.01 v for windows (Graph Pad Software, San Diego, CA, USA). The difference showing a p level of 0.05 or lower was considered to be statistically significant. The administration of PPE in two doses and glibenclamide (5 mg kg(-1)) to STZ induced hyperglycemic animals significantly lowered the blood glucose levels with 18.84% (p<0.01) for PPE 250 mg kg and 38.89% (p<0.001) for PPE 500 mg kg(-1) in a dose dependant manner. Considering all the results obtained, the study concludes that the hydro-alcoholic extract of P. phoenicea leaves produced promising decrease in blood glucose levels in STZ induced hyperglycemic rats which might be related to tannins, terpenoids, sterols and flavonoid contents.

Female sex, poverty and globalization as determinants of obesity among rural South African type 2 diabetics: a cross-sectional study

Background

Countries in Sub-Saharan Africa have recently been experiencing increases in the prevalence of obesity, type 2 diabetes mellitus (T2DM) and other non-communicable diseases in both urban and rural areas. Despite their growing influence on population health in the region, there is a paucity of epidemiological studies on the twin epidemic of obesity and T2DM, particularly in the rural communities in South Africa. We investigated the prevalence and the determinants of overall obesity among patients with T2DM in rural and semi-urban areas surrounding the town of Mthatha, South Africa.

Methods

This hospital-based cross-sectional study was conducted among patients with T2DM attending the outpatient department at Mthatha General Hospital, Eastern Cape Province, South Africa. Data were obtained from 327 participants using standardized questionnaires that included items on sex, age, level of education, type of residence, employment status, smoking status, physical activity, diet and alcohol intake. After taking measurements of height and weight, participants were defined as obese if their body mass index exceeded 30 kg/m². Univariate and multivariate logistic regression analyses were performed to identify the determinants of obesity in our sample population.

Results

We found that 60.2% of our sample population were defined as obese. In our univariate analyses, female sex (p < 0.001), age ≥50 years (p = 0.023), rural residence (p < 0.001), excessive alcohol intake (p = 0.002), current cigarette smoking (p < 0.001), level of education (p < 0.001), regular consumption of soft drinks (p < 0.001) and unemployment (p = 0.043) were found to be positively and significantly associated with obesity. In the multivariate logistic regression analysis, female sex (p < 0.001), unemployment (p = 0.012) and level of education (p < 0.001) were found to be independent determinants of obesity.

Conclusion

We found that female sex, educational attainment, unemployment and current cigarette smoking were positively associated with obesity among the study participants. Lifestyle changes, poverty reduction and public education are urgently needed to address the growing obesity epidemic in rural areas of South Africa.

Insulin receptor-insulin interaction kinetics using multiplex surface plasmon resonance

Type 2 diabetes affects millions of people worldwide, and measuring the kinetics of insulin receptor-insulin interactions is critical to improving our understanding of this disease. In this paper, we describe, for the first time, a rapid, real-time, multiplex surface plasmon resonance (SPR) assay for studying the interaction between insulin and the insulin receptor ectodomain, isoform A (eIR-A). We used a scaffold approach in which anti-insulin receptor monoclonal antibody 83-7 (Abcam, Cambridge, UK) was first immobilized on the SPR sensorchip by amine coupling, followed by eIR-A capture. The multiplex SPR system (ProteOn XPR36™, Bio-Rad Laboratories, Hercules, CA) enabled measurement of replicate interactions with a single, parallel set of analyte injections, whereas repeated regeneration of the scaffold between measurements caused variable loss of antibody activity. Interactions between recombinant human insulin followed a two-site binding pattern, consistent with the literature, with a high-affinity site (dissociation constant K(D1)  = 38.1 ± 0.9 nM) and a low-affinity site (K(D2)  = 166.3 ± 7.3 nM). The predominantly monomeric insulin analogue Lispro had corresponding dissociation constants K(D1)  = 73.2 ± 1.8 nM and K(D2)  = 148.9 ± 6.1 nM, but the fit to kinetic data was improved when we included a conformational change factor in which the high-affinity site was converted to the low-affinity site. The new SPR assay enables insulin-eIR-A interactions to be followed in real time and could potentially be extended to study the effects of humoral factors on the interaction, without the need for insulin labeling.

The potential role of GLUT4 transporters and insulin receptors in the hypoglycaemic activity of Ficus lutea acetone leaf extract

Background

Some Ficus species have been used in traditional African medicine in the treatment of diabetes. The antidiabetic potential of certain species has been confirmed in vivo but the mechanism of activity remains uncertain.

