Hypoglycaemic and anti-diabetic activity of stem bark extracts Erythrina indica in normal and alloxan-induced diabetic rats

Evaluation of acute oral toxicity, anti-diabetic and antioxidant effects of Aloe vera flowers extract

ETHNOPHARMACOLOGICAL RELEVANCE

Aloe vera (L.) Burm.f. is widely used in various traditional systems of medicine worldwide. Since over 5000 years ago, several cultures have used A. vera extract medicinally for conditions ranging from diabetes to eczema. It has been shown to reduce the symptoms of diabetes by enhancing insulin secretion and protecting pancreatic islets.

AIM OF THE WORK

This research study aimed to investigate the in-vitro antioxidant effect, the acute oral toxicity, and the possible pharmacological in-vivo anti-diabetic activity with histological examination of the pancreas of the standardized deep red A. vera flowers methanolic extracts (AVFME).

MATERIALS AND METHODS

The liquid-liquid extraction procedure and TLC technique were used to investigate chemical composition. Total phenolics and flavonoids in AVFME were quantified by Folin-Ciocalteu and AlCl₃ colorimetric methods, respectively. The present study involved evaluating the in-vitro antioxidant effect of AVFME using ascorbic acid as the reference standard, an acute oral toxicity study by using thirty-six albino rats and different concentrations of AVFME (200 mg/kg, 2, 4, 8 and 10 g/kg b.w.). Furthermore, the in-vivo anti-diabetic study was performed on alloxan-induced diabetes in rats (120 mg/kg, I.P.) and two doses of AVFME (200 and 500 mg/kg b.w., orally) were used as compared to glibenclamide (5 mg/kg, orally) as a standard hypoglycemic sulfonylurea medication. A histological examination of the pancreas was performed.

RESULTS

AVFME resulted in the highest phenolic content of 150.44 ± 4.62 mg gallic acid equivalent per gram (GAE/g) along with flavonoid content of 70.38 ± 0.97 mg of quercetin equivalent per gram (QE/g). An in-vitro study revealed that the antioxidant effect of AVFME was strong as ascorbic acid. The results of the in-vivo studies showed that the AVFME didn't cause any apparent toxicity signs or death in all groups at different doses which proves the safety of this extract with a wide therapeutic index. The antidiabetic activity of AVFME demonstrated a considerable drop in blood glucose levels as glibenclamide, without severe hypoglycemia or significant weight gain which is considered an advantage of AVFME over glibenclamide use. The histopathological study of pancreatic tissues confirmed the protective effect of AVFME on the pancreatic beta-cells. The extract is proposed to have antidiabetic activity through inhibition of α-amylase, α-glucosidase, and dipeptidyl peptidase IV (DPP-IV). Molecular docking studies were conducted to understand possible molecular interactions with these enzymes.

CONCLUSION

AVFME represents a promising alternative source of active constituents against diabetes mellitus (DM) based on its oral safety, antioxidant, anti-hyperglycemic activities, and pancreatic protective effects. These data revealed the antihyperglycemic activity of AVFME is mediated by pancreatic protective effects while significantly enhancing insulin secretion through increasing functioning beta cells. This suggests that AVFME has the potential as a novel antidiabetic therapy or a dietary supplement for the treatment of type 2 diabetes (T2DM).

Effects of Vincamine on Testicular Dysfunction in Alloxan-induced Diabetic Male Rats

Background

Diabetes mellitus (DM) is frequently linked with problems of several organ systems, including retinopathy, neuropathy, and nephropathy. Additionally, patients have changes in sexual functioning, such as decreased libido and fertility. Vincamine, a monoterpenoid indole alkaloid, has hypoglycemic and antioxidant effects.

Objectives

This research assessed the impact of vincamine on testicular dysfunction in alloxan-induced male rats by measuring fasting blood glucose, oxidative stress, seminal analysis, and histological examination of the testis.

