Insulin-mimetic Agent Research Articles

Hydrazone-flavonol based oxidovanadium(V) complexes: Synthesis, characterization and antihyperglycemic activity of chloro derivative in vivo

Wet synthesis approach afforded four new heteroleptic mononuclear neutral diamagnetic oxidovanadium(V) complexes, comprising salicylaldehyde-based 2-furoic acid hydrazones and a flavonol coligand of the general composition [VO(fla)(L-ONO)]. The complexes were comprehensively characterized, including chemical analysis, conductometry, infrared, electronic, and mass spectroscopy, as well as 1D 1H and proton-decoupled 13C(1H) NMR spectroscopy, alongside extensive 2D 1H1H COSY, 1H13C HMQC, and 1H13C HMBC NMR analyses. Additionally, the quantum chemical properties of the complexes were studied using Gaussian at the B3LYP, HF, and M062X levels on the 6–31++g(d,p) basis sets. The interaction of these hydrolytically inert vanadium complexes and the BSA was investigated through spectrofluorimetric titration, synchronous fluorimetry, and FRET analysis in a temperature-dependent manner, providing valuable thermodynamic insights into van der Waals interactions and hydrogen bonding. Molecular docking was conducted to gain further understanding of the specific binding sites of the complexes to BSA. Complex 2, featuring a 5-chloro-substituted salicylaldehyde component of the hydrazone, was extensively examined for its biological activity in vivo. The effects of complex administration on biochemical and hematological parameters were evaluated in both healthy and diabetic Wistar rats, revealing antihyperglycemic activity at millimolar concentration. Furthermore, histopathological analysis and bioaccumulation studies of the complex in the brain, kidneys, and livers of healthy and diabetic rats revealed the potential for further development of vanadium(V) hydrazone complexes as antidiabetic and insulin-mimetic agents.

Activity Test of Cassia alata L. Leaf Extract on Kidney Histopathology Damage Score of Diabetes Mellitus Model

Diabetic nephropathy is a disease experienced by diabetic patients. In this disease, damage to the glomerulus occurs. The administration of antidiabetic drugs tends to cause unwanted side effects, so there is a need for alternative treatment from herbs, one of which is Cassia alata L. Cassia alata L. leaves have chemical content such as flavonoids, alkaloids, tannins, and saponins. Flavonoids reduce blood glucose levels by increasing insulin secretion and mimetic agents, tannins slow carbohydrate digestion and saponins repair pancreatic beta cells and increase glycogen in the liver. This study aims to determine the effect of Cassia alata L. ethanol on the histopathology damage score of male white rat kidney (Rattus norvegicus) induced by streptozotocin. The test animals used were 30 male white rats divided into six treatment groups, each group consisting of five male white rats, namely the normal control group, negative control group, positive control group, treatment group with doses of 500 mg/kg BW, 600 mg/kg BW, and 700 mg/kg BW. The parameters evaluated were kidney tissue damage score and histopathology image analysis. The results showed that the ethanol extract of Cassia alata L. leaves contain alkaloids, flavonoids, saponins, and tannins. The ethanol extract of Cassia alata L. leaves in doses of 500 mg/kg BW, 600 mg/kg BW and 700 mg/kg BW has the activity of reducing the score of kidney tissue damage in male white rats and a dose of 700 mg/kg BW is the best dose in reducing the score of kidney tissue damage in diabetes mellitus models with a score of 2.

Protonated amino alcohols as cations in synthesis of vanadium(V) complexes with Schiff base ligands as potential insulin-mimetic agents

Series of ionic dioxidovanadium(V) complexes with Schiff base ligands based on 2-hydroxybenzhydrazide and substituted salicylaldehydes were synthesized and described. As cations, the organic compounds like 2-aminoethanol (AMET) and 3-amino-1-propanol (AMPR) were used. The complexes of general formula HAMET[VO2L] and HAMPR[VO2L] (where L = ONO-donor Schiff base ligand) were characterized by X-ray single crystal structure measurements as well as elemental analysis, IR and UV–Vis spectroscopy. The complexes were very well soluble in water in contrast to their neutral analogues, what gives the opportunity to measure their stability in this solvent. The stability was also tested at pH = 2 by UV–Vis spectra measurement. The results were compared to neutral vanadium complexes with Schiff base ligands, previously studied as potential insulin-mimetic agents.

