Antidiabetic effects of Eugenia jambolana in the streptozotocin-induced diabetic male albino rat

Treatment with Terminalia chebula Extract Reduces Insulin Resistance, Hyperglycemia and Improves SIRT1 Expression in Type 2 Diabetic Rats

BACKGROUND

Terminalia chebula Retz., Family Combretaceae (T. chebula) is one of the important plants mentioned in Ayurveda, a traditional system of medicine. The present work was designed to study the effect of the aqueous extract of T. chebula fruits in type 2 diabetic rats.

METHODS

The aqueous extract of the fruits was prepared by the double maceration technique. The extract was subjected to HPTLC analysis, which showed the presence of ellagic acid and gallic acid. Type 2 diabetes was induced in rats with a low dose of Streptozotocin (35 mg/kg) after administering a high-fat diet for fourteen days. Diabetic animals were treated with 500 and 1000 mg/kg of aqueous extract of T. chebula fruits for six weeks.

RESULTS

Diabetic rats showed a significantly (511.7 ± 17.6) (p < 0.001) high plasma glucose level compared to the normal group (106 ± 3.358). The T. chebula treatment group showed a significant (p < 0.001) reduction in plasma glucose at 500 mg/kg (394.3 ± 10.35) and 1000 mg/kg (368.6 ± 30.08) doses when compared with the diabetic control group. Treatment with aqueous extract significantly reduced lipid parameters in diabetic animals when compared to the animals in the diabetic control group. Treatment with extract at a dose of 500 mg/kg and 1000 mg/kg showed a significant reduction in AST (p < 0.01, p < 0.001) when compared with diabetic control rats. Treatment with extract significantly reduced ALT at 500 mg/kg (p < 0.05) and 1000 mg/kg (p < 0.001) doses when compared with diabetic control rats. The extract treatment improved insulin sensitivity and insulin sensitivity index (ISI) and significantly decreased HOMR-IR. Treatment with T. chebula aqueous extract at 1000 mg/kg significantly increased the level of GSH (p < 0.05) when compared to diabetic control rats. T. chebula treatment at 1000 mg/kg significantly increased levels of CAT (p < 0.01). Histopathology of pancreatic tissue revealed that the extract has a protective effect against the damage caused by hyperglycemia. Immunohistochemistry of pancreatic tissue showed increased expression of SIRT1 in diabetic animals treated with the extract.

CONCLUSIONS

The results of the present study indicate that the extract of T. chebula has significant effects in the management of type 2 diabetes.

Plant bioactive compounds and their mechanistic approaches in the treatment of diabetes: a review

Background

Diabetes mellitus (DM) is a growing disease across the world; diabetes is a complex metabolic disorder in which blood glucose concentration level increases and continue for a prolonged period due to a decrease secretion of insulin or action, resulting in the disorder of carbohydrate, lipid, and protein metabolism. The plant-related bioactive compounds have proven their efficacy with least toxicities and can be utilized for the disease treatment. Our objective is to elucidate the mechanism of action of plant bioactive compounds which can give future direction in diabetes treatment.

Main body

In this review paper, we briefly study more than 200 research papers related to disease and bioactive compounds that have therapeutic applicability in treatment. The plant contains many bio-active compounds which possess in vitro and in vivo anti-diabetic effect which may be responsible for the hypoglycaemic property by inhibiting the digestive enzyme i.e. alpha-amylase and alpha-glucosidase, by producing mimetic action of insulin, by reducing the oxidative stress, by showing antihyperglycemic activity and hypolipidemic activity, by inhibition of aldose reductase, and by increasing or enhancing glucose uptake and insulin secretion.

Conclusion

Our study revealed that terpenes, tannin, flavonoids, saponin, and alkaloids are important bioactive constituents for anti-diabetic activity. The mechanistic approach on alpha-glucosidase and alpha-amylase, hypolipidemic activity, and AR inhibitory action clear-cut explain the therapeutic applicability of these bioactive compounds in disease. Plants that contain these bioactive compounds can be good drug candidates for future research on diabetes treatment.