The aim was to investigate the hypoglycaemic potential of ten Ficus species focussing on glucose uptake, insulin secretion and the possible mechanism of hypoglycaemic activity.

Methods

The dried and ground leaves of ten Ficus species were extracted with acetone. The dried acetone extract was reconstituted with DMSO to a concentration of 100 mg/ml which was then serially diluted and used to assay for glucose uptake in muscle, fat and liver cells, and insulin secretion in pancreatic cells.

Results

Only the F. lutea extract was able to modulate glucose metabolism. In comparison to insulin in the primary muscle cells, the glucose uptake ability of the extract was 33% as effective. In the hepatoma cell line, the extract was as effective as metformin in decreasing extracellular glucose concentration by approximately 20%. In the pancreatic insulin secretory assay, the extract was 4 times greater in its secretory activity than commercial glibenclamide. With F. lutea extract significantly increasing glucose uptake in the primary muscle cells, primary fat cells, C2C12 muscle and H-4-II-E liver cells, the extract may act by increasing the activity of cell surface glucose transporters. When the 3T3-L1 pre-adipocytes were compared to the primary muscle, primary fat and C2C12 cells, the differences in the former’s ability to transport glucose into the cell may be due to the absence of the GLUT4 transporter, which on activation via the insulin receptor decreases extracellular glucose concentrations. Because the pre-adipocytes failed to show any active increase in glucose uptake, the present effect has to be linked to the absence of the GLUT4 transporter.

Conclusion

Only F. lutea possessed substantial in vitro activity related to glucose metabolism. Based on the effect produced in the various cell types, F. lutea also appears to be a partial agonist/antagonist of the insulin cell membrane receptor. While the clinical effectiveness of F. lutea is not known, this plant species does possess the ability to modify glucose metabolism.

Prevalence and correlates of complementary and alternative medicine use among diabetic patients in Beirut, Lebanon: a cross-sectional study

Background

Patients with Type 2 Diabetes Mellitus (T2DM) are increasingly using complementary and alternative medicine (CAM) therapies due to difficulty in adhering to the therapeutic regimens and lifestyle changes necessary for disease management. Little is known about the prevalence and mode of CAM use among patients with T2DM in Lebanon.

Objective

To assess the prevalence and modes of CAM use among patients with T2DM residing in Beirut, Lebanon.

Methods

A cross-sectional survey of T2DM patients was conducted on patients recruited from two major referral centers in Beirut- a public hospital and a private academic medical center. In a face-to-face interview, participants completed a questionnaire comprised of three sections: socio-demographic, diabetes characteristics and types and modes of CAM use. Descriptive statistics, univariate and multivariate logistic regression analyses were utilized to assess the prevalence and correlates of CAM use, as well as whether the use was complementary or alternative to mainstream medicine. The main outcome in this study, CAM use, was defined as using CAM at least once since diagnosis with T2DM.

Results

A total of 333 T2DM patients completed the survey (response rate: 94.6%). Prevalence of CAM use since diagnosis with the disease was 38%. After adjustment, CAM use was significantly associated with a “married” status, a longer duration of T2DM, the presence of disease complications, and a positive family history of the disease. Folk foods and herbs were the most commonly used CAM followed by natural health products. One in five patients used CAM as alternative to conventional treatment. Only 7% of CAM users disclosed the CAM use to their treating physician. Health care practitioners were the least cited (7%) as influencing the choice of CAM among users.

Conclusion

The use of CAM therapies among T2DM patients in Lebanon is prevalent. Decision makers and care providers must fully understand the potential risks and benefits of CAM therapies to appropriately advise their patients. Attention must be dedicated to educating T2DM patients on the importance of disclosing CAM use to their physicians especially patients with a family history of diabetes, and those who have had the disease for a long time.

Combination therapy: a new strategy to manage diabetes and its complications

Diabetes mellitus is the most common metabolic disorder. The major cause of mortality and morbidity here is due to the complications caused by increased glucose concentrations. All the available commercial antidiabetic drugs are associated with side effects. The combination therapy could be a new and highly effective therapeutic strategy to manage hyperglycemia. Combination of commercial drugs with phytochemicals may reduce the side effects caused by these synthetic drugs. Herbal products have been thought to be inherently safe, because of their natural origin and traditional use rather than based on systemic studies. New formulation and cocrystallisation strategies need to be adopted to match the bioavailability of the drug and the phytochemical. This review describes in detail, the observed synergy and mechanism of action between phytochemicals and synthetic drugs in effectively combating. The mode of action of combination differs significantly than that of the drugs alone; hence isolating a single component may lose its importance thereby simplifying the task of pharma industries.

