Antidiabetic activity of Syzygium calophyllifolium in Streptozotocin-Nicotinamide induced Type-2 diabetic rats

Exploring the therapeutic potential of Caralluma fimbriata for antioxidant and diabetes management: a 28-day rat model study

This study evaluated the anti-oxidant and anti-diabetic potential of Caralluma fimbriata (CF) in 28-days rat modelling trial. Diabetes is a chronic disorder characterized by elevated blood glucose levels and insulin resistance and cause microvascular and macrovascular issues. Caralluma fimbriata was evaluated for its nutritional composition along with anti-oxidant potential of CF powder (CFP) and CF extract (CFE) using total phenolic contents (TPC), 2,2-diphenyl-1-picrylhydrazyl (DPPH) and ferric ion reducing antioxidant power (FRAP) assays. Furthermore, anti-diabetic potential was computed by dividing rats into four groups of 5 individuals each. Rats of Group I was non-diabetic and no supplementation was given while rats of group II were diabetic and no supplementation was given. While group III and group IV rats were diabetic and received CFP and CFE supplementation respectively. CF powder's TPC, and DPPH and FRAP activity were observed maximum at 44.17 ± 0.006 (μgFe/g) in water, 68.75 ± 0.49 (μgFe/g) in acetone and 800.81 ± 0.99 (μgFe/g) in hexane. Supplementation of CFP and CFE reduced blood glucose effectively i.e. (125.00 ± 4.04 and 121.00 ± 4.49 mg/dL, respectively). Moreover, the consumption of C. fimbriata can be helpful in the management of diabetes mellitus due to its glucose lowering potential, anorexic effects, anti-oxidant potential and α-amylase inhibition.

Syzygium cumini ameliorates high fat diet induced glucose intolerance, insulin resistance, weight gain, hepatic injury and nephrotoxicity through modulation of PTP1B and PPARγ signaling

Metabolic disorders are majorly associated with insulin resistance and an impaired glucose tolerance. Since, many of the currently available drugs exhibit adverse effects and are resistant to therapies, natural products are a promising alternate in the alleviation of complex metabolic disorders. In the current study, Syzygium cumini methanolic extract (SCE) was investigated for its anti-diabetic and anti-adipogenic potential using C57BL/6 mice fed on high fat diet (HFD). The HFD fed obese mice were treated with 200 mg/kg SCE and compared with positive controls Metformin, Pioglitazone and Sodium Orthovanadate. The biometabolites in SCE were characterized using Fourier transform infrared and gas chromatography and mass spectroscopy. A reduction in blood glucose levels with improved insulin sensitivity and glucose tolerance was observed in SCE-treated HFD obese mice. Histopathological and biochemical investigations showed a reduction in hepatic injury and nephrotoxicity in SCE-administered HFD mice. Results showed inhibition of PTP1B and an upregulation of IRS1 and PKB-mediated signaling in skeletal muscle. A significant decrease in lipid markers such as TC, TG, LDL-c and VLDL-c levels were observed with increased HDL-c in SCE-treated HFD mice. A significant decrease in weight and adiposity was observed in SCE-administered HFD mice in comparison to controls. This decrease could be due to the partial agonism of PPARγ and an increased expression of adiponectin, an insulin sensitizer. Hence, the dual-modulatory effect of SCE, partly due to the presence of 26% Pyrogallol, could be useful in the management of diabetes and its associated maladies.

Neuroprotective effects of terpenoids against streptozotocin-nicotinamide-induced diabetic rats: An in silico, in vitro and in vivo study

The present study focused to determine the neuroprotective effects of terpenoids in streptozotocin & nicotinamide-induced type-2 diabetes in rats. The in silico studies were carried out for 68 terpenoids using AutoDock 4.2. The in vitro cholinestrerase, α-amylase enzyme inhibitory assays were perfomed using standard procedures. For in vivo neuroprotective studies, male wistar rats were separated into five groups and each group comprised of six animals. Treatment groups were received low dose and high dose α-Bisabolol 100 and 200 mg/kg respectively, and the standard groups received rivastigmine 2 mg/kg, p.o. and metformin group 100 mg/kg, p.o. for 30 consecutive days. Administration of streptozotocin (45 mg/kg, i.p.) and nicotinamide (110 mg/kg, i.p.)-induced the type 2 diabetes in all groups except the control. The behavioural assessments such as Morris water maze, and open field test were performed and biochemical parameters such as acetylcholinesterase levels and enzymatic antioxidants and reduced glutathione level were estimated from brain homogenates. Treatment of diabetic rats with α-Bisabolol was lowered blood glucose level, improved spatial recognition memory in behavioural assessments in a concentration dependent manner. It can be concluded that α-Bisabolol could act as a potential drug candidate in the management of diabetic Alzheimer's disease.

"Ficus johannis Boiss. leaves ethanolic extract ameliorate streptozotocin-induced diabetes in rats by upregulating the expressions of GCK, GLUT4, and IGF and downregulating G6P"

The leaves of Ficus johannis Boiss (F. johannis), commonly known as Fig tree, Anjir, and Teen, are used by the folk medicinal practitioners in Iran for controlling hyperglycemia in diabetic patients. This study investigated the pharmacological basis for antidiabetic effect of the ethanolic extract of F. johannis leaves using in vitro and in vivo experimental models. Qualitative screening of phytochemicals, estimation of total phenolic and flavonoid contents, and in vitro antioxidant and α-amylase inhibition assays were performed. Moreover, the High-performance liquid chromatography (HPLC) quantification, acute toxicity, glucose tolerance, and in vivo antidiabetic effect along with the evaluation of gene expressions involved in diabetes mellitus were carried out. Significant quantities of phenolic (71.208 ± 2.89 mgg^-1 GAE) and flavonoid (26.38 ± 3.53 mgg^-1 QE) were present. Inhibitory concentration (IC₅₀) of the plant extract exhibited an excellent in vitro antioxidant (IC₅₀ = 33.81 µg/mL) and α-amylase (IC₅₀ = 12.18 µg/mL) inhibitory potential. The HPLC analysis confirmed the gallic acid (257.79 mgg^-1) as main constituent of the extract followed by kaempferol (22.86 mgg^-1), myricetin (0.16 mgg^-1), and quercetin (3.22 mgg^-1). Ethanolic extract displayed glucose tolerance in normo-glycemic rats. Streptozotocin-induced hyperglycemia declined dose dependently in the extract treated rats with improvement in lipid profile and liver and renal function biomarkers. The F. johannis-treated groups showed an increase in mRNA expressions of glucose transporter 4 (GLUT-4), glucokinase, insulin growth like factor 1 and peroxisomal proliferator activating receptor gamma in pancreas. However, the Glucose-6-phosphatase was downregulated. Present study suggests that the ethanolic extract of F. johannis leaves demonstrates a good anti-diabetic profile by improving insulin sensitivity, GLUT-4 translocation, and carbohydrate metabolism while inhibiting lipogenesis.

Amelioration of hyperglycaemia and modulation of pro-inflammatory cytokines by Tamarix gallica fractions in alloxan induced diabetic rats

Present study is engrossed in identification of phyto-constituents from aerial part extracts of Tamarix gallica and appraisal of its anti-oxidant, anti-diabetic and anti-inflammatory potential based upon its folktale use. The methanol and n-hexane fractions of aerial parts were analysed using high performance liquid chromatography (HPLC) and gas chromatography-mass spectrometry (GC-MS) respectively. Inhibitory concentration (IC₅₀) showed better results in case of methanolic extract for both in antioxidant (IC₅₀= 15.47 µg/mL) and alpha amylase (IC₅₀=18.75 µg/mL) assays. Significantly higher quantities of phenolic and flavonoid contents were present in methanolic extract. A significant correlation was found to be existed between these contents and IC₅₀ of antioxidant assay. Alloxan induced hyperglycaemia declined along with improvement in lipid profile, C-reactive proteins (CRP), liver function tests (LFTs) and renal function tests (RFTs). Methanolic fraction (500 mg/kg) was also related to significant reduction in levels of inflammatory markers i.e. tumour necrosis factor-alpha, TNF- α (1.28 ± 0.13 g/L) and interleukin-6, IL-6 (98 ± 10.4 pg/L) as observed in diabetic rats. Based upon the above findings, the study suggests that methanolic fraction from aerial parts of the T. gallica has better anti-diabetic profile which might be attributed to its alpha amylase, anti-oxidant and anti-inflammatory potential.

