Diosgenin reorganises hyperglycaemia and distorted tissue lipid profile in high-fat diet-streptozotocin-induced diabetic rats

Comprehensive tissue homogenization and metabolite extraction for application in clinical metabolomics

BACKGROUND

Metabolomics and lipidomics analysis of various biological samples offer insights into potential mechanisms of health and disease development. Tissue samples, compared to other biological samples, are less elucidated due to challenges in sample collection and lack of standardized sample preparation protocols for reproducible tissue homogenization and broad-range metabolite extraction.

RESULTS

Pork tissue samples were homogenized with six different solvent mixtures with increasing lipophilicity, followed by metabolites extraction using methanol for polar and methyl-tert-butyl ether (MTBE) in methanol (MeOH) for highly lipophilic compounds. Metabolite profiles of supernatant and homogenate extraction for three extract volumes were compared. Solvent dependent pipette tip blockage was addressed by introduction of a prewetting correction factor for non-polar homogenization solutions and low volume tissue homogenate pipetting. Upset plots were applied for multi-dimensional metabolite extraction efficiency evaluation for 24 different sample preparation conditions. The best-performing homogenization solution was PBS; MeOH (1:1; v/v), combined with a two-step polar metabolite and lipid extraction using MeOH and 75 % MTBE in MeOH employing the tissue homogenate. The optimized experimental conditions were applied on mouse pancreas tissues, providing evidence of varying metabolic pathway activities across different anatomical regions of an organ.

SIGNIFICANCE

This study introduces a comprehensive tissue sample preparation and metabolite quantification workflow, covering highly polar to highly lipophilic metabolites using targeted high performance liquid chromatography electrospray ionization triple quadrupole-linear ion trap mass spectrometer (HPLC-ESI-QTRAP-MS/MS) for absolute quantitation of amino acids, organic acids and keto-acids, acyl-carnitines, and phospho-choline lipids.

Antidiabetic potential of fenugreek (Trigonella foenum-graecum): A magic herb for diabetes mellitus

Fenugreek (Trigonella foenum-graecum) is a widely grown dietary herb in Asia, and its seeds are traditionally used for several diseases, including diabetes. The seeds and leaves possess a variety of compounds that play an important role in regulating their hypoglycemic effect. However, so far, no extensive systematic review exists on its antidiabetic effect, highlighting the molecular mechanisms and isolated compounds. The purpose of this review is to summarize the preclinical and clinical antidiabetic properties of fenugreek and its isolated compounds by focusing on underlying mechanisms. PubMed, Google Scholar, Science Direct, and Scopus databases were searched to retrieve articles until June, 2024. Preclinical studies demonstrated that the antidiabetic effect of fenugreek was mostly associated with enhanced glucose transporter type-4 (GLUT4) translocation and hexokinase activity, decreased glucose-6-phosphatase and fructose-1,6-bisphosphatase activities, inhibited α-amylase and maltase activities, protected β cells, and increased insulin release. Furthermore, few studies have reported its role as a glucagon-like peptide-1 (GLP-1) modulator, 5'-AMP-activated kinase (AMPK) activator, and dipeptidyl peptidase-IV (DPP-IV) inhibitor. Further clinical trials showed that fenugreek seeds improved blood glucose levels, insulin resistance, insulin sensitivity, and lipid profiles. This study highlights significant evidence of the antidiabetic effect of fenugreek and its isolated compounds; therefore, it could be a potential therapy for diabetes.

Study on the components changes of polysaccharides and saponins during nine steaming and drying of Polygonatum sibiricum

BACKGROUND

In this study, the content and structure of Polygonatum sibiricum polysaccharides and saponins during different processing stages were determined.

RESULTS

After processing of Polygonatum, the content of polysaccharide and glucose decreased, and the content of galactose, glucuronic acid and sugar substitution gradually increased. The content of total saponins increased significantly. Only 18 compounds were found in raw Polygonatum and 17 new compounds were presented in processed Polygonatum. During the processing of Polygonatum, the polysaccharide was partially degraded into oligosaccharides, the molecular weight gradually decreased, and the neutral sugar was converted into uronic acid, resulting in a decrease in polysaccharide content. The saponins were partially degraded into sapogenins or modified.

CONCLUSION

This study clarifies the changes in the content and structure of polysaccharides and saponins in processed Polygonatum, which will pave the way for elucidating the processing mechanism. © 2024 Society of Chemical Industry.

Diosgenin as a substitute for cholesterol alleviates NAFLD by affecting CYP7A1 and NPC1L1-related pathway

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) rapidly becomes the leading cause of end-stage liver disease or liver transplantation. Nowadays, there has no approved drug for NAFLD treatment. Diosgenin as the structural analogue of cholesterol attenuates hypercholesterolemia by inhibiting cholesterol metabolism, which is an important pathogenesis in NAFLD progression. However, there has been no few report concerning its effects on NAFLD so far.

METHODS

Using a high-fat diet & 10% fructose-feeding mice, we evaluated the anti-NAFLD effects of diosgenin. Transcriptome sequencing, LC/MS analysis, molecular docking simulation, molecular dynamics simulations and Luci fluorescent reporter gene analysis were used to evaluate pathways related to cholesterol metabolism.

RESULTS

Diosgenin treatment ameliorated hepatic dysfunction and inhibited NAFLD formation including lipid accumulation, inflammation aggregation and fibrosis formation through regulating cholesterol metabolism. For the first time, diosgenin was structurally similar to cholesterol, down-regulated expression of CYP7A1 and regulated cholesterol metabolism in the liver (p < 0.01) and further affecting bile acids like CDCA, CA and TCA in the liver and feces. Besides, diosgenin decreased expression of NPC1L1 and suppressed cholesterol transport (p < 0.05). Molecular docking and molecular dynamics further proved that diosgenin was more strongly bound to CYP7A1. Luci fluorescent reporter gene analysis revealed that diosgenin concentration-dependently inhibited the enzymes activity of CYP7A1.

CONCLUSION

Our findings demonstrated that diosgenin was identified as a specific regulator of cholesterol metabolism, which pave way for the design of novel clinical therapeutic strategies.

Fenugreek derived diosgenin as an emerging source for diabetic therapy

Diabetes is a chronic metabolic disease that endangers the entire body's tissues and organs. Diabetes impairs glucose and insulin regulation in the human body by causing pancreatic cell damage. Diabetes modifies pathways such as serine/threonine protein kinase (Akt) and Protein kinase C (PKC)/- glucose transporter 4 (GLUT4), peroxisome proliferator-activated receptor (PPAR) glucose absorption, and inhibits α-amylase and α-glucosidase, Sodium/glucose cotransporter 1 (SGLT-1), and Na+-K+-ATPase activity. Diabetes may also be caused by a decrease in the expression of sterol regulatory element binding protein 1 (SREBP-1) and its target genes, fatty acid synthase (FAS), stearoyl-CoA desaturase-1 (SCD-1), and acetyl-CoA carboxylase α (ACC), as well as a decrease in the levels of C/EBP homologous protein (CHOP), Caspase12, and Caspase3 proteins. Diabetes has long been linked to diseases of the cardiovascular, nervous, skeletal, reproductive, hepatic, ocular, and renal systems. Diosgenin, a steroidal compound derived from fenugreek, aids in the prevention of diabetes by altering cellular pathways in favor of healthy bodily functions. Diosgenin is a new nutraceutical on the market that claims to cure diabetes in particular. This article focuses on diosgenin extraction and purification, fenugreek bioactive compounds, pharmacological properties of diosgenin, mode of action of diosgenin to cure diabetes, and dosages.