Development and characterization of glimepiride nanocrystal formulation and evaluation of its pharmacokinetic in rats

In this paper, orally nanocrystal capsules were produced using nanocrystal formulations in order to optimize dissolution properties of poorly soluble drug glimepiride and improve its bioavailability. The important preparation variables, such as stabilizers, the power input and the time length of ultrasonication on the mean particle size and polydispersity index were investigated systematically, and the optimal values were 0.2% glimepiride (w/v), 1.2% Lipoid S100, 0.6% PEG 6000 (w/v), 0.6% PVPK 30 (w/v), 500 W and 2 min, respectively. Characterization of glimepiride nanocrystal was carried out by X-ray powder diffractometry, differential scanning calorimetry and scanning electron microscopy. In vitro dissolution test, the nanocrystal-loaded capsules of glimepiride showed an evident increase in dissolution rate compared to micronized and market capsules. The in vivo studies demonstrated that a marked enhancement of bioavailability of nanocrystal-loaded capsules was superior compared to the marketed formulation and microcrystal-loaded capsules, which may reduce the risk of side effect by allowing a reduction in either the dose or its frequency of administration.

Development and characterization of lecithin stabilized glibenclamide nanocrystals for enhanced solubility and drug delivery

Novel LNCs (lipid nanocrystals) were developed with an aim to improve the solubility, stability and targeting efficiency of the model drug glibenclamide (GLB). PEG 20000, Tween 80 and soybean lecithin were used as polymer, surfactant and complexing agent, respectively. GLB nanocrystals (NCs) were prepared by precipitation process and complexed using hot and cold melt technique. The LNCs were evaluated by drug loading, saturation solubility (SL), optical clarity, in vitro dissolution, solid state characterization, in vivo and stability analysis. LNCs exhibited a threefold increase in SL and a higher dissolution rate than GLB. The percentage dissolution efficiency was found to decrease with increase in PEG 20000. The average particle size was in the range of 155-842 nm and zeta potential values tend to increase after complexation. X-ray powder diffractometry and differential scanning calorimetry results proved the crystallinity prevailed in the samples. Spherical shaped particles (<1000 nm) with a lipid coat on the surface were observed in scanning electron microscopy analysis. Fourier transform infrared results proved the absence of interaction between drug and polymer and stability study findings proved that LNCs were stable. In vivo study findings showed a decrease in drug concentration to pancreas in male Wistar rats. It can be concluded that LNCs are could offer enhanced solubility, dissolution rate and stability for poorly water soluble drugs. The targeting efficiency of LNCs was decreased and further membrane permeability studies ought to be carried out.

Solid-state characterization studies and effect of PEG 20000 and P90G on particle size reduction and stability of complexed glimepiride nanocrystals

OBJECTIVE

The objective of the present study is to formulate and characterize the properties of complexed glimepiride nanocrystals (GLP) by various techniques at different stages of its development, and to study the effect of PEG 20000 and P90G on particle size reduction and stability of nanocrystals.

METHOD

Precipitated (GLP-PEG) and complexed NCs (GLP-PEG-P90G) of glimepiride were characterized for particle size, size distribution, zeta potential and stability assessment using photon correlation spectroscopy (PCS). The crystallinity was analyzed using differential scanning calorimetry (DSC) and X-ray powder diffraction spectroscopy (XRPD). The surface morphology and chemical stability were assessed by means of scanning electron microscopy (SEM) and infrared spectroscopy (FTIR).

RESULTS

A formulation with drug-polymer ratio of 1:1 was most ideal in developing stable NCs as it exhibited smaller particle size and high stability. A high zeta potential was observed in all NCs after complexation indicating improved stability. DSC and XRPD studies showed no change in crystallinity after complexation. SEM analysis of complexed NCs showed presence of spherical shape particles (size below 1 μm) with a lipid coat on the surface. Stability studies on optimized formulation (F1) revealed no change in particle size during 3-month period. FTIR studies prove that the chemical identity of GLP was preserved in the samples and the formulation was stable.

