Hypoglycemic, Hypolipidemic, Renal Protective and Antioxidant Activity of Annona muricata in Streptozotocin-Induced Diabetic Rats

Annona muricata, an herbal plant commonly used in traditional medicine to manage numerous diseases, diabetes as other diseases could be managed with herbal medicine. This study was designed to be investigated the antidiabetic, hypolipidemic, renal protective, and antioxidant effects of aqueous extracts of Annona muricata as used alone or combined with metformin in streptozotocin (STZ)-induced diabetic rats. Methods: the study was involved twenty adult Wister albino rats in four groups (five rats in each) and designated as groups, control group (1), and experimental groups (2, 3, 4). Diabetes was induced in experimental groups by 60 mg/kg intravenous streptozotocin injection. Group 2: serves as a diabetic control group, Group 3: diabetic rats treated with oral administration of 100 mg/kg of Annona muricata aqueous extract, Group 4: diabetic rats treated with combination (100 mg/kg aqueous extract of Annona muricata + 50 mg/kg metformin). The treatment continuous daily for 4 weeks to determine the levels of blood glucose and biochemical analysis. Result: aqueous extract of Annona muricata was reduced the serum glucose level effectively in streptozotocin-induced diabetic rats, by 48% and 55% after 28 consecutive days of treatment when used alone and with metformin, respectively. These compared to the preliminary values and the reduction was statistically significant compared to a diabetic control group. Daily oral administration of 100 mg/kg aqueous extract of Annona muricata for 4 weeks to streptozotocin-induced diabetic rats significantly reduced the level of total cholesterol, urea, creatinine, and MDA, whereas the reduction was non-significant in triglyceride and VLDL-cholesterol levels as compared to the non-treated diabetic group. However, the reduction is more significant in streptozotocin-induced diabetes rats that were treated with a combination of Annona muricata and metformin when compared to the diabetic control group. Conclusion: Aqueous extracts of Annona muricata have anti-diabetic action through their hypoglycemic, hypolipidemic, renal protective, and antioxidant effects in streptozotocin-induced diabetic rats. Thus, can be used alone or with anti-hyperglycemic drugs as metformin in the management of DM. The combination is preferred in severe hyperglycemic cases with more hypoglycemic effect requirements.

Effects of Silymarin on Blood Glucose Concentration, Hepatic Histopathological Changes and FOXA2 and FOXA3 Gene Expression in Streptozotocin-Induced Diabetic Male Wistar Rats

Since the liver is among the primary organs susceptible to the effects of hyperglycaemia, diabetes mellitus (DM) could be a risk factor for the development and progression of liver damage. In present study, since no side-effects from the herbal medicine have been reported, the effect of silymarin on blood glucose concentration, hepatic histopathological changes and FOXA2 and FOXA3 gene expression, which are key genes in liver regeneration, was investigated. In this fundamental with experimental approach study, 40 male Wistar rats weighing 180-220 g were used. Rats were kept under the standard conditions of temperature of 20-22°C and humidity of 50% and consecutive 12-hour periods of light and darkness. Rats were randomly divided into five different groups (n=8 each), including healthy control rats, diabetic control rats, diabetic rats receiving silymarin (50, 100 and 150 mg/kg). Diabetes was induced by injecting streptozotocin (50 mg/kg B.W., i.p.). For 4 weeks silymarin groups received the drug once every three days through gavage and fasting blood glucose concentration measured once every 10 days. At the end of a month experiment, livers were harvested for hepatic histopathological and FOXA2 and FOXA3 gene expression changes analysis. In the diabetic rats treated with silymarin (50, 100 and 150 mg/kg), by comparison with the diabetic control group (p<0.05), glucose levels decreased significantly. Moreover, FOXA2 and FOXA3 expression in diabetic groups treated with silymarin significantly increased compared to diabetic control group (p<0.05). Hepatic histopathological changes were improved in the treated groups.The present study indicates that silymarin significantly decreased blood glucose concentration and increased the FOXA2 and FOXA3 gene products level. Hence, silymarin is able to improve some of the symptoms associated with diabetes and possesses hepatoprotective effects in streptozotocin-induced diabetic rats.