Can Polyherbal Medicine be used for the Treatment of Diabetes? - A Review of Historical Classics, Research Evidence and Current Prevention Programs

Diabetes mellitus (DM), a chronic medical condition, has attained a global pandemic status over the last few decades affecting millions of people. Despite a variety of synthetic drugs available in the market, the use of herbal medicines for managing diabetes is gaining importance because of being comparatively safer. This article reviews the result of a substantial literature search on polyherbal formulations (PHFs) developed and evaluated with potential for DM. The accumulated data in the literature allowed us to enlist 76PHFs consisting of different parts of 147 plant species belonging to 58 botanical families. The documented plant species are laden with bioactive components with anti-diabetic properties and thus draw attention. The most favoured ingredient for PHFs was leaves of Gymnema sylvestre and seeds of Trigonella foenum-graecum used in 27 and 22 formulations, respectively. Apart from herbs, shilajit (exudates from high mountain rocks) formed an important component of 9 PHFs, whereas calcined Mytilus margaritiferus and goat pancreas were used in Dolabi, the most commonly used tablet form of PHF in Indian markets. The healing properties of PHFs against diabetes have been examined in both pre-clinical studies and clinical trials. However, the mechanism(s) of action of PHFs are still unclear and considered the pitfalls inherent in understanding the benefits of PHFs. From the information available based on experimental systems, it could be concluded that plant-derived medicines will have a considerable role to play in the control of diabetes provided the challenges related to their bioavailability, bioefficacy, optimal dose, lack of characterization, ambiguous mechanism of action, and clinical efficiency are addressed.

Glucose increases proliferation and chemoresistance in chronic myeloid leukemia via decreasing antioxidant Properties of ω-3 polyunsaturated fatty acids in the presence of Iron

BACKGROUND

There is a strong association between hyperglycemia, oxidative stress, inflammation and the onset and progression of diabetes which causes a higher risk of cancer. This study investigated, the effect of concomitant use of omega-3 polyunsaturated fatty acids (ω-3 PUFAs) with iron supplements in hyper-glucose conditions on the K-562 cell line.

METHODS

The effects of iron, ω-3 PUFAs, and a combination of both on K-562 cells were investigated under normal and high glucose conditions. The impact of these treatments was evaluated using multiple methodologies, including the MTT assay for cell viability, quantification of oxidative stress markers [total antioxidant capacity (TAC) and malondialdehyde (MDA)], and analysis of the cell cycle. Furthermore, the expression levels of TNFα and p53 mRNA were measured using Real-time PCR.

RESULTS

The co-treatment of ω-3 PUFAs and iron in the presence of high glucose had notable effects, as evidenced by an increase in cell survival, resistance to imatinib chemotherapy, TNFαmRNA expression levels, MDA levels, and percentage of cells in the G2/S phase. Additionally, there was a decrease in the mRNA expression of p53 and TAC levels compared to treatment in the normal-glucose condition.

CONCLUSION

Hyperglycemic conditions in conjunction with the combined treatment of theω-3 PUFAs and iron, led to reduced anticancer capacity, chemosensitivity, anti-inflammatory and antioxidant properties of the K-562 cells. These effects were found to be mediated by oxidative stress.

New insights into anti-diabetes effects and molecular mechanisms of dietary saponins

Diabetes mellitus (DM) is a long-term metabolic disorder that manifests as chronic hyperglycemia and impaired insulin, bringing a heavy load on the global health care system. Considering the inevitable side effects of conventional anti-diabetic drugs, saponins-rich natural products exert promising therapeutic properties to serve as safer and more cost-effective alternatives for DM management. Herein, this review systematically summarized the research progress on the anti-diabetic properties of dietary saponins and their underlying molecular mechanisms in the past 20 years. Dietary saponins possessed the multidirectional anti-diabetic capabilities by concurrent regulation of various signaling pathways, such as IRS-1/PI3K/Akt, AMPK, Nrf2/ARE, NF-κB-NLRP3, SREBP-1c, and PPARγ, in liver, pancreas, gut, and skeletal muscle. However, the industrialization and commercialization of dietary saponin-based drugs are confronted with a significant challenge due to the low bioavailability and lack of the standardization. Hence, in-depth evaluations in pharmacological profile, function-structure interaction, drug-signal pathway interrelation are essential for developing dietary saponins-based anti-diabetic treatments in the future.

Research progress in steroidal saponins from the genus Polygonatum: Chemical components, biosynthetic pathways and pharmacological effects

The genus Polygonatum Mill. belongs to the Liliaceae family, which is widely distributed all over the world. Modern studies have found that Polygonatum plants are very rich in chemical compounds such as saponins, polysaccharides and flavonoids. Steroidal saponins are the most commonly studied saponins in the genus Polygonatum and a total of 156 compounds have been isolated from 10 species of the genus. These molecules possess antitumor, immunoregulatory, anti-inflammatory, antibacterial, antiviral, hypoglycemic, lipid-lowering and anti-osteoporotic activities. In this review, we summarize recent advances in studies of the chemical constituents of steroidal saponins from Polygonatum, including their structural characteristics, possible biosynthetic pathways and pharmacological effects. Then, the relationship between the structure and some physiological activities is considered. This review aims to provide reference for further exploitation and utilization of the genus Polygonatum.

Diosgenin alleviates the inflammatory damage and insulin resistance in high glucose‑induced podocyte cells via the AMPK/SIRT1/NF‑κB signaling pathway

Diabetic nephropathy (DN) is the predominant cause of end-stage renal disease globally. Diosgenin (DSG) has been reported to play a protective role in podocyte injury in DN. The present study aimed to explore the role of DSG in DN, as well as its mechanism of action in a high glucose (HG)-induced in vitro model of DN in podocytes. Cell viability, apoptosis, inflammatory response and insulin-stimulated glucose uptake were evaluated using Cell Counting Kit-8, TUNEL, ELISA and 2-deoxy-D-glucose assay, respectively. In addition, the expression of AMP-activated protein kinase (AMPK)/sirtuin 1 (SIRT1)/NF-κB signaling-related proteins in podocyte cells was measured using western blotting. The results indicated that DSG enhanced the viability of podocytes after HG exposure, but inhibited inflammatory damage and attenuated insulin resistance. Moreover, DSG induced the activation of the AMPK/SIRT1/NF-κB signaling pathway. Furthermore, treatment with compound C, an inhibitor of AMPK, counteracted the protective effects of DSG on HG-induced podocyte cells. Therefore, DSG may be a potential therapeutic compound for the treatment of diabetic nephropathy.