Evidence of Insulin-Sensitizing and Mimetic Activity of the Sesquiterpene Quinone Avarone, a Protein Tyrosine Phosphatase 1B and Aldose Reductase Dual Targeting Agent from the Marine Sponge Dysidea avara.

Type 2 diabetes mellitus (T2DM) is a complex disease characterized by impaired glucose homeostasis and serious long-term complications. First-line therapeutic options for T2DM treatment are monodrug therapies, often replaced by multidrug therapies to ensure that non-responding patients maintain target glycemia levels. The use of multitarget drugs instead of mono- or multidrug therapies has been emerging as a main strategy to treat multifactorial diseases, including T2DM. Therefore, modern drug discovery in its early stages aims to identify potential modulators for multiple targets; for this purpose, exploration of the chemical space of natural products represents a powerful tool. Our study demonstrates that avarone, a sesquiterpene quinone obtained from the sponge Dysidea avara, is capable of inhibiting in vitro PTP1B, the main negative regulator of the insulin receptor, while it improves insulin sensitivity, and mitochondria activity in C2C12 cells. We observe that when avarone is administered alone, it acts as an insulin-mimetic agent. In addition, we show that avarone acts as a tight binding inhibitor of aldose reductase (AKR1B1), the enzyme involved in the development of diabetic complications. Overall, avarone could be proposed as a novel natural hit to be developed as a multitarget drug for diabetes and its pathological complications.

Ionic Dioxidovanadium(V) Complexes with Schiff-Base Ligands as Potential Insulin-Mimetic Agents—Substituent Effect on Structure and Stability

Four dioxidovanadium(V) complexes with Schiff-base ligands based on 2-hydroxybenzhydrazide with four different substituted salicylaldehydes (5-chlorosalicylaldehyde, 3,5-dichlorosalicylaldehyde, 5-nitrosalicylaldehyde, 3-bromo-5-chlorosalicylaldehyde) were synthesized and described, by using V2O5 and triethylamine. The single crystal X-ray structure measurements as well as elemental analyses and IR spectra confirmed the formulas of the ionic complexes with a protonated triethylamine acting as counterion, HTEA[VO2(L)] (HL = Schiff-base ligand). The kinetic stability of the complexes at pH = 2 and 7 was discussed with respect to the neutral vanadium(V) complexes previously studied as potential insulin-mimetic agents. A correlation between the substituents in an aromatic ring of the Schiff-base ligands with crystal packing, and also with the stability of the compounds, was presented.

Synthesis, Characterization, and In Vitro Insulin-Mimetic Activity Evaluation of Valine Schiff Base Coordination Compounds of Oxidovanadium(V).

Type 2 diabetes became an alarming global health issue since the existing drugs do not prevent its progression. Herein, we aimed to synthesize and characterize a family of oxidovanadium(V) complexes with Schiff base ligands derived from L-/D-valine (val) and salicylaldehyde (sal) or o-vanillin (van) as insulin-mimetic agents and to assess their potential anti-diabetic properties. Two new oxidovanadium(V) complexes, [{VVO(R-salval)(H2O)}(μ2-O){VVO(R-salval)}] and [{VVO(R-vanval)(CH3OH)}2(μ2-O)], and their S-enantiomers were synthesized and characterized. The compounds exhibit optical activity as shown by crystallographic and spectroscopic data. The stability, the capacity to bind bovine serum albumin (BSA), the cytotoxicity against human hepatoma cell line, as well as the potential anti-diabetic activity of the four compounds are investigated. The synthesized compounds are stable for up to three hours in physiological conditions and exhibit a high capacity of binding to BSA. Furthermore, the synthesized compounds display cytocompatibility at biologically relevant concentrations, exert anti-diabetic potential and insulin-mimetic activities by inhibiting the α-amylase and protein tyrosine phosphatase activity, and a long-term increase of insulin receptor phosphorylation compared to the insulin hormone. Thus, the in vitro anti-diabetic potential and insulin-mimetic properties of the newly synthesized oxidovanadium(V) compounds, correlated with their cytocompatibility, make them promising candidates for further investigation as anti-diabetic drugs.