The Nicotinamide/Streptozotocin Rodent Model of Type 2 Diabetes: Renal Pathophysiology and Redox Imbalance Features

Diabetic nephropathy (DN) is a common complication of diabetes mellitus. While there has been a great advance in our understanding of the pathogenesis of DN, no effective managements of this chronic kidney disease are currently available. Therefore, continuing to elucidate the underlying biochemical and molecular mechanisms of DN remains a constant need. In this regard, animal models of diabetes are indispensable tools. This review article highlights a widely used rodent model of non-obese type 2 diabetes induced by nicotinamide (NA) and streptozotocin (STZ). The mechanism underlying diabetes induction by combining the two chemicals involves blunting the toxic effect of STZ by NA so that only a percentage of β cells are destroyed and the remaining viable β cells can still respond to glucose stimulation. This NA-STZ animal model, as a platform for the testing of numerous antidiabetic and renoprotective materials, is also discussed. In comparison with other type 2 diabetic animal models, such as high-fat-diet/STZ models and genetically engineered rodent models, the NA-STZ model is non-obese and is less time-consuming and less expensive to create. Given that this unique model mimics certain pathological features of human DN, this model should continue to find its applications in the field of diabetes research.

Traditional uses, pharmacological activities, and phytochemical constituents of the genus Syzygium: A review

The genus Syzygium comprises 1200–1800 species that belong to the family of Myrtaceae. Moreover, plants that are belonged to this genus are being used in the traditional system of medicine in Asian countries, especially in China, India, and Bangladesh. The aim of this review is to describe the scientific works and to provide organized information on the available traditional uses, phytochemical constituents, and pharmacological activities of mostly available species of the genus Syzygium in Bangladesh. The information related to genus Syzygium was analytically composed from the scientific databases, including PubMed, Google Scholar, Science Direct, Web of Science, Wiley Online Library, Springer, Research Gate link, published books, and conference proceedings. Bioactive compounds such as flavanone derivatives, ellagic acid derivatives and other polyphenolics, and terpenoids are reported from several species of the genus Syzygium. However, many members of the species of the genus Syzygium need further comprehensive studies regarding phytochemical constituents and mechanism‐based pharmacological activities.

Blood Metabolomics Analysis Identifies Differential Serum Metabolites in Elite and Sub-elite Swimmers

Objective: Metabolites in body fluids, such as lactate, glucose, and creatinine, have been measured by conventional methods to evaluate physical function and performance or athletic status. The objectives of the current study were to explore the novel metabolite biomarkers in professional swimmers with different competition levels using nuclear magnetic resonance (NMR) metabolomics, and try to establish a model to identify the athletic status or predict the competitive potential.

Methods: Serum samples were collected from 103 elite and 84 sub-elite level Chinese professional swimmers, and were profiled by NMR analysis.

Results: Out of the thirty-six serum metabolites profiled, ten were associated with the athletic status of swimmers (with p < 0.05). When compared with sub-elite swimmers, elite swimmers had higher levels of high-density lipoprotein (HDL), unsaturated fatty acid, lactic acid, and methanol. Elite swimmers had lower levels of isoleucine, 3-hydroxybutyric acid, acetoacetate, glutamine, glycine, and α-glucose. A model with four metabolites, including HDL, glutamine, methanol, and α-glucose, was established to predict athletic status by adjusting with different covariates. The area under the curve (AUC) of the best model was 0.904 (95% CI: 0.862-0.947), with a sensitivity and specificity of 75.5 and 90.2%, respectively.

Conclusion: We have identified ten metabolite biomarkers with differentially expressed levels between elite and sub-elite swimmers, the differences could result from genetic or sports level between the two cohorts. A model with four metabolites has successfully differentiated professional swimmers with different competitive levels.

α-Glucosidase Inhibitory and Antimicrobial Benzoylphloroglucinols from Garcinia schomburgakiana Fruits: In Vitro and In Silico Studies

α-Glucosidase plays a role in hydrolyzing complex carbohydrates into glucose, which is easily absorbed, causing postprandial hyperglycemia. Inhibition of α-glucosidase is therefore an ideal approach to preventing this condition. A novel polyprenylated benzoylphloroglucinol, which we named schomburgkianone I (1), was isolated from the fruit of Garcinia schomburgkiana, along with an already-reported compound, guttiferone K (2). The structures of the two compounds were determined using NMR and HRESIMS analysis, and comparisons were made with previous studies. Compounds 1 and 2 exhibited potent α-glucosidase inhibition (IC_50s of 21.2 and 34.8 µM, respectively), outperforming the acarbose positive control. Compound 1 produced wide zones of inhibition against Staphylococcus aureus and Enterococcus faecium (of 21 and 20 mm, respectively), compared with the 19 and 20 mm zones of compound 2, at a concentration of 50 µg/mL. The MIC value of compound 1 against S. aureus was 13.32 µM. An in silico molecular docking model suggested that both compounds are potent inhibitors of enzyme α-glucosidase and are therefore leading candidates as therapies for diabetes mellitus.

Hypoglycemic and Hypolipidemic Effects of Malonyl Ginsenosides from American Ginseng (Panax quinquefolius L.) on Type 2 Diabetic Mice

American ginseng (Panax quinquefolius L.) is popularly consumed as traditional herbal medicine and health food for the treatment of type 2 diabetes mellitus (T2DM). Malonyl ginsenosides (MGR) are the main natural ginsenosides in American ginseng. However, whether the malonyl ginsenosides in P. quinquefolius (PQ-MGR) possess antidiabetic effects has not been explored yet. In this study, the antidiabetic effects and the underlying mechanism of PQ-MGR in high-fat diet/streptozotocin (HFD/STZ)-induced T2DM mice were investigated. The chemical composition was analyzed by high-performance liquid chromatography-electrospray ionization tandem mass spectrometry (HPLC-ESI-MS/MS). Our results showed that 14 malonyl ginsenosides were identified in the PQ-MGR. Among them, the content of m-Rb₁ represented about 77.4% of the total malonyl ginsenosides. After a 5-week experiment, the PQ-MGR significantly reduced the fasting blood glucose (FBG), triglyceride (TG), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), nonesterified fatty acid (NEFA), alanine transaminase (ALT), and aspartate transaminase (AST) levels and improved glucose tolerance and insulin resistance. Furthermore, Western blot analysis demonstrated that the protein expressions of p-PI3K, p-AKT, p-AMPK, p-ACC, PPAR_γ, and GLUT4 in the liver and skeletal muscle were significantly upregulated after PQ-MGR treatment. In contrast, the protein expressions of p-IRS1 and p-JNK were significantly downregulated. Our results revealed that PQ-MGR could ameliorate glucose and lipid metabolism and insulin resistance in T2DM via regulation of the insulin receptor substrate-1/phosphoinositide3-kinase/protein-kinase B (IRS1/PI3K/Akt) and AMP-activated protein kinase/acetyl-CoA carboxylase (AMPK/ACC) pathways. These findings suggest that PQ-MGR may be used as an antidiabetic candidate drug for T2DM treatment.