Antidiabetic activity of Berberis brandisiana is possibly mediated through modulation of insulin signaling pathway, inflammatory cytokines and adipocytokines in high fat diet and streptozotocin-administered rats

Medicinal plants play a key role in protection of chronic non-communicable ailments like diabetes, hypertension and dyslipidemia. Berberis brandisiana Ahrendt (Berberidaceae) is traditionally used to treat diabetes, liver problems, wounds, arthritis, infections, swelling and tumors. It is also known to be enriched with multiple phytoconstituents including berbamine, berberine, quercetin, gallic acid, caffeic acid, vanillic acid, benzoic acid, chlorogenic acid, syringic acid, p-coumaric acid, m-coumaric acid and ferulic acid. The efficacy of B. brandisiana has not been established yet in diabetes. This study has been planned to assess the antidiabetic activity of B. brandisiana in high fat diet and streptozotocin (HFD/STZ)-induced diabetes using animals. Administration of aqueous methanolic extract of B. brandisiana (AMEBB) and berbamine (Berb) for 8 weeks caused a dose dependent marked (p < 0.01) rise in serum insulin and HDL levels with a significant decline (p < 0.01) in glucose, triglycerides, glycosylated hemoglobin (HbA1c), cholesterol, LDL, LFTs and RFTs levels when compared with only HFD/STZ-administered rats. AMEBB and Berb also modulated inflammatory biomarkers (TNF-α, IL-6) and adipocytokines (leptin, adiponectin and chemerin). AMEBB (150 mg/kg and 300 mg/kg) and Berb (80 mg/kg and 160 mg/kg) treated rats showed a marked increase (p < 0.001) in catalase levels (Units/mg) in pancreas (42.4 ± 0.24, 47.4 ± 0.51), (38.2 ± 0.583, 48.6 ± 1.03) and liver (52 ± 1.41, 63.2 ± 0.51), (57.2 ± 0.58, 61.6 ± 1.24) and superoxide dismutase levels (Units/mg) in pancreas (34.8 ± 1.46, 38.2 ± 0.58), (33.2 ± 0.80, 40.4 ± 1.96) and liver (31.8 ± 1.52, 36.8 ± 0.96), (30 ± 0.70, 38.4 ± 0.81),respectively while a significant (p < 0.01) decrease in serum melondialdehyde levels (nmol/g) in pancreas (7.34 ± 0.17, 6.22 ± 0.22), (7.34 ± 0.20, 6.34 ± 0.11) and liver (9.08 ± 0.31,8.18 ± 0.29), (9.34 ± 0.10, 8.86 ± 0.24) compared to the data of only HFD/STZ-fed rats. Histopathological studies of pancreas, liver, kidney, heart and aorta revealed restoration of normal tissue architect in AMEBB and Berb treated rats. When mRNA expressions of candidate genes were assessed, AMEBB and Berb showed upregulation of IRS-1, SIRT1, GLUT-4 and downregulation of ADAM17. These findings suggest that AMEBB and Berb possess antidiabetic activity, possibly due to its effect on oxidative stress, glucose metabolism, inflammatory biomarkers and adipocytokines levels. Further upregulation of IRS-1, SIRT1, GLUT-4 and downregulation of ADAM17, demonstrated its potential impact on glucose homeostasis, insulin resistance and chronic inflammatory markers. Thus, this study provides support to the medicinal use of B. brandisiana and berbamine in diabetes.

An Exploratory Study of the Safety and Efficacy of a Trigonella foenum-graecum Seed Extract in Early Glucose Dysregulation: A Double-Blind Randomized Placebo-Controlled Trial

Background: This was an exploratory study to assess the safety and efficacy of a specialized Trigonella foenum-graceum L. seed extract for supporting healthy blood glucose metabolism in a pre-diabetic cohort. Methods: Fifty-four participants were randomised to receive 500 mg/day of T. foenum-graecum seed extract or matching placebo daily for 12 weeks. Fasting blood glucose (FBG), post-prandial glucose (PPBG), HbA1c, fasting insulin (FI), post-prandial insulin (PPI) and C-peptide were assessed at baseline, week 6 and week 12. Lipid levels, liver enzymes and C-reactive protein (CRP), along with safety markers and tolerability were also assessed at baseline and week 12. Results: By week 12 there was a significant difference in FBG (p < 0.001), PPBG (p = 0.007) and triglycerides (p = 0.030) between treatment groups, with no changes in HbA1c (p = 0.41), FI (p = 0.12), PPI (p = 0.50) or C-peptide (p = 0.80). There was no difference in total cholesterol (p = 0.99), high-density lipoprotein (p = 0.35), low density lipoprotein (p = 0.60) or CRP (p = 0.79). There was no change in safety markers and the treatment was well tolerated. Conclusions: The results of the study indicated that T. foenum-graecum seed extract may influence blood glucose metabolism and larger studies are warranted to evaluate efficacy and potential mechanisms of action.

Therapeutic potential and research progress of diosgenin for lipid metabolism diseases

Diosgenin, a steroidal saponin, is a natural product found in many plants. Diosgenin has a wide range of pharmacological activities, and has been used to treat cancer, nervous system diseases, inflammation, and infections. Numerous studies have shown that diosgenin has potential therapeutic value for lipid metabolism diseases via various pathways and mechanisms, such as controlling lipid synthesis, absorption, and inhibition of oxidative stress. These mechanisms and pathways have provided ideas for researchers to develop related drugs. In this review, we focus on data from animal and clinical studies, summarizing the toxicity of diosgenin, its pharmacological mechanism, recent research advances, and the related mechanisms of diosgenin as a drug for the treatment of lipid metabolism, especially in obesity, hyperlipidemia, nonalcoholic fatty liver disease, atherosclerosis, and diabetes. This systematic review will briefly describe the advantages of diosgenin as a potential therapeutic drug and seek to enhance our understanding of the pharmacological mechanism, recipe-construction, and the development of novel therapeutics against lipid metabolism diseases.

Evolutionary research trend of Polygonatum species: a comprehensive account of their transformation from traditional medicines to functional foods

With the advances in Polygonatum research, there is a huge interest in harnessing the valuable functional ingredients of this genus with the potential for functional foods. This review emphasizes the different aspects of Ploygonatum based research starting from its bioactive compounds, their structural characterization, various extraction methods, as well as biological activities. In view of its integral use as an essential medicinal plant, our review emphasizes on its promising food applications both as an ingredient and as a whole food, and its improved health benefits with potential for agricultural and environmental relevance are also discussed. As we collated the recent research information, we present the main challenges and limitations of the current research trend in this area which can upgrade the further expansion of Polygonatum-related research that will strengthen its economic and accessible nutritional value in the food and health industries. By highlighting the need for the unattended species, this review not only fills existing research gaps, but also encourages the researchers to find new avenues for the natural production of bio-based functional materials and the development of highly functional and health-promoting foods for disease prevention and treatment.