Methods

Wister-albino male rats were randomized into the following groups at random: Untreated-healthy, untreated-DM, vincamine-treated (20 mg/kg) DM, vincamine-treated (40 mg/kg) DM, and clomiphene-treated DM (5 mg/kg). On day 14, rats were sacrificed, and semen/blood samples were collected. Sperm count, motility, and morphological abnormalities were noted by microscopic examination. The testis was examined histopathologically and assessed using Johnsen's score.

Results

Compared with the untreated diabetic group, a dosage of 40 mg/kg vincamine generate a significant reduction in fasting blood sugar (FBG). Compared with the untreated diabetic group, the vincamine-treated rats produced greater plasma testosterone levels and Johnsen scores. In the vincamine 20 mg/kg group, sperm concentration was higher than in the vincamine 40 mg/kg group.

Conclusions

It is possible that vincamine has a potential preventive effect against diabetes-related reproductive problems attributable to its antioxidant activity and capacity to restore testicular steroidogenesis.

Assessment of antidiabetic potential of Musa acuminata peel extract and its fractions in experimental animals and characterisation of its bioactive compounds by HPTLC

Musa acuminata is a rich source of nutritional food with acclaimed therapeutic uses. Banana pulp has been reported to possess antidiabetic properties. The present study aimed to investigate antidiabetic potential of Musa acuminata peels and its fractions along with diabetic complications. Animals were divided into various groups (n = 6), EMA 100, 200 and 400 mg/kg/day and various fractions 50 and 100 mg/kg/day along with vehicle administered orally to alloxan-induced diabetic rats (n = 6) for 21 days for extract and for 7 days for fractions. Musa acuminata possess antidiabetic potential by reducing plasma glucose by utilising glucose in the periphery and production of hepatic glycogen and further reduce protein catabolism which is responsible for improvement in body weight along with reduction in diabetic complications such as dyslipidemia, peripheral neuropathy and nephropathy. Protective role of Musa acuminata in treatment of diabetes and its complications.

Evaluation of the Hypoglycemic Potential of Leaves Extract of Spondias pinnata (L.f.) Kurz. from Nepal

Spondias pinnata (L.f.) Kurz. (family: Anacardiaceae) is a wild deciduous tree indigenous to southeast Asian countries. Different parts of this plant are used traditionally for the treatment and cure of various disorders and illnesses. S. pinnata leaves are used to prevent and treat diabetes in traditional Balinese medicine. However, scientific study on the antihyperglycemic effect of its leaves has not been reported yet. Therefore, this study aims to perform phytochemical screening and investigate the hypoglycemic potential of S. pinnata leaves extract. Preliminary phytochemical screening of the hydroethanolic extract was performed following the standard tests. In vivo hypoglycemic activity of the leaves extract was evaluated using normal and glucose-loaded rats. The results displayed the presence of phytochemical constituents such as saponins, phenolic compounds, flavonoids, and terpenoids. S. pinnata (500 mg/kg) and metformin (100 mg/kg) exhibited a significant (p < 0.05) decrease in blood glucose level at 1, 2, and 3 h in normal rats when compared to the control group. Metformin- (100 mg/kg)- and S. pinnata- (500 mg/kg)- treated groups showed a maximum decrease in the blood glucose level at 3 h after single-dose administration in the oral glucose tolerance test (OGTT). In conclusion, S. pinnata leaves possess a significant hypoglycemic activity in the animal model and thus support its traditional use to treat diabetes. Therefore, a detailed mechanism-based study and isolation of bioactive compounds from S. pinnata leaves would be beneficial in the future for the search of new hypoglycemic agents.