Identification of Highly Potent α-Glucosidase Inhibitors from Artocarpus integer and Molecular Docking Studies

A new natural Diels-Alder adduct (3) was isolated from the leaves and stem bark of Artocarpus integer, along with seventeen known compounds (1, 2, and 4-18). Structural elucidation was conducted using NMR and HR-ESI-MS data, and comparisons were made with previous studies. Deoxyartonin I (3) exhibited the most potent α-glucosidase inhibition (IC₅₀ 7.80±0.1 μM), outperforming the acarbose positive control. This was mixed-mode inhibition, as indicated by the intersect in the second quadrant of each respective plot. An in silico molecular docking model and the pharmacokinetic features of 3 suggest that it is a potential inhibitor of enzyme α-glucosidase, and is therefore a lead candidate as a drug against diabetes mellitus.

Effect of co-administration of metformin and extracts of Costus pictus D.Don leaves on alloxan-induced diabetes in rats

Background and aim

The present study evaluates the antidiabetic effects of aqueous (CPAQ) and methanolic (CPME) extract of Costus pictus D. Don singly and/or in combination with metformin in alloxan-induced diabetic rats.

Experimental procedure

CPAQ and CPME (400 mg/kg dose), metformin (120 mg/kg) and two different combinations of plant extracts and metformin (200 + 60 mg/kg and 400 mg/kg + 60 mg/kg) were orally given to alloxan-induced diabetic rats for 21 days. At 0, 7, 14, and 21 days, body weight and blood glucose levels were measured.

Results and conclusion

After 21 days of treatment, biochemical profiling and histopathology analysis were carried out. CPAQ and CPME, when administrated separately, could decrease blood glucose levels (P ≤ 0.05). CPME showed more promising results (P ≤ 0.05) compared to the diabetic control group. Extracts co-administrated with metformin showed dose-dependent significant recovery of hypoglycemic activity of metformin. Fasting blood glucose levels, body weight, protein, and lipid profile of the treatment group were compared to the diabetic and normal control groups. Animal groups co-administered with CPME and metformin showed more significant effects on the recovery of tissue damages. The synergistic effect of plant extracts with metformin has positive effects on all the parameters and enhanced the efficiency and reduction of blood glucose levels.

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Costus pictus D. Don. Leaves used traditionally in mulching also treats diabetes.

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Methanolic extract of the plant has potent antihyperglycaemic activity compared to aqueous extract.

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Simultaneous oral administration of the C. pictus methanolic extract with metformin positively affected the blood-glucose-lowering activity.

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There was a synergistic effect between standard drugs, Metformin and CPAQ and CPME.

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C. pictus and metformin have a great influence on the recovery of damaged tissues of the experimental animals.

GC-MS analysis and molecular docking of bioactive compounds of Camellia sinensis and Camellia assamica

The methanol extract of Camellia sinensis (MES) and acetone extract of Camellia assamica (AEA) were subjected to the thin layer chromatography to separate the bioactive compounds. The antimicrobial activity of all the fractions was carried out against pathogenic microorganisms by the agar-well diffusion method. The most effective bioactive fraction of each plant species was analysed by GC-MS. Fraction L of methanol extract of C. sinensis (MES) and fraction 5 of acetone extract of C. assamica (AEA) were found very effective against selected pathogenic strains. GC-MS analysis of this fraction showed the presence of n-heptadecanol-1 (68.63%) in MES and 2',6'dihydroxyacetophenone, bis(trimethylsilyl) (17.58%) in AEA with the highest area. The compounds n-heptadecanol-1 and 2',6'dihydroxyacetophenone, bis(trimethylsilyl) ether were used for docking to analyse its therapeutic potential. The ligand compound n-heptadecanol-1 (HEP) from MES of C. sinensis and 2',6'dihydroxyacetophenone, bis(trimethylsilyl) ether from AEA of C. assamica were docked with the target protein dihydropteoate synthase (DHPS) active sites of Escherichia coli and Staphylococcus aureus active sites via Auto Dock Vina, thereby forecasting the finest binding position of ligands. AutoDock Vina docked results revealed the involvement of binding energy for the establishment of the protein-ligand structure complex, besides generating an interpretation of all apparent molecular interactions accountable for its activity. Further, the protein-ligand complex of MES, EcDHPS + HEP and SaDHPS + HEP exhibiting the best binding affinity were - 4.8 kcal/mol and - 3.6 kcal/mol. The protein-ligand complex of AEA, i.e., EcDHPS + DHA and SaDHPS + DHA exhibited the best binding affinity of - 4.8 kcal/mol and - 4.8 kcal/mol.

Herbal Medicines for Diabetes Management and its Secondary Complications

Diabetic Mellitus (DM) is a metabolic disorder that is concerning for people all over the world. DM is caused due to lack of insulin or ineffective production of insulin in the pancreas. A total of 463 million people were reported to have diabetes mellitus in 2019 and this number is predicted to rise up to 578 million by the year 2030 and 700 million by 2045. High blood sugar gives rise to many complications like diabetic retinopathy, diabetic nephropathy, atherosclerosis, hypercoagulability, cardiovascular disease, coronary heart disease, abdominal obesity, hypertension, hyperlipidemia, cerebrovascular disease, coronary artery disease, foot damage, skin complications, Alzheimer's disease, hearing impairment, and depression. These life-threatening complications make diabetes more severe than other diseases. Many synthetic drugs have been developed, but still, a complete cure is not provided by any of the molecules. Continuous use of some synthetic agents causes severe side effects, and thus the demand for non-toxic, affordable drugs still persists. Traditional treatments have been an extremely valued source of medicine all over human history. These are extensively used throughout the world, indicating that herbs are a growing part of modern and high-tech medicines. The World Health Organization (WHO) has listed a total of 21,000 plants, which are used for medicinal purposes around the world. Among them, more than 400 plants are available for the treatment of diabetes. Despite the fact that there are many herbal drugs available for treating diabetes, only a small number of these plants have undergone scientific and medical evaluation to assess their efficacy. Trigonella foenum-graecum, Allium sativum, Caesalpinia bonduc, Ferula assafoetida,etc., are some of the medicinal plants used for antidiabetic therapy. The presence of phenolic compounds, flavonoids, terpenoids, and coumarins is responsible for the antidiabetic nature of the medicinal plants. These constituents have shown a reduction in blood glucose levels. Pycnogenol, acarbose, miglitol, and voglibose are some of the examples of marketed drugs, which are obtained from natural origin and used as antidiabetic drugs. The active principles derived from the plants work through many antidiabetic mechanisms, which include inhibition of α-glucosidase, α-amylase, and protein tyrosine phosphatase 1B activities. One of the major advantages of herbal drugs is the low level of side effects attributed to these medicines, and this attracted various researchers to develop new molecules for the treatment of diabetes. In this review, recent advances in the field of herbal drugs to treat diabetes, prevent secondary complications from arising due to diabetes, and various herbal molecules in different stages of clinical trials will be emphasized upon.

Curative Effect of Catechin Isolated from Elaeagnus Umbellata Thunb. Berries for Diabetes and Related Complications in Streptozotocin-Induced Diabetic Rats Model

In this study, catechin (CTN) isolated from Elaeagnus umbellata was evaluated for in vitro antioxidant potential and inhibition of carbohydrate digestive enzymes (α-amylase and α-glucosidase). The compound was also tested for its in vivo antidiabetic potential using Sprague-Dawley rats as experimental animals. The effects of various doses of catechin in STZ (Streptozotocin) induced diabetic rats on fasting blood glucose level, body weight, lipid parameters, hepatic enzymes, and renal functions were evaluated using the reported protocols. The CTN exhibited the highest percent antioxidant for free radical scavenging activity against DPPH and ABTS free radicals, and inhibited the activity of carbohydrate digestive enzymes (with percent inhibition values: 79 ± 1.5% α-amylase and 80 ± 1.1% α-glucosidase). Administration CTN and standard glibenclamide significantly decreased the fasting blood glucose level and increased the body weight in STZ-induced diabetic rats. CTN significantly decreased the different lipid parameters, hepatic, and renal function enzyme levels along with Hb1c level in diabetic rats, while significantly increasing the high-density lipoprotein (HDL) level with values comparable to the standard glibenclamide. Further, the altered levels of glutathione and lipid peroxides of liver and kidney tissues were restored (by CTN) to levels similar to the control group. CTN significantly increased the antioxidant enzyme activities, total content of reduced glutathione, and reduced the malondialdehyde (MDA) level in rat liver and kidney tissues homogenates, and also corrected the histopathological abnormalities, suggesting its antioxidant potential.