Exercise and Stevia Rebaudiana (R) Extracts Attenuate Diabetic Cardiomyopathy in Type 2 Diabetic Rats: Possible Underlying Mechanisms

BACKGROUND AND AIMS

In the current work, we studied the effects of exercise and stevia rebaudiana (R) extracts on diabetic cardiomyopathy (DCM) in type 2 diabetic rats and their possible underlying mechanisms.

METHODS

Thirty-two male Sprague Dawley rats were randomly allocated into 4 equal groups; a) normal control group, b) DM group, type 2 diabetic rats received 2 ml oral saline daily for 4 weeks, c) DM+ Exercise, type 2 diabetic rats were treated with exercise for 4 weeks and d) DM+ stevia R extracts: type 2 diabetic rats received methanolic stevia R extracts. By the end of the experiment, serum blood glucose, HOMA-IR, insulin and cardiac enzymes (LDH, CK-MB), cardiac histopathology, oxidative stress markers (MDA, GSH and CAT), myocardial fibrosis by Masson trichrome, the expression of p53, caspase-3, α-SMA and tyrosine hydroxylase (TH) by immunostaining in myocardial tissues were measured.

RESULTS

T2DM caused a significant increase in blood glucose, HOMA-IR index, serum CK-MB and LDH, myocardial damage and fibrosis, myocardial MDA, myocardial α-SMA, p53, caspase-3, Nrf2 and TH density with a significant decrease in serum insulin and myocardial GSH and CAT (p< 0.05). On the other hand, treatment with either exercise or stevia R extracts significantly improved all studied parameters (p< 0.05). Moreover, the effects of stevia R was more significant than exercise (p< 0.05).

CONCLUSION

Both exercise and methanolic stevia R extracts showed cardioprotective effects against DCM and Stevia R offered more cardioprotective than exercise. This cardioprotective effect of these lines of treatment might be due to attenuation of oxidative stress, apoptosis, sympathetic nerve density and fibrosis and upregulation of the antioxidant transcription factor, Nrf2.

Diosgenin inhibits Wnt/β-catenin pathway to regulate the proliferation and differentiation of MG-63 cells

Dioscorea opposita Thunb has the effect of anti-osteoporosis, but whether its active ingredient diosgenin (DIO) has an anti-osteoporosis effect is unknown. The purpose of this study is to investigate the effect of DIO on the proliferation and differentiation of MG-63 cells. MG-63 cells were treated with different concentrations of DIO (0.001, 0.01, 0.1 and 1 μM) or 20 mM Wnt/β-catenin signaling agonist-LiCl, and then their cell cycle and viability were analyzed by flow cytometry and 3-(4, 5-Dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT), respectively. To investigate osteoblast differentiation, alizarin red staining and ultraviolet spectrophotometer were used to determine the number of calcified nodules and the activity of alkaline phosphatase (ALP), respectively. Quantitative reverse transcription-polymerase chain reaction (qRT-PCR) and western blotting were used to detect the expressions of proliferation-related, osteogenic-related and Wnt/β-catenin signal pathway-related factors. After the cells were treated with low-concentration (0.001 or 0.01 μM) DIO, cell viability was significantly increased and the proportion of cells in S phase was increased. In addition, low-concentration DIO could significantly increase the expression of Ki67, proliferating cell nuclear antigen (PCNA), osteopontin (OPN), and osteocalcin (BGP), promote osteoblast differentiation, and suppress the expression of β-catenin, Runx2 and cyclinD1. However, high concentrations of DIO showed the opposite effect. Low-concentration DIO obviously reversed the effect of LiCl on decreasing the number of calcified nodules and inhibiting the expression of OPN and BGP in cells. Low-concentration DIO might promote the proliferation and differentiation of MG-63 cell by inhibiting the Wnt/β-catenin signal pathway.

Cardioprotective effects of Fenugreek (Trigonella foenum-graceum) seed extract in streptozotocin induced diabetic rats

Introduction: Inadequate control of diabetes mellitus (DM) leads to considerable cardiovascular implications like diabetic cardiomyopathy (DCM). Cardiomyocyte apoptosis is one of the main mechanisms of DCM pathogenesis associated with hyperglycemia, oxidative stress, inflammation, hyperlipidemia and several other factors. Trigonella foenum-graecum (Fenugreek) has been long used as a traditional medicine and has many therapeutic effects, including anti-diabetic, anti-hyperlipidemia, anti-inflammatory and anti-oxidant properties. The current study aimed to investigate cardioprotective effects of fenugreek seed on diabetic rats. Methods: Diabetes was induced in forty-two male rats by injection of streptozotocin (STZ) (60 mg/ kg). Diabetic animals were treated with three different doses of fenugreek seed extract (50, 100 and 200 mg/kg) or metformin (300 mg/kg) for six weeks by gavage. Nondiabetic rats served as controls. Glucose, cholesterol, and triglycerides levels were measured in the blood samples, and oxidative stress markers as well as gene expression of ICAM1 , Bax and Bcl2 were assessed in the cardiac tissues of the experimental groups. Results: Diabetic rats exhibited increased serum glucose, cholesterol and triglycerides levels, elevated markers of oxidative stress thiobarbituric acid-reacting substances (TBARS) levels , total thiol groups (SH), catalase (CAT) and superoxide dismutase (SOD) activity, and enhanced apoptosis cell death (ratio of Bax/Bcl2). Fenugreek seed extract considerably improved metabolism abnormalities, attenuated oxidative stress and diminished apoptosis index. Conclusion: Our study suggests that fenugreek seed may protect the cardiac structure in STZ-induced diabetic rats by attenuating oxidative stress and apoptosis.

Blockade of Renin Angiotensin System Ameliorates the Cardiac Arrhythmias and Sympathetic Neural Remodeling in Hearts of Type 2 DM Rat Model

OBJECTIVE

The present study was designed to investigate the effects of renin angiotensin system (RAS) blockade on cardiac arrhythmias and sympathetic nerve remodelling in heart tissues of type 2 diabetic rats.

METHODS

Thirty-two male Sprague Dawley rats were randomly allocated into 4 equal groups; a) normal control group: normal rats, b) DM group; after type 2 diabetes induction, rats received 2ml oral saline daily for 4 weeks, c) DM+ ACEi: after type 2 diabetes induction, rats were treated with enalapril (10 mg/kg, orally for 4 weeks) and d) DM+ ARBs: after type 2 diabetes induction, rats were treated with losartan (30 mg/kg, orally for 4 weeks).