ANTIDIABETIC AND ANTIHYPERLIPIDAEMIC EFFECTS OF THE ETHANOL EXTRACT OF THE LEAVES AND STEM OF CISSUS GRACILLIS (GULL ET PERR) (VITACEAE)

Objectives: This study investigated the antidiabetic and antihyperlipidemic potential of the ethanol extract of the leaves and stem of Cissus gracillis on alloxan monohydrate-induced diabetic albino rats. Methods: Preliminary phytochemical screening and acute toxicity were carried out. Animals were assigned into seven groups of five rats each. Groups A and B were administered 10 mg/kg each of glibenclamide and atorvastatin respectively, C, D, and E were given 125, 250 and 500 mg/kg of ethanol extract of C. gracillis, respectively, daily for 21 days through oral gavage, group F was diabetic but untreated (diabetic control group), while group G was non-diabetic and untreated which served as the control group. Results: Phytochemical screening revealed the presence of steroids/triterpenoids and carbohydrates. LD50 was above 5000 mg/kg. The extract at 500 mg/kg showed a statistically significant (p<0.05) decrease in blood glucose level when compared with the glibenclamide group on day 21. However, gradual non- significant reduction in blood glucose levels were observed in the extract treated groups on the 7th, 14th, and 21st days of treatment. The administration of ethanol extract of C. gracillis to alloxan-induced diabetic rats produced a decrease in total cholesterol, triglycerides, and low-density lipoproteins comparable to glibenclamide and atorvastatin. Conclusion: The ethanol extract of the leaves and stem of C. gracillis possess a mildly significant antidiabetic and antihyperlipidemic activity.

Evaluation of Antidiabetic Activity of Polyherbal Formulation “Vasant Kusumakar Ras” on Alloxan-induced and Dexamethasone-induced Diabetic Rats

Aim: The current study observed the antidiabetic effect of Vasant Kusumakar Ras, an Ayurvedic polyherbal formulation, in alloxan-induced and dexamethasone-induced diabetic rats. Materials and Methods: Alloxan (120 mg/kg, i.p.) and dexamethasone sodium phosphate (5 mg/kg, i.p.) were used to induce diabetes in rats. The oral antidiabetic activity of Vasant Kusumakar Ras was evaluated by single doses of Vasant Kusumakar Ras (400 and 600 mg/kg, p.o.) in albino rats during a 10-day treatment period, with the effect of the Vasant Kusumakar Ras on blood glucose levels and serum lipid parameters measured on 0, 7th, and 11th day. Glibenclamide (5 mg/kg, p.o.) was used as the reference drug. Results: In alloxan-induced diabetic rats, the elevated levels of blood glucose significantly (p < 0.05) decreased after oral administration of Vasant Kusumakar Ras (400 mg/kg and 600 mg/kg), and Glibenclamide (5 mg/kg). When compared to the diabetic control group, treatment with Vasant Kusumakar Ras and Glibenclamide for 10 days reduced total cholesterol (TC) significantly (p < 0.001). Treatment with Vasant Kusumakar Ras and Glibenclamide for 10 days, significantly (p < 0.001) decreased low-density lipoprotein (LDL) level when compared to the diabetic control group. In dexamethasone-induced diabetic rats, all rats given with dexamethasone and Vasant Kusumakar Ras (400 mg/kg and 600 mg/kg) showed a significant (p < 0.05) decrease in the level of blood glucose when compared with diabetic control rats. The rats treated with dexamethasone and Glibenclamide showed a significant (p < 0.05) decrease in blood glucose level when compared to diabetic control rats. When compared to the diabetic control group, treatment with Vasant Kusumakar Ras and Glibenclamide (5 mg/kg) for 10 days reduced TC significantly (p < 0.001). Treatment with Vasant Kusumakar Ras and Glibenclamide for 10 days, significantly (p < 0.001) decreased LDL level when compared to the diabetic control group. Conclusion: Vasant Kusumakar Ras was shown to have significant antidiabetic activity comparable to that of glibenclamide and it also improves the lipid metabolism in both alloxan-induced and dexamethasone-induced diabetic rats.

Impact of PCSK9 Immunization on Glycemic Indices in Diabetic Rats

Background and Aim. The impact of Proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibition on glycemic indices in diabetes mellitus remains far from clear. We explored the effects of PCSK9 inhibition on glycemic indices in the diabetes rat model. Methods. To prepare the anti-PCSK9 vaccine, a peptide construct called Immunogenic Fused PCSK9-Tetanus (IFPT) was linked to the surface of nanoliposome carriers. Healthy rats received four subcutaneous injections of the vaccine at biweekly intervals. Two weeks after the last vaccination, anti-PCSK9 antibody titers, PCSK9 targeting, and inhibition of PCSK9–low-density lipoprotein receptor (LDLR) interaction were evaluated. After verification of antibody generation, the immunized rats were intraperitoneally treated with a single dose (45 mg/kg) of streptozotocin (STZ) to induce diabetes mellitus. The levels of fasting blood glucose (FBG) were measured, and the oral glucose tolerance test (OGTT) as well as the insulin tolerance test (ITT) were carried out to assess glycemic status. At the end of the study, the total cholesterol, low-density lipoprotein cholesterol (LDL-C), triglyceride, and high-density lipoprotein cholesterol concentrations were assayed. Histopathology examination of the liver and pancreas was also performed using the hematoxylin-eosin staining method. Results. The prepared nanoliposomal vaccine could strongly induce anti-PCSK9 antibodies in the vaccinated rats. Within one week following the STZ injection, the FBG level was lower in the vaccinated group vs. diabetic control group (49% ( − 171.7 ± 35 mg / dL , p < 0.001 )). In the OGTT, the injected rats showed improved glucose tolerance as reflected by the reduction of blood glucose levels over 180 min, compared with the diabetic controls. Moreover, the ITT demonstrated that, after the insulin injection, blood glucose concentration declined by 49.3% in the vaccinated group vs. diabetic control group. Expectedly, the vaccinated rats exhibited lower (-26.65%, p = 0.03 ) plasma LDL-C levels compared with the diabetic controls. Histopathology examination of pancreas tissue demonstrated that the pancreatic islets of the vaccinated rats had a slight decline in the population of β-cells and few α-cells. Normal liver histology was also observed in the vaccinated rats. Conclusion. PCSK9 inhibition through the liposomal IFPT vaccine can improve the glucose and insulin tolerance impairments as well as the lipid profile in diabetes.