Reviews on Plants Gum and Mucilage I: The Composition and Pharmacological Significance of Turmeric (Curcuma longa) Rhizomes Polysaccharides and Mucilage/their Aqueous Extracts Commercial Products

The utilization of plants’ polysaccharide as hydrocolloid materials within the last four decades, had drawn a significant attention due to their therapeutic and pharmaceutical applications. Among the Zingiberaceae family of plants, Curcuma longa L. rhizomes polyphenolic product like curcuminoids, flavonoids, turmerones and other polyphenolics had gained extensive investigation efforts and reported intensively. Curcuma longa L. rhizomes polysaccharide type mucilage hasn’t received considerable attention by academic authors and researchers. In this survey, we tried to highlight this type of phytomolecules through exploring the issued research articles focusing on their pharmacological importance. Reference books, Scopus, PubMed, Web of Science bibliographic databases and Google scholar scientific search engines besides other open access researches sited on Google were screened for plant polysaccharides significances and uses in addition to their pharmacological activities. Screening was done using six different groups of keywords. All results found by keywords were reviewed and none-relevant articles were excluded by outcome of interests and researcher boundaries of study through a systematic method. It has been stated that, both mucilage and gums types of plants’ polysaccharides had gained great investigation efforts in recent years. Concerning C. longa L. rhizomes; four different polysaccharides had been reported. They were to be isolated, purified and characterized from their polysaccharide mucilage aqueous extract then labelled as Ukonans A, B, C and D. Several biological influences were studied for these polysaccharide compounds and mixtures as well as for their aqueous extracts fractions, including immune busting, anti-inflammatory, anti-ulcerogenic agent, insulin mimetic hypoglycemic agent, anticancer/chemo-preventive and anti-obesity agent activities. Reviewed articles encouges us to conclude the potentiality of investigation of turmeric polysaccharides as pharmaceutical additive/and or co-therapy for several pathological conditions.

Molecular Docking Studies and Pharmacophore Modeling of Some Insulin Mimetic Agents from Herbal Sources: A Rational Approach towards Designing of Orally Active Insulin Mimetic Agents

Background:: Many herbal drugs have been found to possess oral insulin mimetic property as evidenced from the literature. Although, to date there is no efficient, synthetic orally active insulin-mimetic drug available clinically. Computer-Aided Drug Design (CADD) may help in the development of such agents through Pharmacophore modeling. Objective:: The present work is aimed at the In-silico designing of Pharmacophore that defines the structural requirements of a molecule to possess oral insulin-mimetic properties. Methods:: A set of 16 orally active insulin-mimetic natural compounds available through literature was used to develop a structure-based pharmacophore in a “three-step filtration process” comprised of Lipinski’s rule of 5, Minimum binding energy with the receptor and Ghose filter to the Lipinski’s rule for oral bioavailability of the drugs. The selected ligands were docked with phosphorylated insulin receptor tyrosine kinase in complex with peptide substrate and ATP analog (PDB ID: 1IR3) using Autodock 4.2 and their interaction with the receptor was analyzed followed by the generation of shared and merged feature pharmacophore by Ligandscout 4.2.1. Results:: There are three important structural features that contribute to interaction with the active site of the insulin receptor: these are hydrogen bond donor groups, hydrogen bond acceptor groups and hydrophobic interactions. It is important to note that positive or negative ionizable groups or the presence of aromatic rings are not important for the activity. Conclusion:: Taking a clue from the developed pharmacophore, one may design new lead having necessary groups required for the insulin-mimetic activity that can be elaborated synthetically to get a series of compounds with possible oral insulin-mimetic activity.

Hydroxyoleoside-type seco-iridoids from Symplocos cochinchinensis and their insulin mimetic activity

As part of an ongoing study of new insulin mimetic agents from medicinal plants, the 70% EtOH extract of Symplocos cochinchinensis was found to have a stimulatory effect on glucose uptake in 3T3-L1 adipocyte cells. The intensive targeted isolation of this active extract resulted in ten new hydroxyoleoside-type compounds conjugated with a phenolic acid and monoterpene (1–6 and 8–11), as well as four known compounds (7 and 12–14). The chemical structures of the new compounds were determined based on spectroscopic data analysis (1H and 13C NMR, HSQC, HMBC, NOESY and MS). The absolute configurations of the isolated compounds were determined by electronic circular dichroism (ECD) analysis of derivatives obtained after a series of reactions, such as those with dirhodium (ІІ) tetrakis (trifluoroacetate) and dimolybdenum (ІІ) tetraacetate. In vitro, compounds 3, 7 and 8 moderately increased the 2-deoxy-2-[(7-nitro-2,1,3-benzoxadiazol-4-yl)amino]-D-glucose (2-NBDG) uptake level in differentiated 3T3-L1 adipocytes. For further studies, we evaluated their effects on the expression of glucose transporter-4 (GLUT4), its translocation, protein tyrosine phosphatase 1B (PTP1B) inhibition and expression of phosphorylated Akt. Our results strongly suggest that the traditional uses of this plant can be described as active constituents by hydroxyoleoside-type compounds.