The genus Erythrina L.: A review on its alkaloids, preclinical, and clinical studies

Erythrina L. genus (Fabaceae) comprises about 115 species, and it has been extensively studied, mainly because of its alkaloids, which have pharmacological properties. References demonstrated that Erythrina spp. have a potential to act in the central nervous system, presenting anxiolytic and anticonvulsant properties already established. Phytochemical investigations confirmed the presence of tetracyclic alkaloids as the major compounds. However, other alkaloid classes have also been reported, including dimeric and trimeric substances, coupled through direct polymerization or two erythrinine units via an acetyl glucose. The present review covers the relevant literature from 1990 until 2017 and outlines the current data on chemical composition and preclinical and clinical studies on Erythrina species. Additionally, the quite striking analogy in the biosynthetic route of erythrin, morphinans, and Amaryllidaceae family alkaloids was also discussed.

Effects of Three Different Frequencies of Aerobic Physical Activity on Heart and Kidney Tissues in Type 2 Diabetes-Induced Rats

Objective:

Exercise has many beneficial effects in the treatment and prevention of Type 2 Diabetes Mellitus (T2DM). The aim of this study was to evaluate the effect of physical activities with different frequencies performed within a total total duration of one week on the heart and kidney tissues and vascular endothelial growth factor (VEGF) expressions in experimental T2DM model.

Method:

Rats (n: 30) were divided into sedentary control (SC), sedentary T2DM (SD), T2DM and continuous exercise (DEc, 30 min/day, 5 days/week), T2DM and short bouts exercise (DEsb, 3x10 min/day, 5 days/week), T2DM and weekend warrior exercise (DEww, 35+40 min/day, 2 days/week) groups. Rats were administered streptozotocin (65 mg/kg) and nicotinamide (110 mg/kg) through intraperitoneal route. After 6-weeks of swimming exercise (total duration 150 min/week), biochemical analyzes were performed to measure oral glucose tolerance test, insulin sensitivity and cytokines. Histopathological and immunohistochemical analyses [VEGF, capillary density, Transforming growth factor beta (TGF-β)] were performed in heart and kidney tissues.

Results:

Compared with sedentary T2DM rats, significant improvements were observed in all exercise groups in terms of blood glucose level, insulin sensitivity, capillary density in heart tissue, VEGF expressions in tissues, TGF-β expressions in kidney tissue and all histopathological analysis (p<0.05).

Conclusion:

This study shows that physical activity at various frequencies may significantly ameliorate harmful effects of T2DM on heart and kidney tissue without significant differences between exercise frequencies, provided that the total duration of aerobic exercise remains the same (150 min/week).

Antidiabetic activity, glucose uptake stimulation and α-glucosidase inhibitory effect of Chrysophyllum cainito L. stem bark extract

Background

Chrysophyllum cainito L., a tropical fruit tree, has been used as an alternative medicine for the treatment of diabetic patients in many countries. However, there is very limited scientific rationale for this medical use. The present study aimed to evaluate the antidiabetic activity of the extract from C. cainito stem bark and the possible mechanisms underlying this activity.

Methods

Phytochemistry and in vitro antioxidant capacity of the extract were studied. Hypoglycemic activity of the extract was examined in normal and alloxan-induced diabetic mice. The effect of C. cainito extract on glucose absorption and glucose uptake were conducted using mouse isolated jejunum and abdominal muscle, respectively. Finally, an in vitro effect of C. cainito extract on α-glucosidase activity was evaluated.

Results

C. cainito extract possessed a strong antioxidant activity comparable to the ascorbic acid and butylated hydroxytoluene. The extract at 500 mg/kg significantly reduced the area under curve of blood glucose level in oral glucose tolerance test in normal mice. In alloxan-induced diabetic model, similar to glibenclamide, a single dose of the extract significantly decreased fasting blood glucose level from 387.17 ± 29.84 mg/dl to 125.67 ± 62.09 mg/dl after 6 h of administration. From the isolated jejunum experiment, the extract at any doses used did not inhibit glucose absorption. However, the extract at 50 μg/ml significantly increased the amount of glucose uptake by abdominal muscles in the presence of insulin (P < 0.05). Lastly, it was found that the extract produced stronger inhibition of α-glucosidase activity (IC₅₀ = 1.20 ± 0.09 μg/ml) than acarbose (IC₅₀ = 198.17 ± 4.74 μg/ml).