Pharmacologically Active Phytomolecules Isolated from Traditional Antidiabetic Plants and Their Therapeutic Role for the Management of Diabetes Mellitus

Diabetes mellitus is a chronic complication that affects people of all ages. The increased prevalence of diabetes worldwide has led to the development of several synthetic drugs to tackle this health problem. Such drugs, although effective as antihyperglycemic agents, are accompanied by various side effects, costly, and inaccessible to the majority of people living in underdeveloped countries. Medicinal plants have been used traditionally throughout the ages to treat various ailments due to their availability and safe nature. Medicinal plants are a rich source of phytochemicals that possess several health benefits. As diabetes continues to become prevalent, health care practitioners are considering plant-based medicines as a potential source of antidiabetic drugs due to their high potency and fewer side effects. To better understand the mechanism of action of medicinal plants, their active phytoconstituents are being isolated and investigated thoroughly. In this review article, we have focused on pharmacologically active phytomolecules isolated from medicinal plants presenting antidiabetic activity and the role they play in the treatment and management of diabetes. These natural compounds may represent as good candidates for a novel therapeutic approach and/or effective and alternative therapies for diabetes.

Structural characterization of a novel polysaccharide from sweet corncob that inhibits glycosylase in STZ-induced diabetic rats : Structural characterization of a novel polysaccharide

In the current study, we extracted a polysaccharide from sweet corncob and evaluated its hypoglycemic function. After collection in water, alcohol precipitation, and purification by DEAE-52 and Sephadex G-100 columns, we obtained a polysaccharide (SCP50) that was composed primarily of mannose and glucose (9.73:190.27), with a molecular weight of 9280.33 Da. We demonstrated that SCP50 exhibited significant inhibition of α-glucosidase activity, with an IC50 of 4.866 mg/mL, K_m of 1.297 × 10^-3, and V_max of 0.076 mol/L·min^-1 in vitro. We also observed that SCP50 markedly attenuated disaccharidase (maltase, sucrase, and lactase) activity in a rat model of T2DM. We conclude that SCP50 exerts a hypoglycemic effect via inhibition of intestinal glycosylase. These results thus provide new insight into the hypoglycemic action underlying sweet corncob polysaccharide's effects.

Establishment of long-term high-fat diet and low dose streptozotocin-induced experimental type-2 diabetes mellitus model of insulin resistance and evaluation of seed extracts of Syzygium cumini

Introduction: The principal mechanism responsible for reducing blood glucose is through insulin-stimulated glucose transport into skeletal muscle. The transporter protein that mediates this uptake is GLUT-4. A defect in this step is associated with reduced glucose utilization in muscle and adipose tissue, as observed in insulin-resistant type-2 diabetes mellitus (T2DM) patients. This study aimed to develop an experimental T2DM model and evaluate altered glucose transporter type 4 (GLUT-4) levels as a biomarker of insulin resistance. Antidiabetic activities of Syzygium cumini hydro-ethanolic seed extracts (SCE) were also evaluated. Methods: Adult male Wistar albino rats were fed a high-fat diet for 12 weeks and dosed intraperitoneally with streptozotocin (35 mg/kg). After treatment for 21 days, all investigations were done. The homeostasis model of assessment (HOMA) was used for the calculation of insulin resistance (HOMA-IR) and beta-cell function (HOMA-B) index. Diaphragm muscle and retroperitoneal fat were collected for real-time polymerase chain reaction (RT-PCR) studies. Results: A significant increase in fasting blood glucose, HOMA-IR, and serum lipids, and a decrease in serum insulin and HOMA-B were observed in the diabetic group, effects that reversed following pioglitazone and SCE treatment. The diabetic group showed a downregulation of GLUT-4 expression in skeletal muscle while an increase was observed in adipose tissue. Conclusion: A high-fat diet and low dose streptozotocin-induced experimental T2DM model of insulin resistance was developed to screen novel insulin sensitizers. Data generated demonstrated that altered GLUT-4 levels could be used as a biomarker of insulin resistance. Antidiabetic activity of S. cumini hydro-ethanolic seed extract was also confirmed in this study.

Effects of 22 traditional anti-diabetic medicinal plants on DPP-IV enzyme activity and glucose homeostasis in high-fat fed obese diabetic rats