The Antidiabetic Agent Sodium Tungstate Induces Abnormal Glycogen Accumulation in Renal Proximal Tubules from Diabetic IRS2-Knockout Mice.

The kidney is an insulin-sensitive organ involved in glucose homeostasis. One major effect of insulin is to induce glycogen storage in the liver and muscle. However, no significant glycogen stores are detected in normal kidneys, but diabetic subjects present a characteristic renal histopathological feature resulting from extensive glycogen deposition mostly in nonproximal tubules. The mechanism of renal glycogen accumulation is yet poorly understood. Here, we studied in situ glycogen accumulation in the kidney from diabetic IRS2-knockout mice and the effect of the insulin-mimetic agent sodium tungstate (NaW). IRS2-knockout mice displayed hyperglycemia and hyperinsulinemia. NaW only normalized glycemia. There was no evident morphological difference between kidneys from untreated wild-type (WT), NaW-treated WT, and untreated IRS2-knockout mice. However, NaW-treated IRS2-knockout mice showed tubular alterations resembling clear cells in the cortex, but not in the outer medulla, that were correlated with glycogen accumulation. Immunohistochemical detection of the gluconeogenic enzyme phosphoenolpyruvate carboxykinase, mostly expressed by renal proximal tubules, showed that altered tubules were of proximal origin. Our preliminary study suggests that IRS2 differentially regulates glycogen accumulation in renal tubules and that NaW treatment in the context of IRS2 ablation induces abnormal glycogen accumulation in cortical proximal tubules.

Synthesis, biological activity and toxicity of chromium(III) metformin complex as potential insulin-mimetic agent in C57BL/6 mice

As an oral hypoglycemic agent, metformin (Met) has become a best-selling inexpensive drug worldwide. In this thesis, [Cr(metformin)3] (CrMet) complex was synthesized and characterized by elemental analysis (EA), electrospray ionization mass spectrometry (ESI-MS), nuclear magnetic resonance (NMR), infrared (IR), UV-visible (UV-vis), and molar conductivity. Meanwhile, the molecule structure of CrMet complex was optimized using Gaussian 09. Considering the therapeutic effect of Met and Met/Cr(III) complex on type 2 diabetes mellitus (T2DM), the biological activities of CrMet in streptozocin (STZ)-induced diabetic mice were evaluated in detail from the aspects of fasting blood glucose (FBG), fasting serum insulin (FINS), triglyceride (TG), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-c), and high-density lipoprotein cholesterol (HDL-c) levels. These results indicated that CrMet had beneficial function on blood glucose (BG) and lipid metabolism for diabetes. Additionally, the results of cytotoxicity and toxicity experiments showed that CrMet had no damage to cells and relatively high safety in mice. It maybe a potential candidate as a therapeutic agent in T2DM.

Effects of local vanadium delivery on diabetic fracture healing.

This study evaluated the effect of local vanadyl acetylacetonate (VAC), an insulin mimetic agent, upon the early and late parameters of fracture healing in rats using a standard femur fracture model. Mechanical testing, and radiographic scoring were performed, as well as histomorphometry, including percent bone, percent cartilage, and osteoclast numbers. Fractures treated with local 1.5 mg/kg VAC possessed significantly increased mechanical properties compared to controls at 6 weeks post-fracture, including increased torque to failure (15%; p = 0.046), shear modulus (89%; p = 0.043), and shear stress (81%; p = 0.009). The radiographic scoring analysis showed increased cortical bridging at 4 weeks and 6 weeks (119%; p = 0.036 and 209%; p = 0.002) in 1.5 mg/kg VAC treated groups. Histomorphometry of the fracture callus at days 10 and 14 showed increased percent cartilage (121%; p = 0.009 and 45%; p = 0.035) and percent mineralized tissue (66%; p = 0.035 and 58%; p = 0.006) with local VAC treated groups compared to control. Additionally, fewer osteoclasts were observed in the local VAC treated animals as compared to controls at day 14 (0.45% ± 0.29% vs. 0.83% ± 0.36% of callus area; p = 0.032). The results suggest local administration of VAC acts to modulate osteoclast activity and increase percentage of early callus cartilage, ultimately enhancing mechanical properties comparably to non-diabetic animals treated with local VAC. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:2174-2180, 2017.