CONCLUSION

Solid-state characterization studies reveal that complexed GLP NCs are promising carriers for drug delivery and they can be safely and effectively used in design of various formulations. Also, PEG 20000 and P90G are excellent polymer and lipid for particle size reduction (nanonization) and stabilization of nanocrystals.

Evaluation of the inhibition of carbohydrate hydrolysing enzymes, antioxidant activity and polyphenolic content of extracts of ten African Ficus species (Moraceae) used traditionally to treat diabetes

BACKGROUND

Some Ficus species have been used in traditional African medicine in the treatment of diabetes. The antidiabetic potential of certain species has been confirmed in vivo but the mechanism of activity remains uncertain. The aim of this study was to determine the activity and to investigate the mechanism of antidiabetic activity of ten selected Ficus species through inhibition of α-amylase and α-glucosidase activity, and the possible relationship between these activities, the total polyphenolic content and the antioxidant activity.

METHODS

Dried acetone leaf extracts were reconstituted with appropriate solvents and used to determine total polyphenolic content antioxidant activity, α-amylase and α-glucosidase inhibitory activity.

RESULTS

The crude acetone extract of F. lutea had the highest polyphenolic content (56.85 ± 1.82 mg GAE/g of dry material) and the strongest antioxidant activity with a TEAC value of 4.80 ± 0.90. The antioxidant activity of the acetone extracts of the Ficus species may not be ascribed to total polyphenolic content alone. The crude extract at a concentration of 0.5 mg/ml of F. lutea (64.3 ± 3.6%) had the best α-glucosidase (sucrase) inhibitory activity. The EC50 of F. lutea (290 ± 111 μg/ml) was not significantly different from that of F. sycomorus (217 ± 69 μg/ml). The α-amylase inhibitory activity of F. lutea (95.4 ± 1.2%) at a concentration of 1 mg/ml was the highest among the Ficus species screened. The EC50 for F. lutea (9.42 ± 2.01 μ g/ml), though the highest, was not significantly different (p < 0.05) from that of F. craterostoma and F. natalensis. It was apparent that the crude acetone extract of F. lutea is a partially non-competitive inhibitor of α-amylase and α-glucosidase. Based on correlation coefficients polyphenolics may be responsible for α-glucosidase activity but probably not for α-amylase activity.

CONCLUSION

Antidiabetic activity potential via inhibition of α-amylase and α-glucosidase was discovered in Ficus lutea which has not been previously reported. The acetone extract of the leaves was high in total polyphenolic content and antioxidant activity, and was a potent inhibitor of α-amylase activity. Research is underway to isolate the active compound(s) responsible for the antidiabetic activity and to confirm the in vitro antidiabetic activity and to investigate in vitro toxicity.

Excess aldosterone-induced changes in insulin signaling molecules and glucose oxidation in gastrocnemius muscle of adult male rat

Emerging evidences demonstrate that excess aldosterone and insulin interact at target tissues. It has been shown that increased levels of aldosterone contribute to the development of insulin resistance and thus act as a risk factor for the development of type-2 diabetes mellitus. However, the molecular mechanisms involved in this scenario are yet to be identified. This study was designed to assess the dose-dependent effects of aldosterone on insulin signal transduction and glucose oxidation in the skeletal muscle (gastrocnemius) of adult male rat. Healthy adult male albino rats of Wistar strain (Rattus norvegicus) weighing 180-200 g were used in this study. Rats were divided into four groups. Group I: control (treated with 1 % ethanol only), group II: aldosterone treated (10 μg /kg body weight, twice daily for 15 days), group III: aldosterone treated (20 μg /kg body weight, twice daily for 15 days), and group IV: aldosterone treated (40 μg/kg body weight, twice daily for 15 days). Excess aldosterone caused glucose intolerance in a dose-dependent manner. Serum insulin and aldosterone were significantly increased, whereas serum testosterone was decreased. Aldosterone treatment impaired the rate of glucose uptake, oxidation, and insulin signal transduction in the gastrocnemius muscle through defective expression of IR, IRS-1, Akt, AS160, and GLUT4 genes. Phosphorylation of IRS-1, β-arrestin-2, and Akt was also reduced in a dose-dependent manner. Excess aldosterone results in glucose intolerance as a result of impaired insulin signal transduction leading to decreased glucose uptake and oxidation in skeletal muscle. In addition to this, it is inferred that excess aldosterone may act as one of the causative factors for the onset of insulin resistance and thus increased incidence of type-2 diabetes.