Conclusion

Direct evidence of antidiabetic activity of C. cainito stem bark with possible modes of action, glucose uptake stimulation and α-glucosidase inhibitory effect, was reported for the first time herein. These data support the potential use of this plant for the treatment of diabetic patients.

Suppression of Type-II Diabetes with Dyslipidemia and Nephropathy by Peels of Musa cavendish Fruit

Musa cavendish, peels has local and traditional use to promote wound healing, hyperglycemia, ulceration etc. The present work investigated the lipid lowering; nephroprotective and glucose lowering properties of ethanolic extract of peels of Musa cavendish (EMC) in alloxan-induced diabetic rats. The EMC 250, 500 and 1000 mg/kg/day and the vehicle were administered orally to alloxan-induced diabetic rats (n = 6) for 3 weeks. Changes in plasma glucose, lipid profile along with kidney function before and after treatment with EMC were recorded. The ethanolic extract of peels of Musa cavendish reduced blood glucose, serum triglyceride, cholesterol, LDL cholesterol and creatinine levels and improvement in body weight, liver glycogen, serum HDL cholesterol, serum albumin and total protein level when compared with untreated rats. Musa cavendish has lipid lowering, nephroprotective and antidiabetic property by regulating glucose uptake in the liver and muscles by restoring the intracellular energy balance.

Anti-diabetic and spasmolytic potential of Farsetia hamiltonii Royle from Cholistan desert

ETHNOPHARMACOLOGICAL RELEVANCE

Folk herbal practitioners of the Cholistan desert claim Farsetia hamiltonii Royle (Brassicaceae) to treat diabetes, oxidative damages, diarrhea, fever, and abdominal cramps. The aim of this study was to scientifically find the potential of Farsetia hamiltonii in treating diabetes and gastrointestinal diseases.

MATERIALS AND METHODS

In vivo anti-diabetic activity of Farsetia hamiltonii was studied on alloxan induced diabetic rats to justify its traditional use. The in vitro antispasmodic activity on isolated tissues of rabbit jejunum was also evaluated. In addition, several enzyme inhibition studies (lipoxygenase, tyrosinase, acetylcholinesterase (AchE), carbonic II anhydrase and phosphodiesterase I) and antioxidant activity of plant extracts were also conducted.

RESULTS

In vivo experiments, Farsetia hamiltonii methanol extract (300 mg/kg) significantly lowered the fasting blood glucose (107.6 ± 1.249 mg/dL up to 4th day) comparable to positive control (Glibenclamide) throughout the study period. The in vitro antispasmodic activity on isolated tissues of rabbit jejunum on methanol extract showed concentration dependent (0.01-0.3 mg/ml) relaxation of spontaneous contractions with EC₅₀ value 0.011 µM and high K(+) (80 mM) induced contraction (0.01-0.1 mg/ml) with EC₅₀ value 0.066 mg/ml. Farsetia hamiltonii DCM and methanol extracts exhibited some antilipoxygenase activities while tyrosinase, acetylcholinesterase (AchE), carbonic II anhydrase, phosphodiesterase I, and antioxidant activity of plant extracts were not significant.

CONCLUSIONS

Our results validate the traditional use of Farsetia hamiltonii for the traditional therapeutic potential in treating diabetes and gastrointestinal diseases.