Beneficial Hypoglycemic, Hypolipidemic Effects of Aerial Branches and Roots Extract of Eryngium caeruleum M. Bieb on Streptozotocin-Induced Diabetes Model in Rats

Eryngium caeruleum (Apiacea) is native to the northern forests of Iran. The anti-diabetic effect of other species of the genus Eryngium has already been reported in previous studies. In this study, the anti-diabetic effect of this extract on animal blood lipid factors was investigated. Hydroalcoholic extract was obtained from different parts of the plant, including roots, leaves, and aerial branches with fruits were prepared by maceration with 70% ethanol. Oral acute toxicity of the extracts was assayed in different doses of 2000, 4000, and 8000 mg/kg in rats. To induce diabetes in the studied animals, 60-70 mg/kg of streptozotocin (STZ) was injected intraperitoneally (IP). For the purpose of this study, 72 male Wistar rats were randomly divided into different groups of normal, diabetic, and positive controls (metformin 500 mg/kg) as well as 9 diabetic groups that orally received 200, 400, and 800 mg/kg of extracts. The effects of the treatment with extracts for a 14-day period were investigated on weight, blood glucose, and lipid profile. By comparing the control groups with the groups of hydroalcoholic extracts of E. caeruleum showed that the most effective sample on weight gain and also on reducing blood glucose was the group receiving 800 mg/kg of the aerial branches extract (P < 0.01 and P < 0.001, respectively) after 14 days. As well, the most effective sample on lowering the blood lipid factors was the hydroalcoholic extract of the root of E. coareleum with a dose of 200 mg/kg, which showed a significant effect on lowering total cholesterol in diabetic rats compared to the diabetic controls (P < 0.05). Hydroalcoholic extract of leaves with 200 mg/kg also showed a better effect on lowering the LDL and VLDL levels compared to the diabetic control group (P < 0.001). The results of pancreatic histology in the samples showed that the extracts of the aerial branch and root (800 mg/kg) had significant effects on the regeneration of the islets of Langerhans compared to the diabetic control group. In conclusion, E. caeruleum could significantly improve glycemic and lipid profiles in diabetic rats.

Evaluation of the solubility of 11-keto-β-boswellic acid and its histological effect on the diabetic mice liver using a novel technique

Background and Aim: The literature is scant on the effect of 11-keto-β-boswellic acid (KBA) on the liver of diabetes-induced mice. This study was designed to develop a rapid, sensitive, accurate, and inexpensive detection technique for evaluating the solubility of KBA obtained from the gum resin of Omani frankincense (Boswellia sacra) in the liver of streptozotocin-induced diabetic mice using Fourier transform infrared (FTIR) reflectance spectroscopy coupled with principal components analysis (PCA). It also aimed to investigate the effect of KBA on histological changes in the hepatocytes of diabetic mice. Materials and Methods: Eighteen mice were assigned to the healthy control group, the diabetic control group, or the KBA-treated diabetic group. Liver tissue samples from all groups were scanned using an FTIR reflectance spectrophotometer in reflection mode. FTIR reflectance spectra were collected in the wavenumber range of 400-4000 cm-1 using an attenuated total reflectance apparatus. Results: FTIR reflectance spectra were analyzed using PCA. The PCA score plot, which is an exploratory multivariate data set, revealed complete segregation among the three groups' liver samples based on changes in the variation of wavenumber position in the FTIR reflectance spectra, which indicated a clear effect of KBA solubility on treatments. Histological analysis showed an improvement in the liver tissues, with normal structures of hepatocytes exhibiting mild vacuolation in their cytoplasm. Conclusion: KBA improved the morphology of liver tissues in the diabetic mice and led to complete recovery of the damage observed in the diabetic control group. FTIR reflectance spectroscopy coupled with PCA could be deployed as a rapid, low-cost, and non-destructive detection method for evaluating treatment effects in diseased liver tissue based on the solubility of KBA.