The adipogenic potential of Cr(III). A molecular approach exemplifying metal-induced enhancement of insulin mimesis in diabetes mellitus II

Insulin resistance is identified through numerous pathophysiological conditions, such as Diabetes mellitus II, obesity, hypertension and other metabolic syndromes. Enhancement of insulin action and\\or its complete replacement by insulin-enhancing or insulin-mimetic agents seems to improve treatment of metabolic diseases. Over the last decades, intensive research has targeted the investigation of such agents, with chromium emerging as an important inorganic cofactor involved in the requisite metabolic chemistry. Chromium in its trivalent state has been shown to play a central role in carbohydrate metabolism by enhancing insulin signaling, action, and thus the sensitivity of insulin-sensitive tissues. A very likely link between diabetes and obesity is the adipose tissue, which stores energy in the form of triglycerides and releases free fatty acids. To date, there is paucity of information on the exact mechanism of the chromium effect concerning insulin-activated molecular paths, such as adipogenesis. The aim of the present study is to delve into such an effect by employing a well-defined form of chromium (Cr(III)-citrate) on the a) survival of pre- and mature adipocytes (3T3-L1), b) endogenous cell motility, and c) insulin-enhancing adipogenic capacity. The emerging results suggest that Cr(III)-citrate a) is (a)toxic in a concentration- and time-dependent manner, b) has no influence on cell motility, c) can induce 3T3-L1 pre-adipocyte differentiation into mature adipocytes through elevation of tissue specific biomarker levels (PPAR-γ, GLUT 4 and GCK), and d) exemplifies structurally-based metal-induced adipogenesis as a key process contributing to the development of future antidiabetic metallodrugs.

Zinc has insulin-mimetic properties which enhance spinal fusion in a rat model

Background ContextPrevious studies have found that insulin or insulin-like growth factor treatment can stimulate fracture healing in diabetic and normal animal models, and increase fusion rates in a rat spinal fusion model. Insulin-mimetic agents, such as zinc, have demonstrated antidiabetic effects in animal and human studies, and these agents that mimic the effects of insulin could produce the same beneficial effects on bone regeneration and spinal fusion. PurposeThe purpose of this study was to analyze the effects of locally applied zinc on spinal fusion in a rat model. Study Design/SettingInstitutional Animal Care and Use Committee-approved animal study using Sprague-Dawley rats was used as the study design. MethodsThirty Sprague-Dawley rats (450–500 g) underwent L4–L5 posterolateral lumbar fusion (PLF). After decortication and application of approximately 0.3 g of autograft per side, one of three pellets were added to each site: high-dose zinc calcium sulfate (ZnCaSO4), low-dose ZnCaSO4 (half of the high dose), or a control palmitic acid pellet (no Zn dose). Systemic blood glucose levels were measured 24 hours postoperatively. Rats were sacrificed after 8weeks and the PLFs analyzed qualitatively by manual palpation and radiograph review, and quantitatively by micro-computed tomography (CT) analysis of bone volume and trabecular thickness. Statistical analyses with p-values set at .05 were accomplished with analysis of variance, followed by posthoc tests for quantitative data, or Mann-Whitney rank tests for qualitative assessments. ResultsCompared with controls, the low-dose zinc group demonstrated a significantly higher manual palpation grade (p=.011), radiographic score (p=.045), and bone formation on micro-CT (172.9 mm3 vs. 126.7 mm3 for controls) (p<.01). The high-dose zinc also demonstrated a significantly higher radiographic score (p=.017) and bone formation on micro-CT (172.7 mm3 vs. 126.7 mm3) (p<.01) versus controls, and was trending toward higher manual palpation scores (p=.058). ConclusionsThis study demonstrates the potential benefit of a locally applied insulin-mimetic agent, such as zinc, in a rat lumbar fusion model. Previous studies have demonstrated the benefits of local insulin application in the same model, and it appears that zinc has similar effects.

