Impaired antioxidant status in diabetic rat liver. Effect of vanadate

Sodium orthovanadate exhibits anti-angiogenic, antiapoptotic and blood glucose-lowering effect on colon cancer associated with diabetes

BACKGROUND

The presence of type 2 diabetes mellitus increases the risk of developing the colon cancer. The main objective of this study was to determine the role of sodium orthovanadate (SOV) in colon cancer associated with diabetes mellitus by targeting the competitive inhibition of PTP1B.

METHODS

For in vivo study, high fat diet with low dose streptozotocin model was used for inducing the diabetes mellitus. Colon cancer was induced by injecting 1,2-dimethylhydrazine (25 mg/kg, sc) twice a week. TNM staging and immunohistochemistry (IHC) was carried out for colon cancer tissues. In vitro studies like MTT assay, clonogenic assay, rhodamine-123 dye assay and annexin V-FITC assay using flow cytometry were performed on HCT-116 cell line. CAM assay was performed to examine the anti-angiogenic effect of the drug.

RESULTS

Sodium orthovanadate reduces the blood glucose level and tumor parameters in the animals. In vitro studies revealed that SOV decreased cell proliferation dose dependently. In addition, SOV induced apoptosis as depicted from rhodamine-123 dye assay and annexin V-FITC assay using flow cytometry as well as p53 IHC staining. SOV showed reduced angiogenesis effect on eggs which was depicted from CAM assay and also from CD34 and E-cadherin IHC staining.

CONCLUSIONS

Our data suggest that SOV exhibits protective role in colon cancer associated with diabetes mellitus. SOV exhibits anti-proliferative, anti-angiogenic and apoptotic inducing effects hence can be considered for therapeutic switching in diabetic colon cancer.

Effect of Bitter-leaf (Vernonia amygdalina) Flavored Non-alcoholic Wheat Beer (NAWB) on, Insulin and GLUT-2 expression in Pancreas of High fat diet/Streptozotocin (HFD/STZ) Induced Diabetic Wistar Rats

Purpose

In the management of type 2 diabetes (T2D), dietary intervention has been proposed to be highly effective. This study, therefore, investigated the effect of bitter leaf-flavored non-alcoholic wheat beer (NAWB) on insulin secretion and GLUT-2 expression in the pancreas of STZ-induced diabetic rats.

Methods

In this study, the rats received a single intraperitoneal injection (i.p.) of STZ (35 mg/kg) after being fed a high-fat diet for 14 days to induce T2D. The rats were treated with bitter leaf flavored NAWB samples (100%HP- Hops only, 100%BL-Bitter leaf only, 75,25BL- 75% Hops, 25% Bitter Leaf, 50:50BL- 50% Hops:50% Bitter Leaf, and 25:75BL-25%Hops:75% Bitter Leaf) and Acarbose for 14 days. The superoxide dismutase, catalase, and glutathione peroxidase activity were also determined.

Results

The results from this study showed a correlation between GLUT-2 and Insulin expression. There was an upregulation of Insulin as GLUT-2 expression was upregulated. Furthermore, the treated groups showed better antioxidant activity when compared with the diabetic control.

Conclusion

Bitter leaf-flavored NAWB might thus be a good dietary intervention for type 2 diabetics.

Effect of Cyberlindnera jadinii supplementation on growth performance, serum immunity, antioxidant status, and intestinal health in winter fur-growing raccoon dogs (Nyctereutes procyonoides)

Introduction

This study aimed to investigate the effects of Cyberlindnera jadinii supplementation on the growth performance, nutrient utilization, serum biochemistry, immunity, antioxidant status, and intestinal microbiota of raccoon dogs during the winter fur-growing period.

Methods

Forty-five 135 (±5) day-old male raccoon dogs were randomly assigned to three dietary groups supplemented with 0 (group N), 1 × 10⁹ (group L) and 5 × 10⁹ CFU/g (group H) Cyberlindnera jadinii, with 15 raccoon dogs per group.