Accelerative Wound-Healing Effect of Aqueous Anthocephalus Cadamba Leaf Extract in a Diabetic Rat Model

Impaired wound healing is a major concern in diabetic patients due to unregulated chronic hyperglycemia which further may lead to ulcer, gangrene, and its complications. The present study unveils the accelerative effect of aqueous Anthocephalus cadamba leaf extract on wound healing in diabetic rats. Diabetes was induced in 30 Sprague Dawley female rats by using streptozotocin (except control group I) at the dose of 60 mg/kg intraperitoneally. Diabetic rats were randomized in 3 groups viz. diabetic control group (II), diabetes + Kadam plant leaf extract group (III), and diabetes + 5% povidone–iodine solution group (IV). Surgically sterile wound of 1.77 cm2 was created on the dorsal area of anaesthetized rats. The experimental parameters were assessed by hematobiochemical, histopathological, and western blot techniques. The A cadamba extract treatment group (III) (D + KPLE) showed a significant increase in the percentage of wound closure (82%) at day 21 as compared to the diabetic control group (42%), nondiabetic control group (I) (49%), and povidone–iodine treatment group (75%) group (IV). The findings of the present study suggest that the (D + KPLE) group (III) exhibited marked epithelial regeneration, neovascularization, collagen deposition, and fibroblast proliferation along with higher expression of vascular endothelial growth factor as compared to the diabetic control group (II), which was confirmed by histopathological examination and western blot analysis. The present study suggests that the topical application of aqueous A cadamba leaf extract exhibits accelerative wound-healing properties in diabetic rats.

Methanol extract of Aruncus dioicus exerts antidiabetic effect via PCSK9/LDLR pathway

Purpose: To investigate the antidiabetic effect of methanol extract of Aruncus dioicus, and the underlying mechanism(s). Methods: Twenty-four adult female albino mice were randomly assigned to four groups of six mice each: normal control group, diabetic control group and two treatment groups. With the exception of normal control group, the diabetic control and treatment groups consisted of leptin receptor-deficient (db/db) type 2 diabetic mice. The diabetic control group was not treated, while the treatment groups received 200 or 400 mg/kg extract/day orally for 4 weeks. The effect of the extract on fasting blood glucose (FBG), proprotein convertase subtilisin/kexin type 9 (PCSK9), glycogen and lipid profiles were determined. The expressions of PCSK9, low-density lipoprotein receptor (LDL-R) and glucokinase (GCK) were determined in liver tissues using western blotting and real-time quantitative polymerase chain reaction (qRT-PCR). Results: Fasting blood glucose (FBG) was significantly and dose-dependently reduced in the treatment groups, relative to diabetic control group at different time-points (p < 0.05). Total cholesterol (TC), triacylglycerol (TG), low-density lipoprotein cholesterol (LDL-C) and high-density lipoprotein cholesterol (HDL-C) were significantly higher in the diabetic control group than in normal control group (p < 0.05). However, treatment with methanol extract of A. dioicus significantly and dose-dependently reversed the changes in the levels of these parameters (p < 0.05). The expressions of LDLR and GCK were significantly down-regulated in diabetic control group, when compared with normal control group, but their expressions were significantly dose-dependently upregulated in the treatment groups (p < 0.05). Treatment with the extract significantly and dose-dependently down-regulated PCSK9 expression (p < 0.05). Liver injury characterized by large distended lipid droplets and fat accumulation was seen in diabetic mice, but treatment with methanol extract of A. dioicus significantly reversed the histopathological changes induced by DM. Conclusion: These results indicate that the antidiabetic effect of methanol extract of A. dioicus is exerted via a mechanism involving PCSK9/LDLR pathway.

Tribulus terrestris Efficacy and Safety Concerns in Diabetes and Erectile Dysfunction, Assessed in an Experimental Model

The present project aims to evaluate Tribulus terrestris (TT) extracts by addressing various possible mechanisms of action in order to see whether the use of TT supplements in diabetes and diabetes complications is justified. Diabetic rats were divided into three groups: diabetic control group, TT extract with low protodioscin content group (TT-LPC) and TT extract with high protodioscin content group (TT-HPC). After twelve weeks of treatment, fasting blood glucose, insulin, LH, FSH and testosterone levels were measured. Both TT preparations reduced elevated blood glucose level. Insulin and luteinizing hormone levels were not significantly different compared with the control group; however, the FSH and testosterone levels were significantly higher in the TT-HPC group compared with the diabetic control group. The testosterone level is correlated in part with the protodioscin concentration in extracts and is probably mediated through an FSH-linked pathway.