Metforminium Decavanadate as a Potential Metallopharmaceutical Drug for the Treatment of Diabetes Mellitus.

New potential drugs based on vanadium are being developed as possible treatments for diabetes mellitus (DM) and its complications. In this regard, our working group developed metforminium decavanadate (MetfDeca), a compound with hypoglycemic and hypolipidemic properties. MetfDeca was evaluated in models of type 1 and type 2 diabetes mellitus, on male Wistar rats. Alloxan-induction was employed to produce DM1 model, while a hypercaloric-diet was employed to generate DM2 model. Two-month treatments with 3.7 μg (2.5 μM)/300 g/twice a week for DM2 and 7.18 μg (4.8 μM)/300 g/twice a week for DM1 of MetfDeca, respectively, were administered. The resulting pharmacological data showed nontoxicological effects on liver and kidney. At the same time, MetfDeca showed an improvement of carbohydrates and lipids in tissues and serum. MetfDeca treatment was better than the monotherapies with metformin for DM2 and insulin for DM1. Additionally, MetfDeca showed a protective effect on pancreatic beta cells of DM1 rats, suggesting a possible regeneration of these cells, since they recovered their insulin levels. Therefore, MetfDeca could be considered not only as an insulin-mimetic agent, but also as an insulin-enhancing agent. Efforts to elucidate the mechanism of action of this compound are now in progress.

Structure-specific adipogenic capacity of novel, well-defined ternary Zn(II)-Schiff base materials. Biomolecular correlations in zinc-induced differentiation of 3T3-L1 pre-adipocytes to adipocytes

Among the various roles of zinc discovered to date, its exogenous activity as an insulin mimetic agent stands as a contemporary challenge currently under investigation and a goal to pursue in the form of a metallodrug against type 2 Diabetes Mellitus. Poised to investigate the adipogenic potential of Zn(II) and appropriately configure its coordination sphere into well-defined anti-diabetic forms, (a) a series of new well-defined ternary dinuclear Zn(II)–L (L=Schiff base ligands with a variable number of alcoholic moieties) compounds were synthesized and physicochemically characterized, (b) their cytotoxicity and migration effect(s) in both pre- and mature adipocytes were assessed, (c) their ability to effectively induce cell differentiation of 3T3-L1 pre-adipocytes into mature adipocytes was established, and (d) closely linked molecular targets involving or influenced by the specific Zn(II) forms were perused through molecular biological techniques, cumulatively delineating factors involved in Zn(II)-induced adipogenesis. Collectively, the results (a) reveal the significance of key structural features of Schiff ligands coordinated to Zn(II), thereby influencing its (a)toxicity behavior and insulin-like activity, (b) project molecular targets influenced by the specific forms of Zn(II) formulating its adipogenic potential, and (c) exemplify the interwoven relationship between Zn(II)–L structural speciation and insulin mimetic biological activity, thereby suggesting ways of fine tuning structure-specific zinc-induced adipogenicity in future efficient antidiabetic drugs.

Metal Complexes with Ethylenediaminedicarboxylic Acids and Their Derivatives, Promising Pharmacological and Diagnostic Agents (Review)

The literature on metal complexes with ethylenediaminedicarboxylic acids and their derivatives as promising pharmacological and diagnostic agents was reviewed. Complexes of platinum-group metals are promising anticancer agents. Bactericidal and fungicidal properties were found for several Pt(IV) and Pd(II) complexes. Complexes of Zn(II) and VO(IV) with ethylenediamine-N,N'-dicarboxylic acids were viewed as hypoglycemic (insulin-mimetic) agents. Complexes of radionuclides (99mTc, 111In, 67Ga) were described as diagnostic radiopharmaceuticals.