Therapeutic Effects of Morinda citrifolia Linn. (Noni) Aqueous Fruit Extract on the Glucose and Lipid Metabolism in High-Fat/High-Fructose-Fed Swiss Mice

The aim of this study was to evaluate the therapeutic effects of two different doses (250 and 500 mg/kg) of Morinda citrifolia fruit aqueous extract (AE) in high-fat/high-fructose-fed Swiss mice. The food intake, body weight, serum biochemical, oral glucose tolerance test (OGTT), and enzyme-linked immunosorbent assay (ELISA), as well as histological analyses of the liver, pancreatic, and epididymal adipose tissue, were used to determine the biochemical and histological parameters. The chemical profile of the extract was determined by ultra-fast liquid chromatography–diode array detector–tandem mass spectrometry (UFLC–DAD–MS), and quantitative real-time PCR (qRT-PCR) was used to evaluate the gene expressions involved in the lipid and glucose metabolism, such as peroxisome proliferative-activated receptors-γ (PPAR-γ), -α (PPAR-α), fatty acid synthase (FAS), glucose-6-phosphatase (G6P), sterol regulatory binding protein-1c (SREBP-1c), carbohydrate-responsive element-binding protein (ChREBP), and fetuin-A. Seventeen compounds were tentatively identified, including iridoids, noniosides, and the flavonoid rutin. The higher dose of AE (AE 500 mg/kg) was demonstrated to improve the glucose tolerance; however, both doses did not have effects on the other metabolic and histological parameters. AE at 500 mg/kg downregulated the PPAR-γ, SREBP-1c, and fetuin-A mRNA in the liver and upregulated the PPAR-α mRNA in white adipose tissue, suggesting that the hypoglycemic effects could be associated with the expression of genes involved in de novo lipogenesis.

Hypoglycemic and Antihyperglycemic Activities of 80% Methanol Root Extract of Acanthus polystachyus Delile (Acanthaceae) in Type 2 Diabetic Rats

Background

The morbidity and mortality rate from diabetic mellitus are increasing in the world especially in low- and middle-income countries; hence, it is necessary to evaluate the efficacy and safety of medicinal plants to support existing drugs in treating diabetes mellitus. Therefore, the aim of this study was to evaluate the hypoglycemic effect of 80% methanol root extract of Acanthus polystachyus in normoglycemic, hyperglycemic, and streptozotocin–nicotinamide induced diabetic rats.

Methods

Male albino Wistar rats were divided into five groups (n=6) in all three models. In all models, group one rats served as a negative control and were received vehicle (10mL/kg distilled water), whereas group two (APRE100), three (APRE200), and four (APRE400) were treated with 100, 200, and 400mg/kg of extract, respectively, and group five were treated with glibenclamide (5mg/kg) and served as a positive control. Blood glucose levels were measured at different time points by taking blood from their tails. Data were analyzed using one-way ANOVA followed by Tukey’s post hoc test to carry out comparisons between and within-group and P < 0.05 was considered as statistically significant.

Results

The root of Acanthus polystachyus reduces peak blood sugar levels significantly after the loading of oral glucose at all tested doses. In streptozotocin–nicotinamide-induced type 2 diabetic rats, the daily oral administration of the crude extracts showed a significant reduction of blood glucose level at all tested doses compared to the negative control group. However, the extract did not reduce blood glucose levels in normoglycemic rats at all tested doses compared to both negative and positive control.

Conclusion

From this study, it can be concluded that the root extract of Acanthus polystachyus showed an antihyperglycemic effect in hyperglycemic and diabetic rats but lack hypoglycemic effect in normoglycemic rats. Hence, the plant root may be a good candidate for the development of new antidiabetic drugs.

Delonix regia a Folklore Remedy for Diabetes; Attenuates Oxidative Stress and Modulates Type II Diabetes Mellitus

BACKGROUND

The folkloric profile of Delonix regia demonstrates that it can be used in the management of diabetes.

OBJECTIVE

The present study was conducted to evaluate the safety profile of the aerial part extracts of Delonix regia and their antidiabetic potential along with improvement in oxidative stress.

MATERIALS AND METHODS

Phytochemical screening, total phenolic, and flavonoid contents along with in-vitro antioxidant and alpha-amylase inhibitory activities were determined. HPLC analysis, acute toxicity, glucose tolerance, in-vivo antidiabetic effect along with the influence on biochemical, oxidative stress parameters, and comet assay of the active extract were performed and assessed.

RESULTS

Total phenolic (831.6±0.002 mg/g GAE) and flavonoid (361.4±0.002 mg/g QE) contents were found to be higher in the methanolic extract. Inhibitory concentration IC50 indicated better results for the methanolic extract in DPPH (47.6μg/mL) and alpha-amylase inhibitory (14.61μg/mL) assays. HPLC analysis of the methanolic extract confirmed the presence of quercetin, gallic acid, caffeic acid, cinnamic acid, ferulic acid, and p-coumaric acid. Acute oral toxicity exhibited no mortality and morbidity during the 24h period. The methanolic extract showed better tolerance to glucose. Streptozotocin- nicotinamide (55-110 mg/kg) induced hyperglycemia declined along with improvement in hematological, biochemical parameters and oxidative stress markers (SOD, CAT, H202) in a dose-dependent manner. The maximum effect was recorded at 500mg/kg dose. Comet assay was performed for genotoxic studies and it was observed that the methanolic extract of Delonix regia showed the maximum genoprotective effect at 100μg/mL.

CONCLUSION

The findings suggest that the methanolic aerial part extract of Delonix regia exhibited hypoglycemic, antioxidant, and hypolipidemic activities. The antidiabetic effect was comparable to glibenclamide suggesting its therapeutic use as a natural anti-diabetic remedy.

Caryocar brasiliense Cambess. Pulp Oil Supplementation Reduces Total Cholesterol, LDL-c, and Non-HDL-c in Animals

The fruit of Caryocar brasiliense Cambess. is a source of oil with active compounds that are protective to the organism. In our work, we analyzed the physicochemical characteristics and evaluated the effects of supplementation with C. brasiliense oil in an animal model. We characterized the oil by indices of quality and identity, optical techniques of absorption spectroscopy in the UV–Vis region and fluorescence, and thermogravimetry/derived thermogravimetry (TG/DTG). For the animal experiment, we utilized mice (Mus musculus) supplemented with lipidic source in different dosages. The results demonstrated that C. brasiliense oil is an alternative source for human consumption and presents excellent oxidative stability. Primarily, it exhibited oleic MFA (53.56%) and palmitic SFA (37.78%). The oil level of tocopherols and tocotrienols was superior to the carotenoids. The supplementation with C. brasiliense oil reduced the levels of total cholesterol, LDL-c, and non-HDL-c. Regarding visceral fats and adiposity index, the treatment synergically supplemented with olive oil and C. brasiliense oil (OO + CO) obtained the best result. Therefore, C. brasiliense oil is a high quality product for consumption. Its supplementation promotes beneficial effects mainly on the lipidic profile.