Effects of olive leave extract on metabolic disorders and oxidative stress induced by 2.45 GHz WIFI signals

We investigated the effect of olive leaves extract administration on glucose metabolism and oxidative response in liver and kidneys of rats exposed to radio frequency (RF). The exposure of rats to RF (2.45 GHz, 1h/day during 21 consecutive days) induced a diabetes-like status. Moreover, RF decreased the activities of glutathione peroxidase (GPx, -33.33% and -49.40%) catalase (CAT, -43.39% and -39.62%) and the superoxide dismutase (SOD, -59.29% and -68.53%) and groups thiol amount (-62.68% and -34.85%), respectively in liver and kidneys. Indeed, exposure to RF increased the malondialdehyde (MDA, 29.69% and 51.35%) concentration respectively in liver and kidneys. Olive leaves extract administration (100 mg/kg, ip) in RF-exposed rats prevented glucose metabolism disruption and restored the activities of GPx, CAT and SOD and thiol group amount in liver and kidneys. Moreover, olive leave extract administration was able to bring down the elevated levels of MDA in liver but not in kidneys. Our investigations suggested that RF exposure induced a diabetes-like status through alteration of oxidative response. Olive leaves extract was able to correct glucose metabolism disorder by minimizing oxidative stress induced by RF in rat tissues.

Isolation of Antidiabetic Principle from Fruit Rinds of Punica granatum

Present study was aimed to isolate and evaluate the antidiabetic activity of phytoconstituents from fruit rinds of Punica granatum. With the above objectives Valoneic acid dilactone (VAD) was isolated from methanolic fruit rind extracts of Punica granatum (MEPG) and confirmed by ¹H-NMR, ¹³C-NMR, and mass spectral data. Antidiabetic activity was evaluated by Aldose reductase, α-amylase and PTP1B inhibition assays in in vitro and Alloxan-induced diabetes in rats was used as an in vivo model. In bioactivity studies, MEPG and VAD have showed potent antidiabetic activity in α-amylase, aldose reductase, and PTP1B inhibition assays with IC₅₀ values of 1.02, 2.050, 26.25 μg/mL and 0.284, 0.788, 12.41 μg/mL, respectively. Furthermore, in alloxan-induced diabetes model MEPG (200 and 400 mg/kg, p.o.) and VAD (10, 25, and 50 mg/kg, p.o.) have showed significant and dose dependent antidiabetic activity by maintaining the blood glucose levels within the normal limits. Inline with the biochemical findings histopathology of MEPG (200 and 400 mg/kg, p.o.), VAD (10, 25, and 50 mg/kg, p.o.), and glibenclamide (10 mg/kg, p.o.) treated animals showed significant protection against alloxan-induced pancreatic tissue damage. These findings suggest that MEPG and VAD possess significant antidiabetic activity in both in vitro and in vivo models.

Blood sugar lowering effect of Coccinia grandis (L.) J. Voigt: path for a new drug for diabetes mellitus

Background. Role of herbs in the management and control of diabetes has emerged fast over the years. We assessed the efficacy of Coccinia grandis (locally known as Ken, Kovakka) leaves as a hypoglycemic agent. Methods. Double-blind phase I clinical trial was conducted at the general hospital and a private hospital in Matara in August 2009. All the participants were given a common meal for dinner, and they maintained a 10-hour fasting period. Sixty-one healthy volunteers were given a meal containing 20 g of leaves of Coccinia grandis which was mixed with a measured amount of scraped coconut and table salt for breakfast, and other 61 were given the placebo meal which also contained scraped coconut and salt. Glucose tolerance test was performed blindly for the two groups. Mixed factorial design analysis of variance and student's t-test were applied. Results. Overall blood sugar levels of the experimental group were also significantly lower than those of the control group (F(1,117) 5.56, P < 0.05). Increase in the blood sugar levels from fasting to one hour (F(1,117) 6.77, P < 0.05) and two hours (F(1,117) 5.28, P < 0.05) postprandially was statistically significant for participants who were in the control group than those of in the experimental group. The mean difference of postprandial blood sugar levels (mg/dL) after one hour (20.2, 95% confidence interval, 4.81 to 35.5) and two hours (11.46, 95% confidence interval; 1.03 to 21.9) was statistically significant between the two groups. Conclusions. Coccinia grandis has a blood sugar lowering effect. However further studies are needed to validate our findings.