Cinnamon has Higher Efficacy in Attenuating Postprandial Hyperglycemia in Healthy Subjects When Taken After Intake of Glucose

Cinnamon's potential efficacy in regulating hyperglycemia has been gaining interest. Evidence from animal studies proves its efficacy as an insulin mimetic and insulin-sensitizing agent. Other studies on humans reported that this spice lowers fasting blood glucose after several weeks of consumption. This study investigated the ability of cinnamon to attenuate postprandial hyperglycemia and whether time of ingestion is a determining factor of its efficacy in normal subjects. The study was approved by the university ethical committee. Thirty healthy subjects fasted for 10–12 hours prior to each experiment of the study and each of this experiment has a 1-week washout period. For the control (C) experiment, the subjects were given 75 g of D-(+)-glucose monohydrate alone, whereas for the treatment experiments subjects were given 6 g of cinnamon at different times such as 30 minutes before (B), 30 minutes after (A) ingestion of glucose and simultaneously (S) given with glucose. At 0, 30, 60, 90 and 120 minutes after treatment blood sample was taken then measured its glucose content using Accu-chek Performa®. The total iAUC (±SEM) measured are as follows: C (17,262±351), B (15,592±345), A (13,025±305) and S (14,668±460). One-way ANOVA test was used to compare means of iAUC among the control and treatment groups and the significance of the difference of each pair is C-vs-B (p=.021), C-vs-S (p=.000), C-vs-A (p=.000), B-vs-S (p=.038), B-vs-A (p=.000), S-vs-A (p=.024). It is concluded that cinnamon significantly attenuates postprandial hyperglycemia and it has higher efficacy when taken 30 min after ingestion of glucose.

Hypermetabolic state in the 7-month-old triple transgenic mouse model of Alzheimer's disease and the effect of lipoic acid: a 13C-NMR study.

Alzheimer's disease (AD) is characterized by age-dependent biochemical, metabolic, and physiologic changes. These age-dependent changes ultimately converge to impair cognitive functions. This study was carried out to examine the metabolic changes by probing glucose and tricarboxylic acid cycle metabolism in a 7-month-old triple transgenic mouse model of AD (3xTg-AD). The effect of lipoic acid, an insulin-mimetic agent, was also investigated to examine its ability in modulating age-dependent metabolic changes. Seven-month-old 3xTg-AD mice were given intravenous infusion of [1-(13)C]glucose followed by an ex vivo (13)C nuclear magnetic resonance to determine the concentrations of (13)C-labeled isotopomers of glutamate, glutamine, aspartate, gamma aminobutyric acid, and N-acetylaspartate. An intravenous infusion of [1-(13)C]glucose+[1,2-(13)C]acetate was given for different periods of time to distinguish neuronal and astrocytic metabolism. Enrichments of glutamate, glutamine, and aspartate were calculated after quantifying the total ((12)C+(13)C) concentrations by high-performance liquid chromatography. A hypermetabolic state was clearly evident in 7-month-old 3xTg-AD mice in contrast to the hypometabolic state reported earlier in 13-month-old mice. Hypermetabolism was evidenced by prominent increase of (13)C labeling and enrichment in the 3xTg-AD mice. Lipoic acid feeding to the hypermetabolic 3xTg-AD mice brought the metabolic parameters to the levels of nonTg mice.

Local ZnCl2 accelerates fracture healing

This study evaluated the effect of local zinc chloride (ZnCl2 ), an insulin mimetic agent, upon the early and late parameters of fracture healing in rats using a standard femur fracture model. Mechanical testing, radiographic scoring, histomorphometry, qualitative histological scoring, PCNA immunohistochemistry, and local growth factor analysis were performed. Fractures treated with local ZnCl2 possessed significantly increased mechanical properties compared to controls at 4 weeks post fracture. The radiographic scoring analysis showed increased cortical bridging at 4 weeks in the 1.0 (p=0.0015) and 3.0 (p<0.0001) mg/kg ZnCl2 treated groups. Histomorphometry of the fracture callus at day 7 showed 177% increase (p=0.036) in percent cartilage and 133% increase (p=0.002) in percent mineralized tissue with local ZnCl2 treatment compared to controls. Qualitative histological scoring showed a 2.1× higher value at day 7 in the ZnCl2 treated group compared to control (p = 0.004). Cell proliferation and growth factors, VEGF and IGF-I, within fracture calluses treated with local ZnCl2 were increased at day 7. The results suggest local administration of ZnCl2 increases cell proliferation, causing increased growth factor production which yields improved chondrogenesis and endochondral ossification. Ultimately, these events lead to accelerated fracture healing as early as 4 weeks post fracture.