Effect of Supplementation with Hydroethanolic Extract of Campomanesia xanthocarpa (Berg.) Leaves and Two Isolated Substances from the Extract on Metabolic Parameters of Mice Fed a High-Fat Diet

There are still controversies regarding the correlation between the beneficial effects for health and the administration of isolated compounds or crude extracts in therapeutic applications. Campomanesia xanthocarpa, found in the Brazilian Cerrado, demonstrated beneficial effects in metabolic disorders associated with obesity. We investigated the effects of Campomanesia xanthocarpa hydroethanolic extract and two isolated substances from the extract (S1 and S2) in a diet-induced obesity (DIO) model. Male Swiss mice were divided into five groups: (1) American Institute of Nutrition (AIN-93M) diet, (2) high-fat diet (HF), (3) HF supplemented with C. xanthocarpa hydroethanolic leaf extract at 100 mg/kg (HFE), (4) HF supplemented with S1 at 1 mg/kg (HFS1) and (5) HF supplemented with S2 at 1 mg/kg (HFS2). The HFS1, HFS2 and HFE groups did not present decreasing body weight or visceral adiposity gain. No differences in glycemic and lipid parameters, or in the expression of protein content in two cytokines, interleukin-6 (IL-6) and anti-inflammatory (IL-10), were observed. Only the HFS1 group displayed decreased food intake. Even though substantial effects such as an improvement in obesity features or the metabolic and histological parameters promoted by S1, S2 and the extract were not observed, further investigations are necessary to evaluate the principal genes and protein expressions involved in regulating food behavior promoted by S1.

Catharanthus roseus Combined with Ursolic Acid Attenuates Streptozotocin-Induced Diabetes through Insulin Secretion and Glycogen Storage

Catharanthus roseus (C. roseus) and ursolic acid (UA) are ayurvedic medicines with multiple pharmacological activities including antidiabetic activity, but till date, no study is available on their combination. This study documented the antidiabetic efficacy of the combination of C. roseus and UA in rats. Rats were divided into six groups. All groups were given a single dose of Streptozotocin (STZ) at a dose of 50 mg/kg by intraperitoneal route for induction of diabetes, except the normal control group. Group 1 was treated as a normal control (NC) group and fed with saline water, Group 2 as a Diabetes Control group, Group 3 as a STZ+C. roseus ethanolic extract (CREE) group at 50 mg/kg p.o., Group 4 as a STZ+UA group orally at 50 mg/kg, Group 5 as a STZ+CREE (25 mg/kg p.o.)+UA (25 mg/kg p.o.) group, and Group 6 as a STZ+Glimepiride (0.1 mg/kg) group. Diabetes was confirmed after 72 hours by estimation of blood glucose level, and then treatment was given for the next 28 days. During the course of treatment, plasma insulin and blood glucose were measured regularly at the interval of 7 days. At the end of the protocol, blood was collected and animals were sacrificed. The glucose level, insulin level, liver glycogen storage level, and antioxidant enzymes (LPO, CAT, SOD, GPx, GST) were measured. The blood glucose level in Group 5 significantly (P < 0.001) reduced to 98.35 ± 2.45 mg/dl in comparison with that in Group 2 (321.75 ± 5.46 mg/dl). The level of plasma insulin in Group 5 increased (13.65 ± 0.10 μU/ml) significantly (P < 0.01) as compared with that in Group 2 (05.93 ± 0.31 μU/ml). In Group 5, the level of glycogen in liver was significantly (P < 0.01) increased as compared with that in Group 2 rats. The level of antioxidant enzymes in Group 5 restored toward normal values significantly (P < 0.01; P < 0.001) as compared with that in Group 2 animals. These findings suggest that low-dose combination of CREE and UA is effective in the treatment of diabetes.

Phosphocreatine Improves Cardiac Dysfunction by Normalizing Mitochondrial Respiratory Function through JAK2/STAT3 Signaling Pathway In Vivo and In Vitro

Diabetic cardiomyopathy (DCM) is one of the common cardiovascular complications in patients with diabetes. Accumulating evidence has demonstrated that DCM is thoroughly related to mitochondrial energy impairment and increases the generation of reactive oxygen species (ROS). Therefore, an ongoing study is developing strategies to protect cardiac mitochondria from diabetic complications, especially from hyperglycemia. Phosphocreatine (PCr) plays a major metabolic role in cardiac muscular cells including intracellular concentration of ATP which affects the activity of the myocardium. We hypothesized that PCr might improve oxidative phosphorylation and electron transport capacity in mitochondria impaired by hyperglycemia in vivo and in vitro. Also, we aimed to evaluate the protective effect of PCr against DCM through the JAK2/STAT3 signaling pathway. The mitochondrial respiratory capacity from rats and H9C2 cells was measured by high-resolution respirometry (HRR). Expressions of proteins Bax, Bcl-2, caspase 3, caspase 9, cleaved caspase 3, and cleaved caspase 9, as well as JAK2/STAT3 signaling pathways, were determined by western blotting. ROS generation and mitochondrial membrane potential (MMP) were measured with fluorescent probes. Type 1 diabetes mellitus was induced in Wistar male rats by a single intraperitoneal injection of streptozotocin (STZ) (80 mg/kg body weight). Our results revealed that PCr possessed protective effects against DCM injury by improving the mitochondrial bioenergetics and by positively exerting protective effects against DCM in vivo and in vitro, not only improving diabetes symptom, resulting in changes of cardiac tissue using hematoxylin and eosin (H&E) stain, but also ameliorating biochemical changes. Moreover, PCr increased Bcl-2, caspase 3, and caspase 9 protein expressions and decreased Bax, cleaved caspase 3, and cleaved caspase 9 expressions as well as the JAK2/STAT3 signaling pathway. In conclusion, PCr improves mitochondrial functions and exerts an antiapoptotic effect in vivo and in vitro exposed to oxidative stress by hyperglycemia through the JAK2/STAT3 signaling pathway. Our findings suggest that PCr medication is a possible therapeutic strategy for cardioprotection.

Effect of olive leaves extract on the antidiabetic effect of glyburide for possible herb-drug interaction

The concomitant use of olive leaves (OL) and glyburide (GLB) is a possible therapy for diabetic patients. However, there is no report about the effect of OL on the antidiabetic effect of GLB till now. In the current study, the possible interaction of olive leaves extract (OLE) with GLB was assessed to determine if there was any pharmacological benefit over GLB alone. Seven groups of male Sprague Dawley rats were used. Normal rats of the 1st group treated with 2 mL/kg of 3% Tween 80 (vehicle). The 2nd–5th groups were diabetic rats received vehicle, GLB (5 mg/kg), OLE low dose and OLE high dose respectively, while the 6th–7th groups administered combinations of GLB plus OLE low dose and GLB plus OLE high dose, respectively. All treatments were administered orally once daily for 8 weeks.

The use of GLB+OLE-500 obviously improved fasting blood glucose (FBG), insulin and glycated hemoglobin (HbA1c) in diabetic rats (95.5 ± 5.55 mg/dL, 6.8 ± 0.16 mg/dL and 6.1 ± 0.29%, respectively) compared to those treated with GLB monotherapy (140.0 ± 6.36 mg/dL, 5.4 ± 0.19 mg/dL and 7.0 ± 0.20%, respectively). The lipid profile [triglycerides (TG), total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C) and low-density lipoprotein cholesterol (LDL-C)] was significantly improved in diabetic rats exposed to GLB+OLE-500 (35.6 ± 1.51 mg/dL, 48.5 ± 2.74 mg/dL, 25.1 ± 1.21 mg/dL and 17.0 ± 0.82 mg/dL, respectively) in comparison with diabetic group exposed to GLB alone (43.2 ± 2.15 mg/dL, 56.8 ± 2.14 mg/dL, 18.6 ± 0.96 mg/dL, 23.0 ± 1.26 mg/dL, respectively). Additionally, the benefit impacts of GLB+OLE-500GLB+OLE-500 therapy on the antioxidant and lipid peroxidation parameters in the pancreatic tissues of diabetic rats were higher than those of GLB monotherapy. Moreover, GLB plus OLE-500 combination had the greatest effect on restoration of the insulin content of Beta (β) cells and reduction of the glucagon and somatostatin of Alpha (α) and Delta (δ) endocrine cells in the pancreatic islets among the different treatment. The current study suggests that OL and GLB combination could cause herb-drug interactions through modulation of insulin receptor (INR), glucose transporter 2 (Slc2a2) and peroxisome proliferator-activated receptor α (PPAR-α) genes expression in the liver of diabetic rats.