RESULTS

In type 2 diabetic rats, the results demonstrated significant prolongation in Q-T interval and elevation of blood sugar, HOMA-IR index, TC, TGs, LDL, serum CK-MB, myocardial damage, myocardial MDA, myocardial norepinephrine and tyrosine hydroxylase (TH) density with significant reduction in serum HDL, serum insulin and myocardial GSH and CAT. On the other hand, blockade of RAS at the level of either ACE by enalapril or angiotensin (Ag) receptors by losartan resulted in significant improvement in ECG parameters (Q-T), cardiac enzymes (CK-MB), cardiac morphology, myocardial oxidative stress (low MDA, high CAT and GSH) and myocardial TH density.

CONCLUSION

RAS plays a role in the cardiac sympathetic nerve sprouting and cardiac arrhythmias induced by type 2 DM and its blockade might have a cardioprotective effect via attenuation of sympathetic nerve fibres remodelling, myocardial norepinephrine contents and oxidative stress.

The role of diosgenin in diabetes and diabetic complications

Diabetes mellitus is a chronic and common metabolic disease that seriously endangers human health. Hyperglycemia and long-term metabolic disorders in diabetes will cause damage to the whole body tissues and organs, resulting in serious complications. Nowadays, drugs for treating diabetes on the market has strong side effects, new treatments thus are urgently needed. Natural therapy of natural ingredients is a promising avenue, this is because natural ingredients are safer and they also show strong activity in the treatment of diabetes. Diosgenin is such a very biologically active natural steroidal sapogenin. The research of diosgenin in the treatment of diabetes and its complications has been widely reported. This article reviews the effects of diosgenin through multiple targets and multiple pathways in diabetes and its complications which including diabetic nephropathy, diabetic liver disease, diabetic neuropathy, diabetic vascular disease, diabetic cardiomyopathy, diabetic reproductive dysfunction, and diabetic eye disease.

Comparative Study of the Effects of GLP1 Analog and SGLT2 Inhibitor against Diabetic Cardiomyopathy in Type 2 Diabetic Rats: Possible Underlying Mechanisms

The present study investigated the possible cardioprotective effects of GLP1 and SGLT2i against diabetic cardiomyopathy (DCM) in type 2 diabetic rats and the possible underlying mechanisms.

METHODS

Thirty-two male Sprague Dawley rats were randomly subdivided into 4 equal groups: a) control group, b) DM group, type 2 diabetic rats with saline daily for 4 weeks, c) DM+ GLP1, as DM group with GLP1 analogue (liraglutide) at a dose of 75 µg/kg for 4 weeks, and d) DM+ SGLT2i as DM group with SGLT2 inhibitor (dapagliflozin) at a dose of 1mg/kg for 4 weeks. By the end of treatment (4 weeks), serum blood glucose, homeostasis model assessment insulin resistance (HOMA-IR), insulin, and cardiac enzymes (LDH, CK-MB) were measured. Also, the cardiac histopathology, myocardial oxidative stress markers (malondialdehyde (MDA), glutathione (GSH) and CAT) and norepinephrine (NE), myocardial fibrosis, the expression of caspase-3, TGF-β, TNF-α, and tyrosine hydroxylase (TH) in myocardial tissues were measured.

RESULTS

T2DM caused significant increase in serum glucose, HOMA-IR, serum CK-MB, and LDH (p < 0.05). Also, DM caused significant myocardial damage and fibrosis; elevation of myocardial MDA; NE with upregulation of myocardial caspase-3, TNF-α, TGF-β, and TH; and significant decrease in serum insulin and myocardial GSH and CAT (p < 0.05). Administration of either GLP1 analog or SGLT2i caused a significant improvement in all studied parameters (p < 0.05).

CONCLUSION

We concluded that both GLP1 and SGLT2i exhibited cardioprotective effects against DCM in T2DM, with the upper hand for SGLT2i. This might be due to attenuation of fibrosis, oxidative stress, apoptosis (caspase-3), sympathetic nerve activity, and inflammatory cytokines (TNF-α and TGF-β).

The Biological Impacts of Sitagliptin on the Pancreas of a Rat Model of Type 2 Diabetes Mellitus: Drug Interactions with Metformin

Sitagliptin, a dipeptidyl peptidase-4 (DPP-4) inhibitor, is a beneficial class of antidiabetic drugs. However, a major debate about the risk of developing pancreatitis is still existing. The aim of the work was to study the histological and immunohistochemical effects of sitagliptin on both endocrine and exocrine pancreases in a rat model of type 2 diabetes mellitus and to correlate these effects with the biochemical findings. Moreover, a possible synergistic effect of sitagliptin, in combination with metformin, was also evaluated. Fifty adult male rats were used and assigned into five equal groups. Group 1 served as control. Group 2 comprised of untreated diabetic rats. Group 3 diabetic rats received sitagliptin. Group 4 diabetic rats received metformin. Group 5 diabetic rats received both combined. Treatments were given for 4 weeks after the induction of diabetes. Blood samples were collected for biochemical assay before the sacrification of rats. Pancreases were removed, weighed, and were processed for histological and immunohistochemical examination. In the untreated diabetic group, the islets appeared shrunken with disturbed architecture and abnormal immunohistochemical reactions for insulin, caspase-3, and inducible nitric oxide synthase (iNOS). The biochemical findings were also disturbed. Morphometrically, there was a significant decrease in the islet size and islet number. Treatment with sitagliptin, metformin, and their combination showed an improvement, with the best response in the combined approach. No evidence of pancreatic injury was identified in the sitagliptin-treated groups. In conclusion, sitagliptin had a cytoprotective effect on beta-cell damage. Furthermore, the data didn't indicate any detrimental effects of sitagliptin on the exocrine pancreas.

Evaluation of the andrographolides role and its indoleamine 2,3-dioxygenase inhibitory potential and attendant molecular mechanism against STZ-induced diabetic rats

The study is to scrutinize andrographolides with Indoleamine 2,3-dioxygenase (IDO) inhibitory potential, its molecular mechanism against streptozotocin (STZ) diabetic retinopathy (DR) in Wistar rats. Oxidative stress markers such as Kynurenine metabolites, retinal histopathological changes have been studied. Further, IDO gene expression and docking studies have been performed. Andrographolide treated rats have been reducing the level of thiobarbituric acid reactive substances and protein carbonyls Kynurenine metabolites with an improvement in the level of GSH and expression of IDO as revealed by morphological changes in inner and outer nuclear layer of the retina. The current results of this study have been generated information about an activity of the andrographolide in the essential pocket of IDO. Our results explain, involving IDO and andrographolide would constitute an attempt to identify natural products with therapeutic value and further studies in this direction would be of immense significance in the administration of diabetes and its related problems.

Diosgenin ameliorates palmitic acid-induced lipid accumulation via AMPK/ACC/CPT-1A and SREBP-1c/FAS signaling pathways in LO2 cells

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is the most common chronic liver disease and is characterized by excessive hepatic lipid accumulation. Many studies have suggested that lipid overload is the key initial factor that contributes to hepatic steatosis. Our previous study indicated that diosgenin (DSG) has a beneficial effect on energy metabolism, but the underlying mechanism remains unclear.