Results

The results showed that Cyberlindnera jadinii in groups L and H improved average daily gain (ADG) and decreased feed-to-weight ratio (F/G) (P < 0.05). No significant difference was found in nutrient digestibility and nitrogen metabolism among the three groups (P > 0.05). Compared with group N, serum glucose levels were lower in groups L and H (P < 0.05). The levels of serum immunoglobulins A and G in group L were higher than those in the other two groups (P < 0.05), and the levels of serum immunoglobulins A and M in group H were higher than those in group N (P < 0.05). Supplementation with Cyberlindnera jadinii in groups L and H increased serum superoxide dismutase activity, and the total antioxidant capacity in group H increased compared with group N (P < 0.05). The phyla Bacteroidetes and Firmicutes were dominant in raccoon dogs. The results of principal coordinate analysis (PCoA) showed that the composition of microbiota in the three groups changed significantly (P < 0.05). The relative abundance of Campylobacterota was increased in the H group compared to the N and L groups (P < 0.05). The relative abundance of Sarcina was increased in group L compared with the other two groups (P < 0.05), while the relative abundance of Subdoligranulum and Blautia were decreased in group H compared with the other two groups (P < 0.05). Also, the relative abundance of Prevotella, Sutterella and Catenibacterium was higher in group L (P < 0.05) compared with group H.

Discussion

In conclusion, dietary supplementation with Cyberlindnera jadinii improved growth performance, antioxidant activity, immune status, and improved intestinal microbiota in winter fur-growing raccoon dogs. Among the concentrations tested, 1 × 10⁹ CFU/g was the most effective level of supplementation.

Vanadium and biomarkers of inflammation and oxidative stress in diabetes: A systematic review of animal studies

Background: Oxidative stress has a significant role in the commencement and development of hyperglycemia. Vanadium, as a transitional metal with redox properties, enters the redox process, produces free radicals, and distracts the pro-antioxidant balance. The present animal systematic review aimed to assess the effect of vanadium supplementation on inflammation and oxidative stress biomarkers in diabetes-induced animals. Methods: A systematic search was conducted using the PubMed, Scopus, and web of science databases from 1990 to 2021, according to the inclusion and exclusion criteria. The search strategy was based on the guidelines for systematic review of animal experiments and Preferred Reporting Items for Systematic Reviews (PRISMA). Criteria for eligibility were animal-based studies, evaluating the therapeutic effects of vanadium on inflammatory and oxidative stress biomarkers in diabetes. The Systematic Review Centre for Laboratory Animal Experimentation (SYRCLE) tool was used for assessing the methodological quality of included studies. Results: In the present study, 341 articles were evaluated out of which 42 studies were eligible for inclusion. The majority of the studies confirmed the advantageous properties of vanadium on inflammatory and oxidative stress biomarkers. A minor risk of bias was reported, based on the SYRCLE's tool. Conclusion: According to the findings, well-designed clinical trials are warranted to assess the long-lasting effects of various vanadium compounds on inflammatory and oxidative stress biomarkers.

The effects of a new antidiabetic glycinium [(pyridine-2, 6-dicarboxylato) oxovanadate (V)] complex in high-fat diet of streptozotocin-induced diabetic rats

OBJECTIVE

The present study aimed to evaluate the antidiabetic effects of glycinium [(pyridine-2, 6-dicarboxylato) oxovanadate (V)] complex in type 2 diabetes rat model.

MATERIALS AND METHODS

Rats were allocated into 6 groups. Group I, nondiabetic rats; Group II, diabetic rats; Group III, diabetic rats receiving an intraperitoneal (i.p.) injection of metformin (45 mg/kg); Groups IV, V and VI were diabetic rats receiving i.p. injection of 5, 10, and 20 mg/kg of the complex for 3 weeks, respectively. Fasting blood glucose (FBG), insulin, liver enzymes, malondialdehyde (MDA), total antioxidant capacity (TAC), lipid profile, and HbA1c were measured.