The present study investigated the effects of hot water extracts of 22 medicinal plants used traditionally to treat diabetes on Dipeptidyl peptidase-IV (DPP-IV) activity both in vitro and in vivo in high-fat fed (HFF) obese-diabetic rats. Fluorometric assay was employed to determine the DPP-IV activity. For in vivo studies, HFF obese-diabetic rats were fasted for 6 h and blood was sampled at different times before and after the oral administration of the glucose alone (18 mmol/kg body weight) or with either of the four most active plant extracts (250 mg/5 ml/kg, body weight) or established DPP-IV inhibitors (10 μmol/5 ml/kg). DPP-IV inhibitors: sitagliptin, vildagliptin and diprotin A, decreased enzyme activity by a maximum of 95-99% (P<0.001). Among the 22 natural anti-diabetic plants tested, AnogeissusLatifolia exhibited the most significant (P<0.001) inhibitory activity (96 ± 1%) with IC50 and IC25 values of 754 and 590 μg/ml. Maximum inhibitory effects of other extracts: Aegle marmelos, Mangifera indica, Chloropsis cochinchinensis, Trigonella foenum-graecum and Azadirachta indica were (44 ±7%; 38 ± 4%; 31±1%; 28±2%; 27±2%, respectively). A maximum of 45% inhibition was observed with >25 μM concentrations of selected phytochemicals (rutin). A.latifolia, A. marmelos, T. foenum-graecum and M. indica extracts improved glucose tolerance, insulin release, reduced DPP-IV activity and increased circulating active GLP-1 in HFF obese-diabetic rats (P<0.05-0.001). These results suggest that ingestion of selected natural anti-diabetic plants, in particular A. latifolia, A. marmelos, T. foenum-graecum and M. indica can substantially inhibit DPP-IV and improve glucose homeostasis, thereby providing a useful therapeutic approach for the treatment of T2DM.

Correction of glycemic and oxidative stress sensors in streptozotocin induced diabetic rat model: Impact of dose dependent study of n-butanol solvent fraction of hydro-methanol extract of banana flower (Musa balbisiana)

The experiment focused the most effective dose out of 2.5, 5, and 10 mg/100 g body weight/day for 4 weeks of n-butanol fraction from the pretested promising hydro-methanol extract of Musa balbisiana flower to manage the streptozotocin-induced diabetes in rat and to minimize the bioburden of the body by excluding the inactive components from the said extract. Fraction treatment exhibited an outstanding recovery in fasting blood glucose, glycated hemoglobin, serum insulin levels, carbohydrate metabolic, antioxidant enzymes activities, expression of their marker genes, and apoptotic gene in diabetic rat. Flow-cytometric study of pancreatic β-cell population was significantly recovered in fraction-treated groups which was also supported by histological study. The moderate dose, that is, 5 mg dose showed maximum efficacy in respect to other doses. The high dose, that is, 10 mg dose is not significantly effective than 5 mg dose may be due to the desensitization of the target organ's orphan receptor(s). PRACTICAL APPLICATIONS: The work includes the role of M. balbisiana on diabetes management. Result focused that M. balbisiana flower can able to rectify the diabetic condition and recovered the β cell population. M. balbisiana flower is a very common vegetable to people, use mostly in their daily meal. The experiment showed positive results to cure diabetes in the long-term. Moreover, this study is potential for drug development using nutraceutical(s) isolation. The pharmaceutical companies may develop an antidiabetic drug from the concerned plant part after successful clinical trial.

Phytoecdysteroids from Ajuga iva act as potential antidiabetic agent against alloxan-induced diabetic male albino rats

The present study investigated the protective effect of phytoecdysteroids extracted from the Ajuga iva plant on body weight changes, blood glucose, insulin total protein, blood urea nitrogen (BUN), creatinine, triglycerides (TG), cholesterol, lipid peroxidation, antioxidant enzymes, pancreatic histopathology and hexokinase-I expression in the alloxan-induced diabetic rats. Experimental diabetes was induced following 15day intraperitoneal administration of alloxan. The rats were divided into four groups. Group I served as a sham group, and group II served as the diabetic control. Group III served as a treatment for phytoecdysteroids (10mg/kg), and group IV served as a treatment for phytoecdysteroids (20mg/kg). Phytoecdysteroids restored body weight loss to its antihyperglycemic effect. Blood glucose was reduced 19.2 and 52.9% in group III and IV respectively. Blood insulin (54.9 and 105.88%) and total protein (25 and 72.2%) was increased in group III and IV respectively. BUN, creatinine, TG, cholesterol and lipid peroxidation was significantly reduced following treatment. Catalase, superoxide dismutase (SOD), and glutathione peroxidase activity were significantly increased following treatment. Islet β-cells are lost in alloxan-induced diabetic rats. Regeneration of islets and reduced atrophy of acinar cells were noted. The number of insulin-secreting cells was tremendously reduced in alloxan-induced diabetic rats. Insulin-secreting cells were increased 48 and 61% in group III and IV respectively. Hexokinase-I mRNA (28.3 & 93.5%) and protein (27.9 and 55.3%) expression were significantly increased following treatment. Taking all these data together, it is suggested that the phytoecdysteroid could be a potential therapeutic agent against experimental diabetes.