METHODS

Human normal hepatocytes (LO2 cells) were incubated with palmitic acid to establish the cell model of nonalcoholic fatty liver. The effects of DSG on lipid metabolism, glucose uptake and mitochondrial function were evaluated. Furthermore, the mechanism of DSG on oxidative stress, lipid consumption and lipid synthesis in LO2 cells was investigated.

RESULTS

The results indicated that palmitic acid induced obvious lipid accumulation in LO2 cells and that DSG treatment significantly reduced the intracellular lipid content. DSG treatment upregulated expression of lipolysis proteins, including phospho-AMP activated protein kinase (p-AMPK), phospho-acetyl-coA carboxylase (p-ACC) and carnitine acyl transferase 1A (CPT-1A), and inhibited expression of lipid synthesis-related proteins, including sterol regulatory element-binding protein 1c (SREBP-1c) and fatty acid synthase (FAS). Additionally, DSG-treated cells displayed a marked improvement in mitochondrial function, with less production of reactive oxygen species and a higher mitochondrial membrane potential compared with the model group.

CONCLUSION

This study suggests that DSG can reduce intracellular lipid accumulation in LO2 cells and that the underlying mechanism may be related to the improving oxidative stress, increasing fatty acid β-oxidation and decreasing lipid synthesis. The above changes might be mediated by the activation of the AMPK/ACC/CPT-1A pathway and inhibition of the SREBP-1c/FAS pathway.

Diosgenin and Its Fenugreek Based Biological Matrix Affect Insulin Resistance and Anabolic Hormones in a Rat Based Insulin Resistance Model

Fenugreek is known since ancient times as a traditional herbal medicine of its multiple beneficial effects. Fenugreek's most studied and employed effect is its hypoglycemic property, but it can also be useful for the treatment of certain thyroid disorders or for the treatment of anorexia. The regulation of glucose homeostasis is a complex mechanism, dependent on the interaction of different types of hormones and neurotransmitters or other compounds. For the study of how diosgenin and fenugreek seeds modify insulin sensitivity, we used a rat insulin resistance model induced by high-fat diet. Diosgenin in three different doses (1mg/bwkg, 10mg/bwkg, and 50 mg/bwkg, respectively) and fenugreek seed (0.2 g/bwkg) were administered orally for 6 weeks. Insulin sensitivity was determined by hyperinsulinemic euglycemic glucose clamp method. Our research group found that although glucose infusion rate was not significantly modified in either group, the increased insulin sensitivity index and high metabolic clearance rate of insulin found in the 1 mg/kg diosgenin and the fenugreek seed treated group suggested an improved peripheral insulin sensitivity. Results from the 10 mg/kg diosgenin group, however, suggest a marked insulin resistance. Fenugreek seed therapy results on the investigated anabolic hormones support the theory that, besides insulin and gastrointestinal peptides, the hypothalamic-hypopituitary axis regulated hormones synchronized action with IGF-1 also play an important role in the maintaining of normal glucose levels. Both diosgenin and fenugreek seeds are capable of interacting with substrates of the above-mentioned regulatory mechanisms, inducing serious hormonal disorders. Moreover, fenugreek seeds showed the ability to reduce the thyroid hormone levels at the periphery and to modify the T4/T3 ratio. It means that in healthy people this effect could be considered a severe side effect; however, in hypothyroidism this effect represents a possibility of alternative natural therapy.

Cardiovascular Effect of Diosgenin in Ovariectomized Rats

Diosgenin is a phytoestrogen and a constituent of Dioscorea. It has several biological effects, and some of them are anti-inflammatory, antidiabetic, antitumor, and vasodilatory. The present study investigated both the vasorelaxing and antioxidant mechanisms of diosgenin in isolated rat aortic rings. Female rats weighing 200-220 g were subjected to sham or OVX operations at 8 weeks of age. Ovariectomy was performed for menopause induction after anesthesia. Diosgenin (10-9 M-3 × 10-4 M) produced a concentration-dependent relaxation in aortic rings precontracted with phenylephrine (1 μM), exhibiting Emax value of 55.34% ± 7.7% (in endothelium-intact rings) and Emax value of 30.30% ± 5.7% (in endothelium-denuded rings). In the endothelium-intact rings, the vasorelaxing effect of diosgenin was reduced by NG-nitro-l-arginine methyl ester (L-NAME) (100 μM), atropine (1 μM), indomethacin (10 μM), 1H-[1,2,4]oxadiazolo-[4,3-a]quinoxalin-1-one (ODQ) (10 μM), 4-aminopyridine (1 mM), tetraethylammonium (3 mM), glibenclamide (10 μM), apamin (10 μM), and Tiron (1 μM). Diosgenin (10-5 M) inhibited the contractions induced by cumulative addition of phenylephrine (10-9-10-5 M). The 28-days treatment with diosgenin (50 mg/kg, v.o.) did not imply changes in the myeloperoxidase parameter, but increased significantly, levels of glutathione, superoxide dismutase, and nitric oxide, as well as reduced the concentration of malondialdehyde related to lipid peroxidation. Our results suggest that diosgenin induced relaxation in aortic rings via an endothelium-dependent pathway, which involves the EDRF, the opening of potassium channels and antioxidant action.

Effects of diosgenin and its derivatives on atherosclerosis

The effects of diosgenin are discussed with respect to endothelial dysfunction, lipid profile, macrophage foam cell formation, VSMC viability, thrombosis and inflammation during the formation of atherosclerosis.

Spice-Derived Bioactive Ingredients: Potential Agents or Food Adjuvant in the Management of Diabetes Mellitus

Spices possess tremendous therapeutic potential including hypoglycemic action, attributed to their bioactive ingredients. However, there is no study that critically reviewed the hypoglycemic potency, safety and the bioavailability of the spice-derived bioactive ingredients (SDBI). Therefore, the aim of the study was to comprehensively review all published studies regarding the hypoglycemic action of SDBI with the purpose to assess whether the ingredients are potential hypoglycemic agents or adjuvant. Factors considered were concentration/dosages used, the extent of blood glucose reduction, the IC50 values, and the safety concern of the SDBI. From the results, cinnamaldehyde, curcumin, diosgenin, thymoquinone (TQ), and trigonelline were showed the most promising effects and hold future potential as hypoglycemic agents. Conclusively, future studies should focus on improving the tissue and cellular bioavailability of the promising SDBI to achieve greater potency. Additionally, clinical trials and toxicity studies are with these SDBI are warranted.

Effects of Duodenal-Jejunal Exclusion and New Bilio-Pancreatic Diversion on Blood Glucose in Rats with Type 2 Diabetes Mellitus

OBJECTIVE

The current study aimed to investigate the effects of duodenal-jejunal bypass (DJB), new bilio-pancreatic diversion (NBPD), and duodenal-jejunal exclusion (DJE) on blood glucose in rats with type 2 diabetes mellitus (T2DM).