RESULTS

AST, ALT and GGT activities and MDA levels were increased, while TAC was decreased in diabetic animals. Treatment of diabetic rats improved the HOMA-IR and returned HbA1c level to the normal value as well as elevated TAC and reduced MDA level.

CONCLUSION

We found that the complex possesses antidiabetic properties in experimental diabetes.

Response of Cytoprotective and Detoxifying Proteins to Vanadate and/or Magnesium in the Rat Liver: The Nrf2-Keap1 System

Oxidative stress (OS) is a mechanism underlying metal-induced toxicity. As a redox-active element, vanadium (V) can act as a strong prooxidant and generate OS at certain levels. It can also attenuate the antioxidant barrier and intensify lipid peroxidation (LPO). The prooxidant potential of V reflected in enhanced LPO, demonstrated by us previously in the rat liver, prompted us to analyze the response of the nuclear factor erythroid-derived 2-related factor 2/Kelch-like ECH-associated protein 1 (Nrf2-Keap1) system involved in cellular regulation of OS to administration of sodium metavanadate (SMV, 0.125 mg V/mL) and/or magnesium sulfate (MS, 0.06 mg Mg/mL). The levels of some Nrf2-dependent cytoprotective and detoxifying proteins, i.e., glutathione peroxidase (GPx), glutathione reductase (GR), glutathione S-transferase (GST), glutamate cysteine ligase catalytic subunit (GCLC), glutathione synthetase (GSS), NAD(P) H dehydrogenase quinone 1 (NQO1), UDP-glucumno-syltransferase 1 (UGT1), and heme oxygenase 1 (HO-1); glutathione (GSH); metallothionein (MT1); and glutamate-cysteine ligase (GCL) mRNA were measured. We also focused on the V-Mg interactive effects and trends toward interactive action as well as relationships between the examined indices. The elevated levels of Nrf2, GCL mRNA, and GCL catalytic subunit (GCLC) confirm OS in response to SMV and point to the capacity to synthesize GSH. The results also suggest a limitation of the second step in GSH synthesis reflected by the unchanged glutathione synthetase (GSS) and GSH levels. The positive correlations between certain cytoprotective/detoxifying proteins (which showed increasing trends during the SMV and/or MS administration, compared to the control) and between them and malondialdehyde (MDA), the hepatic V concentration/total content, and/or V dose (discussed by us previously) point to cooperation between the components of antioxidant defense in the conditions of the hepatic V accumulation and SMV-induced LPO intensification. The V-Mg interactive effect and trend are involved in changes in Nrf2 and UGT1, respectively. The p62 protein has to be determined in the context of potential inhibition of degradation of Keap1, which showed a visible upward trend, in comparison with the control. The impact of Mg on MT1 deserves further exploration.

Therapeutic role of Azadirachta indica leaves ethanolic extract against diabetic nephropathy in rats neonatally induced by streptozotocin

Diabetic nephropathy (DN) is manifested by chronic loss of renal function due to damage of glomeruli and renal tubules. Therefore, this study is mainly designed to evaluate the therapeutic role of Azadiracta indica (neem) leaves extract as a novel approach for treatment of DN in rats neonatally induced by streptozotocin (STZ). For this study, 40 offspring were selected after parturition and categorized into four groups (n = 10). Group1: control group, group 2: neem leaves extract supplemented group, group 3: diabetic group that injected with a single dose of STZ and group 4: diabetic group treated with neem extract. The results revealed deleterious histological and ultrstructural changes in the renal tissues of diabetic rats. Such changes included atrophied glomeruli, dilated renal cortical tubules and scattered hemorrhage spots, thickening of glomerular basement membrane, expansion of mesangial matrix and pyknotic podocyte. Additionally, the proximal convoluted tubule and distal tubule showed cytoplasmic vacuolation, vacuolated mitochondria, scattered lipid droplets, lost microvilli and disrupted basal lamina and basal infoldings. Moreover, significant decreased levels of serum antioxidants (SOD&CAT) and significant increased levels of serum MDA, urea and creatinine were noticed in diabetic rats. Neem leaves extract successfully alleviated the histological and ultrastructural as well as biochemical changes induced by diabetes.