Antidiabetic and hypolipidemic efficacy of skin and seed extracts of Momordica cymbalaria on alloxan induced diabetic model in rats

ETHNOPHARMACOLOGICAL RELEVANCE

Momordica cymbalaria, a wild vegetable belongs to the Cucurbitaceae family, has long been used as a food and a remedy for diabetes mellitus in the Asian native medicinal system.

AIM OF THE STUDY

This study aims to evaluate the efficacy of ethanolic extract of skin (EESK) and methanolic extract of seed (MESE) of M. cymbalaria (MC), for their hypoglycemic and hypolipidemic effects in alloxan induced diabetic rats.

MATERIALS AND METHODS

The diabetes induced rats were given skin and seed extracts at doses 250 and 500 mg/kg b.w. p.o. for 28 days. Alloxan monohydrate (120 mg/kg) was used to induce diabetes mellitus. Daily food and water intake were assessed. Blood glucose levels and body weights were measured every 7 days throughout the experiment. Antioxidant assays, different biochemical and glycemic parameters were evaluated. Histopathological studies on pancreas, liver and kidney were also studied.

RESULTS

Treatment of EESK and MESE showed dose significant decrease in fasting blood glucose level (FBG) in experimental diabetic animals with significant reduction in food and water intake and increase in body weight. Findings confirmed the hypoglycemic and hypolipidemic effects of EESK and MESE in the experimental groups. The impaired glucose tolerance and altered activities of the hepatic enzymes such as AST, ALT and ALP levels of diabetic rats were significantly improved by the administration of EESK and MESE. Oral treatment with MC extract for 28 days demonstrated significant protective effects on the lipid profile, biochemical parameters and antioxidant levels. Besides, biochemical findings were supported by histopathological investigations.

CONCLUSION

These results suggest that the treatment with EESK and MESE of MC at a dose of 500 mg/kg b.w. have better protective effects against hyperglycemia, hyperlipidemia and oxidative stress generated during diabetes justifying the use of the plant in traditional systems of medicine.

Use of an Extract of Annona muricata Linn to Prevent High-Fat Diet Induced Metabolic Disorders in C57BL/6 Mice

Annona muricata Linn, commonly known as graviola, is one of the most popular plants used in Brazil for weight loss. The aim of this study is to evaluate the therapeutic effects of three different doses (50 mg/kg, 100 mg/kg, and 150 mg/kg) of aqueous graviola leaf extract (AGE) supplemented by oral gavage, on obese C57BL/6 mice. Food intake, body weight, an oral glucose tolerance test (OGTT), an insulin sensitivity test, quantification of adipose tissue cytokines, weight of fat pads, and serum biochemical and histological analyses of the liver, pancreas, and epididymal adipose tissue were measured. AGE had an anti-inflammatory effect by increasing IL-10 at doses of 50 and 100 mg/kg. Regarding the cholesterol profile, there was a significant decrease in LDL-cholesterol levels in the AGE 150 group, and VLDL-cholesterol and triglycerides in the AGE 100 and 150 groups. There was an increase in HDL cholesterol in the AGE 150 group. The extract was able to reduce the adipocyte area of the epididymal adipose tissue in the AGE 100 and 150 groups. According to the histological analysis of the liver and pancreas, no significant difference was found among the groups. There were no significant effects of AGE on OGTT and serum fasting glucose concentration. However, the extract was effective in improving glucose tolerance in the AGE 150 group.

Effect of Xylocarpus granatum Bark Extract on Amelioration of Hyperglycaemia and Oxidative Stress Associated Complications in STZ-Induced Diabetic Mice

Xylocarpus granatum is a medicinal mangrove plant, traditionally used for the treatment of diarrhoea, cholera, fever, dyslipidaemia, inflammation, etc. The present study was aimed to evaluate the in vitro antidiabetic (α-glucosidase inhibition assay) and antioxidant (ABTS scavenging and metal chelating assay) activities of ethanol, methanol, and aqueous extracts of leaves and barks of X. granatum followed by in vivo antidiabetic and antioxidant evaluation of ethanol bark extracts in streptozotocin- (STZ-) induced diabetic mice. The in vitro evaluation revealed higher α-amylase inhibition and ABTS scavenging activities in ethanol bark extracts of X. granatum (XGEB). Administration of XGEB at 100 and 200 mg/kg BW doses to STZ-induced diabetic mice resulted in significant decrease (P < 0.05) in blood glucose, triglyceride (TG), total cholesterol (TC), serum glutamate oxaloacetate transaminase (SGOT), serum glutamate pyruvate transminase (SGPT), and urea levels in the serum of the extract administered groups as compared to diabetic control group. The levels of SOD, CAT, GPx, GR, and GST in liver along with LPx, SOD, GST, and GR activities in brain tissues were found to be ameliorated in XGEB treated diabetic mice. Histopathological alternations of liver tissues were also found to be restored in XGEB treated diabetic groups. The HPLC fingerprint analysis of XGEB revealed the presence of simple polyphenols, isoflavone, and flavonol-like compounds. The DSC and UV-VIS analysis also confirmed the presence of phenolic compounds in XGEB. The GC-MS analysis of XGEB showed the presence of a number of bioactive compounds. These results demonstrated the beneficial effect of XGEB in controlling hyperglycaemia and ameliorating oxidative stress associated complications associated with diabetes.

Rhinacanthins-rich extract and rhinacanthin C ameliorate oxidative stress and inflammation in streptozotocin-nicotinamide-induced diabetic nephropathy

In this present study, rhinacanthins-rich extract (RRE) and rhinacanthin C (RC) the main bioactive constituent of Rhinacanthus nasutus was investigated for their protective effect against diabetic nephropathy (DN). Diabetes was induced by administering nicotinamide (100 mg/kg, i.p.)/streptozotocin (60 mg/kg, i.p.) and diabetic rats were orally administered with RRE and RC for 4 weeks. RRE and RC significantly reduced the kidney index, renal oxidative stress markers, and pro-inflammatory cytokines. Furthermore, RRE and RC increased renal levels of glutathione, superoxide dismutase, catalase, and attenuated diabetic induced renal damages. In conclusion, RRE and RC confer protective effect against DN through the inhibition of oxidative stress and inflammation and could be a potential medicinal or nutritional supplement for the prevention of DN. PRACTICAL APPLICATIONS: Rhinacanthus nasutus is a medicinal plant that is extensively used in Thai traditional medicine as an antibacterial, antifungal, antidiabetic, and anti-inflammatory agent. The plant is rich in naphthoquinones, which confer it with several excellent bioactivities. The rich extract of the leaves was prepared with three major bioactive components and the extract was evaluated for its renoprotective effect in diabetic rats. The results from this study provides valuable pharmacological information that supports the use of the plant, especially the rich extract in the prevention and treatment of diabetes and diabetic complications.

Phytochemical analysis and antidiabetic potential of Elaeagnus umbellata (Thunb.) in streptozotocin-induced diabetic rats: pharmacological and computational approach

Background

The fruit of Elaeagnus umbellata has high medicinal values and is an excellent source of phytochemicals. This study was aimed to evaluate the antioxidant, enzyme inhibitory and antidiabetic potential of Elaeagnus umbellata.

Methods

The antioxidant potential of the crude extract and subfractions of E. umbellata fruit were determined using DPPH (2, 20-diphenyl-1-picrylhydrazyl) and ABTS (2, 2′-azinobis-3-ethylbenzothiazoline-6-sulfonic acid) assays. The enzyme inhibitory potentials of extracts against α-amylase and α-glucosidase enzymes were also determined. The in vivo anti-hyperglycemic effects of the extract in STZ-induced type 2 diabetes were determined using Sprague Dawley adult rats. HPLC system (Agilent 1260) was used for the identification of bioactive compounds present in extracts. Molecular docking was used to identify and compare the interaction between the compounds (active constituents) and standard inhibitor acarbose with the α-amylase and α-glucosidase active sites.