METHODS

Male Sprague Dawley rats were fed with high glucose, high fat food, and intraperitoneally injected with streptozotocin to establish a T2DM animal model. T2DM rats were randomly assigned into 4 groups: a sham group (n = 8), DJB group (n = 9), NBPD group (n = 10), and DJE group (n = 10). Body weight, 2-h postprandial glucose, oral glucose tolerance, fasting serum bile acid, 2-h postprandial serum bile acid, fasting insulin, 2-h postprandial insulin (INS), fasting glucagon-like peptide-1 (GLP-1), and 2-h postprandial GLP-1 were measured before and after surgery.

RESULTS

Six weeks after surgery, the 2-h postprandial glucose in the DJB (16.1 ± 6.7 mmol/L) and NBPD (19.5 ± 5.7 mmol/L) groups decreased significantly compared to the sham group (25.8 ± 4.9 mmol/L) (P < 0.05). There was no significant difference between the DJE (25.0 ± 5.0 mmol/L) and sham groups (P > 0.05). Four weeks after surgery, fasting serum bile acid in the DJB group (60.6 ± 11.4 μmol/L) and NBPD group (54.4 ± 7.64 μmol/L) was significantly higher than that in the sham group (34.3 ± 6.98 μmol/L; P < 0.05). However, fasting GLP-1, 2-h postprandial GLP-1, and insulin remained unchanged at different time points after surgery (P > 0.05). Body weight remained stable after surgery in all 4 groups (P > 0.05).

CONCLUSION

NBPD plays a major role in the therapy of T2DM with DJB. NBPD may significantly increase fasting serum bile acid in T2DM rats, an action that may be one of the mechanisms underlying the therapeutic effects of DJB on T2DM.

Natural products for the treatment of type 2 diabetes mellitus: Pharmacology and mechanisms

Epidemiological studies have implied that diabetes mellitus (DM) will become an epidemic accompany with metabolic and endocrine disorders worldwide. Most of DM patients are affected by type 2 diabetes mellitus (T2DM) with insulin resistance and insulin secretion defect. Generally, the strategies to treat T2DM are diet control, moderate exercise, hypoglycemic and lipid-lowing agents. Despite the therapeutic benefits for the treatment of T2DM, most of the drugs can produce some undesirable side effects. Considering the pathogenesis of T2DM, natural products (NPs) have become the important resources of bioactive agents for anti-T2DM drug discovery. Recently, more and more natural components have been elucidated to possess anti-T2DM properties, and many efforts have been carried out to elucidate the possible mechanisms. The aim of this paper was to overview the activities and underlying mechanisms of NPs against T2DM. Developments of anti-T2DM agents will be greatly promoted with the increasing comprehensions of NPs for their multiple regulating effects on various targets and signal pathways.

Chronic diseases, inflammation, and spices: how are they linked?

Extensive research within the last several decades has revealed that the major risk factors for most chronic diseases are infections, obesity, alcohol, tobacco, radiation, environmental pollutants, and diet. It is now well established that these factors induce chronic diseases through induction of inflammation. However, inflammation could be either acute or chronic. Acute inflammation persists for a short duration and is the host defense against infections and allergens, whereas the chronic inflammation persists for a long time and leads to many chronic diseases including cancer, cardiovascular diseases, neurodegenerative diseases, respiratory diseases, etc. Numerous lines of evidence suggest that the aforementioned risk factors induced cancer through chronic inflammation. First, transcription factors NF-κB and STAT3 that regulate expression of inflammatory gene products, have been found to be constitutively active in most cancers; second, chronic inflammation such as pancreatitis, prostatitis, hepatitis etc. leads to cancers; third, activation of NF-κB and STAT3 leads to cancer cell proliferation, survival, invasion, angiogenesis and metastasis; fourth, activation of NF-κB and STAT3 leads to resistance to chemotherapy and radiation, and hypoxia and acidic conditions activate these transcription factors. Therefore, targeting these pathways may provide opportunities for both prevention and treatment of cancer and other chronic diseases. We will discuss in this review the potential of various dietary agents such as spices and its components in the suppression of inflammatory pathways and their roles in the prevention and therapy of cancer and other chronic diseases. In fact, epidemiological studies do indicate that cancer incidence in countries such as India where spices are consumed daily is much lower (94/100,000) than those where spices are not consumed such as United States (318/100,000), suggesting the potential role of spices in cancer prevention.

Molecular determinants of PPARγ partial agonism and related in silico/in vivo studies of natural saponins as potential type 2 diabetes modulators

The metabolic syndrome, which includes hypertension, type 2 diabetes (T2D) and obesity, has reached an epidemic-like scale. Saponins and sapogenins are considered as valuable natural products for ameliorating this pathology, possibly through the nuclear receptor PPARγ activation. The aims of this study were: to look for in vivo antidiabetic effects of a purified saponins' mixture (PSM) from Astragalus corniculatus Bieb; to reveal by in silico methods the molecular determinants of PPARγ partial agonism, and to investigate the potential PPARγ participation in the PSM effects. In the in vivo experiments spontaneously hypertensive rats (SHRs) with induced T2D were treated with PSM or pioglitazone as a referent PPARγ full agonist, and pathology-relevant biochemical markers were analysed. The results provided details on the PSM modulation of the glucose homeostasis and its potential mechanism. The in silico studies focused on analysis of the protein-ligand interactions in crystal structures of human PPARγ-partial agonist complexes, pharmacophore modelling and molecular docking. They outlined key pharmacophoric features, typical for the PPARγ partial agonists, which were used for pharmacophore-based docking of the main PSM sapogenin. The in silico studies, strongly suggest possible involvement of PPARγ-mediated mechanisms in the in vivo antidiabetic and antioxidant effects of PSM from A. corniculatus.

Obesity-alleviating potential of asiatic acid and its effects on ACC1, UCP2, and CPT1 mRNA expression in high fat diet-induced obese Sprague-Dawley rats

The present study evaluated the effects of asiatic acid (AA), a pentacyclic triterpenoid from Centella asiatica on lipid metabolism parameters in a rat model of obesity induced using a high fat diet (HFD) for 42 days. AA (20 mg/kg body weight [BW]) was administered orally once daily for 42 days, and an orlistat-treated group of rats (10 mg/kg BW) was included for comparison. Changes in BW, blood glucose levels, insulin resistance and leptin, adiponectin, amylase, and lipase levels in the blood; lipid profiles of plasma; liver antioxidants levels; and acetyl CoA carboxylase(ACC), uncoupling protein-2 (UCP2), and carnitine palmitoyltransferase-1 (CPT1) mRNA expression were observed in the experimental rats. Our results revealed that AA (20 mg/kg BW), similar to orlistat, reduced the increase in BW; increased bone mineral contents and bone mineral densities; reduced blood glucose levels, insulin resistance, leptin, plasma lipid levels; increased adiponectin, amylase, lipase levels in the blood; showed antioxidant activity; and altered mRNA expression of lipid metabolism-related genes, including ACC, UCP 2, and CPT 1, in the HFD-fed rats. From these results, we concluded that AA possesses significant anti-obesity potential through the suppression of BW gain, lipid lowering action, development of insulin and leptin sensitivity, antioxidant activity, and increased mRNA expression of lipid metabolism-related genes.