Combined treatment of sinapic acid and ellagic acid attenuates hyperglycemia in streptozotocin-induced diabetic rats

In the present study, we aimed to investigate the effect of individual and combined treatment of sinapic acid (SA) and ellagic acid (EA) in streptozotocin (STZ)-induced diabetic rats. Rats were divided into eight groups (n = 7): Normal Control, Diabetic Control, Diabetic + Sinapic Acid, Diabetic + Ellagic Acid, Diabetic + Sinapic Acid + Ellagic Acid, Sinapic Acid, Ellagic Acid and Sinapic Acid + Ellagic Acid. Diabetic groups were injected with a single dose of 50 mg/kg STZ intraperitoneally. Rats received 20 mg/kg/day SA and 50 mg/kg/day EA intragastrically for 28 days. The numerical density of immunopositive β-cells and volume density of pancreatic islets were calculated. Additionally, glucose and insulin levels in serum, MDA, GSH, and CAT levels of pancreatic tissue were measured. While serum glucose levels increased, serum insulin levels decreased in STZ-induced diabetic rats. But these changes in glucose and insulin were restored by individual and combined treatments of SA and EA. Also, individual and combined treatments of SA and EA increased insulin expression of β-cells in STZ-induced diabetic rats. Moreover, these compounds improved deteriorating oxidative stress parameters in STZ-induced diabetic rats. Our study indicates that SA and EA, especially their combined treatments, can be used as an antihyperglycemic agent in diabetes.

Exploring the Physiological Role of Transthyretin in Glucose Metabolism in the Liver

Transthyretin (TTR), a 55 kDa evolutionarily conserved protein, presents altered levels in several conditions, including malnutrition, inflammation, diabetes, and Alzheimer’s Disease. It has been shown that TTR is involved in several functions, such as insulin release from pancreatic β-cells, recovery of blood glucose and glucagon levels of the islets of Langerhans, food intake, and body weight. Here, the role of TTR in hepatic glucose metabolism was explored by studying the levels of glucose in mice with different TTR genetic backgrounds, namely with two copies of the TTR gene, TTR+/+; with only one copy, TTR+/−; and without TTR, TTR−/−. Results showed that TTR haploinsufficiency (TTR+/−) leads to higher glucose in both plasma and in primary hepatocyte culture media and lower expression of the influx glucose transporters, GLUT1, GLUT3, and GLUT4. Further, we showed that TTR haploinsufficiency decreases pyruvate kinase M type (PKM) levels in mice livers, by qRT-PCR, but it does not affect the hepatic production of the studied metabolites, as determined by 1H NMR. Finally, we demonstrated that TTR increases mitochondrial density in HepG2 cells and that TTR insufficiency triggers a higher degree of oxidative phosphorylation in the liver. Altogether, these results indicate that TTR contributes to the homeostasis of glucose by regulating the levels of glucose transporters and PKM enzyme and by protecting against mitochondrial oxidative stress.

Vanadium and Oxidative Stress Markers - In Vivo Model: A Review

This review article is an attempt to summarize the current state of knowledge of the impact of Vanadium (V) on Oxidative Stress (OS) markers in vivo. It shows the results of our studies and studies conducted by other researchers on the influence of different V compounds on the level of selected Reactive Oxygen Species (ROS)/Free Radicals (FRs), markers of Lipid peroxidation (LPO), as well as enzymatic and non-enzymatic antioxidants. It also presents the impact of ROS/peroxides on the activity of antioxidant enzymes modulated by V and illustrates the mechanisms of the inactivation thereof caused by this metal and reactive oxygen metabolites. It also focuses on the mechanisms of interaction of V with some nonenzymatic compounds of the antioxidative system. Furthermore, we review the routes of generation of oxygen-derived FRs and non-radical oxygen derivatives (in which V is involved) as well as the consequences of FR-mediated LPO (induced by this metal) together with the negative/ positive effects of LPO products. A brief description of the localization and function of some antioxidant enzymes and low-molecular-weight antioxidants, which are able to form complexes with V and play a crucial role in the metabolism of this element, is presented as well. The report also shows the OS historical background and OS markers (determined in animals under V treatment) on a timeline, collects data on interactions of V with one of the elements with antioxidant potential, and highlights the necessity and desirability of conducting studies of mutual interactions between V and antioxidant elements.