Results

The chloroform, ethyl acetate, and butanol fractions showed significant antioxidant potential with IC₅₀ values of 40, 45 and 60 μg/mL against DPPH and 57, 70 and 120 μg/mL against ABTS free radicals respectively. The chloroform and ethyl acetate were highly active against α-amylase and α-glucosidase (IC₅₀ values 58 and 200 μg/ml against α-amylase 60 and 140 μg/ml against α-glucosidase. The crude extract, chloroform, and ethyl acetate fractions were more potent in controlling the hyperglycemia in STZ-induced type 2 diabetes in rats and considerable reduction of glucose level was observed compared to the non-treated group. Furthermore, the extracts were also found useful in controlling the secondary complications associated with type 2 diabetes mellitus which was evident from the observed substantial reduction in the blood level of serum glutamate oxaloacetate transaminase, serum glutamate pyruvate transaminase, alkaline phosphatase, total cholesterol, low-density lipoproteins, and triglycerides. The molecular docking approach indicated the favorable inhibitory interaction between the docked compounds and the active sites of the α-amylase and α-glucosidase. All docked compounds occupied the same binding site as occupied by acarbose.

Conclusion

It was concluded that E. umbellata can be used in the treatment of type 2 diabetes and oxidative stress. The extracts were also found to be effective in relieving the secondary complications associated with type 2 diabetes.

Graphical abstract

Electronic supplementary material

The online version of this article (10.1186/s12906-018-2381-8) contains supplementary material, which is available to authorized users.

Spondias tuberosa inner bark extract exert antidiabetic effects in streptozotocin-induced diabetic rats

ETHNOPHARMACOLOGICAL RELEVANCE

Diabetes mellitus (DM) is one of the most important medical emergencies of the 21st century. However, commercially available oral drugs with antidiabetic properties have been limited because of potential side effects, such as: hypoglycemia, weight gain, hepatic dysfunction and abdominal discomfort. As well as antidiabetic drugs, many types of medicinal herbal supplements are utilized as alternative treatments for DM and related comorbidities. Spondias tuberosa Arruda (Anacardiaceae), popularly known as "umbu", has been used in traditional medicine to treat a vast range of diseases, including DM, infections, digestive disorders, diarrhea and menstrual abnormalities.

AIM OF THE STUDY

This study evaluated the effect of the hydroethanolic extract of the inner stem bark of Spondias tuberosa (EEStb) in streptozotocin-induced diabetic rats.

MATERIALS AND METHODS

Diabetes was induced in rats by a single injection of STZ (40 mg/kg i.p.). Diabetic rats were treated with 250 mg/kg or 500 mg/kg of the EEStb for 21 days. Water intake, urinary volume, body weight, as well as biochemical parameters, such as cholesterol total (TC), high-density lipoprotein cholesterol (HDL-C), triglycerides (TG), hepatic and muscle glycogen urea, alanine and aspartate aminotransferase, total protein, albumin, and glucose blood levels, were analyzed. We also determined the hepatic antioxidant state, as well as both of insulin and glucose tolerance.

RESULTS

The extract was evaluated by HPLC, and the major components of EESTb were identified (i.e. gallic acid and quercetin). The 500 mg/kg dosage of EEStb significantly decreased fasting blood glucose and post-prandial glucose. The EEStb also reduced urinary volume, food and water intake, as well as decreased body weight gain. Diabetic rats that received EEStb had a lower loss of muscle mass and white adipose tissue. Additionally, EEStb improved the urinary excretion of urea and glucose. The extract significantly decreased triglycerides, total cholesterol and VLDL in diabetic rats. However, no significant effect was observed on the levels of total and HDL cholesterol. EEStb treatment prevented hepatotoxic diabetic-induced, improved GSH:GSSG ratio, SOD and CAT activity as well as reduced nitrite and TBARs levels.

CONCLUSIONS

Our results demonstrate that EEStb has antioxidant and hepatoprotective effects as well as improves insulin sensibility in diabetic rats. This indicates that S. tuberosa could be a potential resource for alternative therapies in the treatment of hyperglycemic conditions. These results also support the use of EEStb in ethnomedicine for the management of diabetes.

In vitro and in vivo antidiabetic activity of isolated fraction of Prosopis cineraria against streptozotocin-induced experimental diabetes: A mechanistic study

A rapidly increasing incidence of Diabetes mellitus throughout the world is a major concern in both developed and developing countries and the drawbacks associated with currently available treatments led to switching researcher's attention towards naturopathy. Since ancient time, herbal plants have been traditionally used for the treatment of diabetes as they consider to be less toxic and free from side effects than synthetic ones. In our previous studies, we had isolated two new compounds (Methyl 5-tridecyloctadec-4-enoate and Nonacosan-8-one), together with three known compounds (Lupeol, β-sitosterol and Stigmasterol) from chloroform fraction of stem bark of P. cineraria (CfPc). The present study aimed to determine the in vivo and in vivo antidiabetic activity of CfPc in streptozotocin induced experimental diabetes and also evaluated their possible mode of action. CfPc was orally administrated to STZ (55 mg/kg b.wt) induced diabetic rats at the doses of 50 and 100 mg/kg b.wt for 21 days. Treatment of CfPc significantly (p < 0.05) lowered the level of blood glucose, glycosylated hemoglobin and also restored body weight, liver glycogen content and serum insulin level in diabetic rats in a dose-dependent manner. A significant (p < 0.05) reduction in serum lipid profile markers and elevation in HDL-C after treatment with CfPc, also signifying the protective effects of CfPc in diabetes-associated complications. In addition, CfPc also promoted a significant inhibition of α-amylase enzyme activity with an IC₅₀ value of 40.29 μg/ml. Results indicate that CfPc possess a potential in vitro and in vivo antidiabetic activity and this effect could be due to multitarget mode of action that includes antihyperglycemic, postprandial hypoglycemic, hypolipidemic and insulin secretory actions. Therefore, it could be used as a safer complementary drug in the management of diabetes and associated complications.

Cytotoxic, analgesic and anti-inflammatory properties of Syzygium calophyllifolium bark

The present study explores the effect of Syzygium calophyllifolium bark methanol (SCBM) extract on pain and inflammation as cancer associated symptoms. The anti-proliferative and cell death-inducing ability of the extract was analysed using MCF-7 breast cancer cells. ATP and LDH levels, along with the cell morphology were noted. The anti-proliferative ability of the extract was examined in relation to pain and inflammation. Analgesic activity was determined using a hot plate, acetic acid and formalin-induced pain models in mice. Acute anti-inflammatory activity was observed in carrageenan and egg albumin induced paw oedema in Wistar rats. Chronic inflammation was induced by placing a cotton pellet under the skin at the axial region of rats. Reduced ATP and increased LDH content indicated the cytotoxic effect of the extract. SCBM at 200 mg/kg dose depicted good activity in acetic acid (77.69%) and formalin (80.81%) induced pain models compared to the standard drug indomethacin. However, only a moderate activity was observed in the hot plate method (53.85%). The higher dose of SCBM was equally effective in anti-inflammatory models. The dose (200 mg/kg) significantly reduced the paw oedema in carrageenan (96.71%) and egg albumin models (54.24%) compared to the control. The chronic inflammation was also inhibited upto 70.46% by SCBM. These activities can be attributed to the phenolic compounds detected in HPLC. The outcome of the study states that the extract can reduce both acute and chronic inflammatory conditions and kill the cancer cells, proposing the dual role of SCBM in treating inflammatory pains in cancer. The result of these studies indicated that wild plants like Syzygium calophyllifolium could be taken forward for a detailed study to accomplish the demand for a better treatment against diseases.