In vitro studies of Gynura divaricata (L.) DC extracts as inhibitors of key enzymes relevant for type 2 diabetes and hypertension

AIM OF THE STUDY

To evaluate traditionally used herb, Gynura divaricata (L.) DC (Bai Bei San Qi) as in vitro inhibitors of key enzymes involved in the pathogenesis of hyperglycemia and hypertension. We also determined the distribution of enzyme inhibitory activities in different aqueous and non-aqueous extracts.

MATERIALS AND METHODS

The water extract (extract 1) from the aerial parts of Gynura divaricata (L.) was prepared first and then partitioned sequentially with n-butanol, ethyl acetate, and macroporous adsorptive resin (HPD-40) to yield extracts 2-4; the remaining water phase was named extract 5. Angiotensin-1 converting enzyme (ACE), α-amylase α-glycosidase inhibitory activities of the extracts were determined in vitro and chemical composition including total sugar, protein, flavonoid and total alkaloids in the extract were also evaluated.

RESULTS

The water extract of this herb significantly inhibited (p<0.05) ACE activity (IC(50)=0.37 mg/ml) and showed a moderate potential hypoglycemic effect via in vitro α-amylase (IC(50)=1.36 mg/ml) and α-glycosidase (IC(50)=2.17 mg/ml) inhibition in dose-dependent manner. Further partitioning of the water extract (extracts 2-4) resulted in higher α-amylase inhibitory activities in extract 2 and 3. For α-glycosidase inhibition, extract 3 gave the highest inhibition. ACE inhibitory activities of the extracts were not improved by partitioning. Sugar, protein, flavonoid and alkaloid were found in water extract but only a small portion was partitioned in the n-butanol extract. However, a large portion of the flavonoids and alkaloids were found in ethyl acetate extract.

CONCLUSION

The results confirmed potential empirical use of Gynura divaricata (L.) DC for the management of hyperglycemia as well as hypertension. The active compounds for inhibition of α-amylase and α-glycosidase inhibition were flavonoids and alkaloids while ACE inhibition probably resulted from synergic effects of all the herb compounds.

Genetic variants in peroxisome proliferator-activated receptor-γ and retinoid X receptor-α gene and type 2 diabetes risk: a case-control study of a Chinese Han population

BACKGROUND

The serum levels of adiponectin are paradoxically decreased in obesity and may play important roles in the development of type 2 diabetes mellitus (T2DM). Potentially functional polymorphisms in the peroxisome proliferator-activated receptor-γ (PPAR-γ) and retinoid X receptor-α (RXR-α) genes may alter T2DM risks by increasing the human adiponectin promoter activity in cells. Therefore, we hypothesized that single nucleotide polymorphisms (SNPs) in PPAR-γ and RXR-α were associated with risk of T2DM. To test this hypothesis, three potentially functional SNPs of PPAR-γ and four of RXR-α with a minor allele frequency of ≥ 0.05 in the Chinese Han population were identified from the National Center for Biotechnology Information dbSNPs database to evaluate their association with T2DM.

METHODS

Polymerase chain reaction-restriction fragment length polymorphism was performed to test the genotypes in T2DM patients (n = 540) and normal controls (n = 604).

RESULTS

The variant genotypes rs2920502CC, rs3856806CT, rs3856806CT/TT, and rs4240711AG/GG were associated with T2DM. Furthermore, the prevalences of haplotype GTC and CTG in PPAR-γ and GTAC in RXR-α were less frequent in cases (17.1%, 2.6%, and 2.4%, respectively) than in controls (22.3%, 3.8%, and 6.6%, respectively), whereas GTGT in RXR-α was more frequent in cases (6.9%) than in controls (4.4%) (P < 0.05 for both two-sided χ(2) test and thousand times permutation tests). Patients with genotype CT/TT of rs3856806 and genotype AG/GG of rs4240711 had higher levels of serum adiponectin than those with the genotype CC and genotype AA (P = 0.026 and 0.021, respectively). Model X2 X5 X6 X7 (rs3856806, rs3132291, rs4240711, and rs4842194) was the best model with the highest test balanced accuracy (0.5764) (cross-validation consistency = 10/10) in the multifactor dimensionality reduction method.

CONCLUSIONS

The PPAR-γ and RXR-α gene variants associated with the development of T2DM in this study must be investigated in a larger population to reveal any potential effects on metabolism.