Ethyl Vanillin Protects against Kidney Injury in Diabetic Nephropathy by Inhibiting Oxidative Stress and Apoptosis

Diabetes-induced oxidative stress and apoptosis is regarded as a critical role in the pathogenesis of diabetic nephropathy (DN). Treating diabetes-induced kidney damage and renal dysfunction has been thought a promising therapeutic option to attenuate the development and progression of DN. In this study, we investigated the renoprotective effect of ethyl vanillin (EVA), an active analogue of vanillin isolated from vanilla beans, on streptozotocin- (STZ-) induced rat renal injury model and high glucose-induced NRK-52E cell model. The EVA treatment could strongly improve the deterioration of renal function and kidney cell apoptosis in vivo and in vitro. Moreover, treating with EVA significantly decreased the level of MDA and reactive oxygen species (ROS) and stabilized antioxidant enzyme system in response to oxidative stress by enhancing the activity of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) in vivo and in vitro. Furthermore, EVA also markedly suppressed cleaved caspase-3, Bax, and nuclear transcription factor erythroid 2-related factor (Nrf2) expression in STZ-induced rats. Therefore, these results of our investigation provided that EVA might protect against kidney injury in DN by inhibiting oxidative stress and cell apoptosis.

Crocin (active constituent of saffron) improves CCl4-induced liver damage by modulating oxidative stress in rats

Background

CCl4 is a widely used xenobiotic for the purpose of causing liver damage in experimental studies. In this study, we aimed to reveal the effects of crocin on liver injury caused by CCl4 via free radical scavenging properties.

Materials and methods

Animals were divided into five groups of 10: control; corn oil; crocin; CCl4; CCl4 + crocin. Tissue samples were carefully removed and separated for biochemical and histological investigations.

Results

CCl4 administration led to significant increases in MDA, SOD, CAT and TOS in liver tissue, and AST, ALT and ALP levels in plasma (p < 0.05). In addition, CCl4 caused significant decreases in GSH and TAS (p < 0.05). When animals were treated with crocin, high MDA, SOD, CAT, TOS levels, and AST and ALP activities decreased and GSH and TAS levels increased. Control group exhibited normal histological appearance; however extensive necrosis areas were detected in the CCl4 group. In the CCl4 + crocin group, pathological changes were markedly decreased and the appearance of liver tissue was almost similar to the control groups.

Conclusion

Our results showed that crocin suppresses oxidative stress with antioxidant properties and has a protective effect on tissue damage caused by CCl4.

Effectiveness of Genistein Supplementation on Metabolic Factors and Antioxidant Status in Postmenopausal Women With Type 2 Diabetes Mellitus

OBJECTIVES

The risk of type 2 diabetes mellitus (T2DM) increases in women after menopause. Genistein is known to modulate metabolic pathways. The aim of this study was to investigate the effects of genistein supplementation on metabolic parameters, oxidative stress and obesity values in postmenopausal women with T2DM.

METHODS

This randomized, double-blind, placebo-controlled clinical trial was conducted on 54 postmenopausal women 47 to 69 years of age with T2DM. The genistein group (n=28) was given 2 genistein capsules daily for 12 weeks. Each capsule contained 54 mg genistein. The placebo group (n=26) received 2 placebo capsules daily for the same period. Fasting blood samples, anthropometric measurements, dietary intakes and physical activity levels of subjects were collected at baseline and at the end of the trial. Data were analyzed by independent t test, paired t test and analysis of covariance.