Antioxidant SMe1EC2 modulates pentose phosphate pathway and glutathione-dependent enzyme activities in tissues of aged diabetic rats

The pentose phosphate pathway and glutathione-associated metabolism are the main antioxidant cellular defense systems. This study investigated the effects of the powerful antioxidant SMe1EC2 (2-ethoxycarbonyl-8-methoxy-2,3,4,4a,5,9b-hexahydro-1H-pyrido[4,3-b] indolinium dichloride) on pentose phosphate pathway (PPP) and glutathione-dependent enzyme activities in aged diabetic and aged matched control rats. Diabetes was induced by streptozotocin injection in rats aged 13-15 months. Diabetic and control rats were divided into two subgroups, one untreated and one treated with SMe1EC2 (10 mg/kg/day, orally) for 4 months. SMe1EC2 ameliorated body weight loss, but not hyperglycemia of aged diabetic rats. Diabetes resulted in decreased glucose-6-phosphate dehydrogenase (G6PD), 6-phosphogluconate dehydrogenase (6PGD) and glutathione-S-transferase (GST), yet in unchanged glutathione reductase (GR) in the liver of aged diabetic rats. In the liver of the aged control rats, SMe1EC2 did not affect G6PDH, 6PGDH and GR, but it inhibited GST. SMe1EC2 also failed to affect diabetes-induced decline in 6PGDH, it ameliorated G6PDH but produced further decline in GST in the liver of aged diabetic rats. In the kidney of aged rats, G6PDH and GST were found to be comparable among the groups, but diabetes up-regulated 6PGDH and GR; these alterations were prevented by SMe1EC2. In the heart of aged diabetic rats, while GST remained unchanged, the recorded increase in G6PD, 6PGD, GR was prevented by SMe1EC2. Furthermore, an unchanged GR and remarkable increases in G6PD, 6PGD and GST were found in the lung of the aged diabetic group. These alterations were completely prevented by SMe1EC2. The results suggest that in aged rats SMe1EC2 can ameliorate the response of the kidney, heart and lung but not that of the liver against diabetes-induced glucotoxicity by interfering with the activity of redox network enzymes.

Phytochemical composition, antioxidant and anti-bacterial activity of Syzygium calophyllifolium Walp. fruit

Syzygium calophyllifolium fruits are among the important wild edibles used by the tribes of Western Ghats. However, this underutilized fruit remained unnoticed for its medicinal properties. Hence, the present study was undertaken to evaluate the antioxidant activity by DPPH^·, ABTS^·+, FRAP assays and antibacterial efficacy by well diffusion method. GC-MS and HPLC profiles of crude extract and column chromatographic fractions were also determined. The methanolic extract of fruit (MFE) showed high total phenolics, tannins and flavonoids. The faction H (FH) displayed significant antioxidant property in DPPH^· (IC₅₀ 2.1 µg/ml), ABTS^·+ (19483.29 μM Trolox equivalents/g extract) and FRAP (65.5 mM Fe(II)/mg extract) assays over MFE. Moreover, FH also exhibited good antibacterial activity against Escherichia coli (32.0 mm), Salmonella typhi (27.0 mm), Staphylococcus aureus (27.3 mm) at 100 mg/ml concentration. GC-MS revealed 12 major compounds in MFE, HPLC analysis of MFE and FH depicted the presence of rutin and ellagic acid. This study suggested that FH could have high concentration of bioactive compounds like rutin and ellagic acid or its analogues compared to MFE which may be responsible for its strong antioxidant and antibacterial activity.

CB-1R and GLP-1R gene expressions and oxidative stress in the liver of diabetic rats treated with sitagliptin

BACKGROUND

Type 2 diabetes is a major health problem affecting millions of people. Controlled eating and regular physical activity are important for the management of type 2 diabetes. Dipeptidyl peptidase-4 enzyme (DPP-4) inhibitor sitagliptin is a potent agent for the treatment of type-2 diabetes. The aim of this study was to examine the effects of sitagliptin on the liver of rats with streptozotocin (STZ)-induced diabetes, in terms of (i) the expression levels of the cannabinoid 1 receptor (CB-1R) and glucagon-like peptide 1 receptor (GLP-1R), (ii) alterations in the number and localization of these peptides, and (iii) changes in histological and oxidative damage.

METHODS

Thirty-two neonatal (two-day-old) rats, which were divided into four groups, were treated with saline (control), sitagliptin (control; 1.5mg/kg/day for 15 days starting from day 5 of the experimental period), STZ (diabetes; 100mg/kg single dose), STZ+sitagliptin (diabetes+sitagliptin). After 20 days, hepatic tissues were obtained from rats.

RESULTS

The expressions of GLP-1R and CB-1R mRNA increased approximately 1.89- and 2.94-fold, respectively, in the diabetes+sitagliptin group as compared to the diabetic group. Additionally the number of GLP-1R immunopositive cells decreased and CB-1R immunopositive cells increased in comparison to the diabetic group; however, this was not statistically significant. Glutathione levels increased, but malondialdehyde and protein carbonyl levels decreased in the diabetes+sitagliptin group more than the diabetic group.

CONCLUSION

Our findings indicate that sitagliptin treatment regulates GLP-1R and CB-1R gene expressions, which are associated with appetite regulation in diabetic rat, and may decrease oxidative stress and liver tissue damage.

Effects of crude hydroalcoholic extract of Syzygium cumini (L.) Skeels leaves and continuous aerobic training in rats with diabetes induced by a high-fat diet and low doses of streptozotocin

ETHNOPHARMACOLOGICAL RELEVANCE

The leaves of Syzygium cumini (L.) or Skeels (Myrtaceae) are widely used in Brazilian folk medicine to treat diabetes.

AIM OF THE STUDY

The present study evaluated the functional capacity, biochemical parameters, oxidative stress and DNA damage from eight weeks of intervention with a crude hydroalcoholic extract of S. cumini leaves (EBH) and continuous aerobic training (TAC) in diabetic (D) rats.

MATERIALS AND METHODS

A hydroalcoholic (50%) extract was prepared by ultrasound and phytochemical parameters (total phenols, total tannins and myricetin content) were analyzed. Thirty-seven male Wistar rats were divided into five groups: normoglycemic controls (CONT), diabetic controls (D-CONT), diabetics treated with extract (D+EBH), trained diabetic (D+TAC) and diabetics treated with extract and trained (D+EBH+TAC). Functional capacity was assessed with a maximum exercise capacity test; biochemical parameters with enzymatic kits; oxidative stress by superoxide dismutase (SOD), catalase (CAT), thiobarbituric acid reactive substances (TBARS) and oxidized dichlorofluorescein (DCF), and the DNA damage by the comet assay.

RESULTS

The D+TAC and D+EBH+TAC groups showed better functional capacity at the end of interventions. The D+EBH group showed glucose and triglyceride reduction, lowest DNA damage index in the blood, liver, kidney, heart, lung and gastrocnemius muscle, improved SOD levels in the liver, kidney and lung, improved CAT levels in the kidney and lower lipid peroxidation in all tissues studied, compared to the D-CONT group. The exercise (D+TAC) was effective in reducing triglycerides, improving SOD levels in the lung, reducing lipid peroxidation in all tissues studied and reducing the DCF oxidation in the kidney, in addition to protecting against DNA damage in the blood and heart. However, the additive effect of the intervention protocols when combined (EBH+TAC) was observed only in improving the gastrocnemius SOD levels. The phytochemical analyses showed a high content of phenols and the presence of myricetin glycosides.

CONCLUSION

The findings in this study suggest a crude hydroalcoholic extract of S. cumini leaves has potential hypoglycemic, hypolipidemic and protective properties acting against oxidative stress and against DNA damage, probably due to its phenols and myricetin glycoside content and the antioxidant properties of these constituents. Moreover, exercise was suggested to have beneficial effects on diabetes, improving functional capacity, ameliorating blood triglyceride control and decreasing lipid peroxidation, but with no effects on ameliorating blood glucose levels. The association of intervention protocols presented an additive effect on the antioxidant SOD activity in the muscle cells of diabetic rats.