Diosgenin and 5-Methoxypsoralen Ameliorate Insulin Resistance through ER-α/PI3K/Akt-Signaling Pathways in HepG2 Cells

To determine the effects and the underlying mechanism of diosgenin (DSG) and 5-methoxypsoralen (5-MOP), two main active components in the classical Chinese prescription Hu-Lu-Ba-Wan (HLBW), on insulin resistance, HepG2 cells were incubated in medium containing insulin. Treatments with DSG, 5-MOP, and their combination were performed, respectively. The result showed that the incubation of HepG2 cells with high concentration insulin markedly decreased glucose consumption and glycogen synthesis. However, treatment with DSG, 5-MOP, or their combination significantly reversed the condition and increased the phosphorylated expression of estrogen receptor-α (ERα), sarcoma (Src), Akt/protein kinase B, glycogen synthase kinase-3β (GSK-3β), and the p85 regulatory subunit of phosphatidylinositol 3-kinase p85 (PI3Kp85). At the transcriptional level, expression of the genes mentioned above also increased except for the negative regulation of GSK-3β mRNA. The increased expression of glucose transport-4 (GLUT-4) was meanwhile observed through immunofluorescence. Nevertheless, the synergistic effect of DSG and 5-MOP on improving glycometabolism was not obvious in the present study. These results suggested that DSG and 5-MOP may improve insulin resistance through an ER-mediated PI3K/Akt activation pathway which may be a new strategy for type 2 diabetes mellitus, especially for women in an estrogen-deficient condition.

Effects of S-Allylcysteine on Biomarkers of the Polyol Pathway in Rats with Type 2 Diabetes

OBJECTIVES

We evaluated the effects of S-allylcysteine (SAC) on biomarkers of the polyol pathway in streptozotocin-nicotinamide (STZ-NA)-induced diabetes in rats.

METHODS

Diabetes was induced in male albino Wistar rats by intraperitoneal administration of STZ (55 mg kg^-1 bw^-1) and NA (110 mg kg^-1 bw^-1). SAC (150 mg kg^-1 bw^-1) was orally administered to the rats with diabetes for 45 days to assess its effects on blood glucose, insulin, insulin resistance, glycated hemoglobin, aldose reductase (AR), sorbitol dehydrogenase (SDH), sorbitol, fructose, thiobarbituric acid-reactive substances (TBARS), hydroperoxide, hemoglobin and glutathione (GSH).

RESULTS

On SAC administration in the rats with diabetes, the levels of blood glucose, insulin resistance, glycated hemoglobin, AR, SDH, sorbitol, fructose, TBARS and hydroperoxide increased significantly (p<0.05), whereas those of insulin, hemoglobin and GSH decreased. SAC showed therapeutic effects similar to those of gliclazide in decreasing blood glucose, AR, SDH, sorbitol, fructose, glycosylated hemoglobin, TBARS and hydroperoxides levels and significant increases in insulin, hemoglobin and GSH activity in rats with diabetes. Moreover, histopathologic studies also revealed the protective effect of SAC on pancreatic beta cells.

CONCLUSIONS

The results indicate that SAC prevents complications of diabetes by reducing the influx of glucose in the polyol pathway, thereby elevating the GSH level and reducing the activities of AR and SDH. Therefore, SAC may have imperative implications for the deterrence and early treatment of type 2 diabetes.

α-glucosidase and glycation inhibitory effects of costus speciosus leaves

BACKGROUND

Hyperglycaemia is a salient feature of poorly controlled diabetes mellitus. Rate of protein glycation is increased with hyperglycaemia leading to long term complications of diabetes. One approach of controlling blood glucose in diabetes targets at reducing the postprandial spikes of blood glucose. The objectives of this study were to assess the in vitro inhibitory effects of Costus speciosus (COS) leaves on α-amylase and α-glucosidase activities, fructosamine formation, protein glycation and glycation-induced protein cross-linking.

METHODS

Methanol extracts of COS leaves were used. Inhibitory effects on enzyme activities were measured using porcine pancreatic α-amylase and α-glucosidase from Saccharomyces cerevisiae in the presence of COS extract. Percentage inhibition of the enzymes and the IC50 values were determined. In vitro protein glycation inhibitory effect of COS leaves on early and late glycation products were measured using bovine serum albumin or chicken egg lysozyme with fructose. Nitroblue tetrazolium was used to assess the relative concentration of fructosamine and polyacrylamide gel electrophoresis was used to assess the degree of glycation and protein cross-linking in the reaction mixtures.

RESULTS

α-Glucosidase inhibitory activity was detected in COS leaves with a IC50 of 67.5 μg/ml which was significantly lower than the IC50 value of Acarbose (p < 0.01). Amylase inhibitory effects occurred at a comparatively higher concentration of extract with a IC50 of 5.88 mg/ml which was significantly higher than the IC50 value of Acarbose (p < 0.01). COS (250 μg/ml) demonstrated inhibitory effects on fructosamine formation and glycation induced protein cross-linking which were in par with 1 mg/ml aminoguanidine were detected.

CONCLUSION

Methanol extracts of COS leaves demonstrated in vitro inhibitory activities on α-glucosidase, fructosamine formation, glycation and glycation induced protein cross-linking. These findings provide scientific evidence to support the use of COS leaves for hypoglycemic effects with an added advantage in slowing down protein glycation.

A review on possible therapeutic targets to contain obesity: The role of phytochemicals

The prevalence and severity of obesity has increased markedly in recent decades making it a global public health concern. Since obesity is a potential risk factor in the development of hypertension, type-2 diabetes, cardiovascular diseases, infertility, etc., it is no more viewed as a cosmetic issue. Currently, only a few FDA-approved anti-obesity drugs like Orlistat, Lorcaserin and Phentermine-topiramate are available in the market, but they have considerable side effects. On the other hand, bariatric surgery as an alternative is associated with high risk and expensive. In view of these there is a growing trend towards natural product-based drug intervention as one of the crucial strategies for management of obesity and related ailments. In Asian traditional medicine and Ayurvedic literature a good number of plant species have been used and quoted for possible lipid-lowering and anti-obesity effects; however, many of them have not been evaluated rigorously for a definite recommendation and also lack adequate scientific validation. This review explores and updates on various plant species, their used parts, bioactive components and focuses multiple targets/pathways to contain obesity which may pave the way to develop novel and effective drugs. We also summarised different drugs in use to treat obesity and their current status. Nature is future promise of our wellbeing.