RESULTS

Genistein supplementation significantly reduced serum levels of fasting blood glucose (FBS), glycated hemoglobin (A1C), serum triglyceride (TG) and malondialdehyde (MDA) and increased total antioxidant capacity (TAC) compared with the placebo group at the end of the study (p<0.05 for all). Serum high-density lipoprotein cholesterol and quantitative insulin sensitivity check index significantly increased within the genistein group. Changes in anthropometric indexes and other variables were not significant in any of the groups.

CONCLUSIONS

Genistein administration improved FBS, A1C, serum TG, TAC and MDA in postmenopausal women with T2DM and may be useful in the control of metabolic status and oxidative stress in these subjects.

Antihyperglycemic and antihyperlipidemic activities of Nannochloropsis oculata microalgae in Streptozotocin-induced diabetic rats

Background

It is well documented that biologically active components of microalgae can be utilized for treatment of different diseases. This study was conducted to evaluate the antihyperglycemic and antihyperlipidemic activities and weight control of Nannochloropsis oculata microalgae (NOM) in Streptozotocin-induced diabetic male rats.

Methods

Diabetes was induced by intraperitoneal administration of Streptozotocin (55 mg/kg). Healthy and diabetic rats were divided in to six groups. Healthy and diabetic rats orally received distilled water or NOM (10 and 20 mg/kg) for three weeks.

Results

Oral administration of NOM to diabetic rats significantly reduced the serum concentrations of glucose, cholesterol, triglycerides, LDL and increased the serum concentration of insulin and HDL-C (P<0.05). Treatment with NOM had no significant effect on blood parameters in healthy rats (P>0.05). Also, NOM maintained body weight in diabetic rats (P<0.05).

Conclusion

It can be concluded that NOM has antihyperglycemic and antihyperlipidemic activities in diabetic rats.

Beneficial effects of 6-shogaol on hyperglycemia, islet morphology and apoptosis in some tissues of streptozotocin-induced diabetic mice

BACKGROUND

Diabetes is characterized by hyperglycemia due to impaired insulin secretion and aberrant glucagon secretion resulting from changes in pancreatic islet cell function and/or mass. The aim of the present study was to investigate the effects of ginger on various tissues (i.e., pancreas, kidney, and liver) and insulin resistance in streptozotocin-induced diabetic mice. The pleasant aroma of ginger comes from the constituents present in its volatile oil, while its non-volatile pungent phytochemicals consist of gingerols, shogaols, and paradols.

METHODS

This research was conducted to determine the effects of 6-shogaol administration on blood glucose and insulin production in type 1 diabetic mice. Mice were intraperitoneally injected with shogaol at 5 or 10 mg/kg body weight. Untreated mice were injected with an equivalent volume of buffer, three times a week for 2 weeks. The animals were randomly divided into four experimental groups: control group mice (n = 3) were given an intraperitoneal (IP) injection of streptozotocin (STZ) vehicle (1 mL citrate buffer/100 g body weight) at day 1 and received an IP injection of 6-shogaol vehicle [1 mL buffer (0.5% DMSO, 10% Tween 20, and 89.5% PBS)/100 g body weight] every other day for 4 consecutive days.

RESULTS

6-Shogaol exhibited an antidiabetic effect by significantly decreased the level of blood glucose, body weight and attenuated the above pathological changes to the normal levels in the diabetic mice, and has effect against pancreas, kidney, liver damage in the diabetic mice. Since, 6-shogaol prevented the damage for STZ induced stress.

CONCLUSION

6-Shogaol can be used as a therapeutic agent for preventing complications in diabetic patients. Diabetic treatment consider the 6-shogaol as a pharmatheuticals or combination drug with herbal plant or others 6-shogaol may be a good therapeutic drug because it covers not only pancreatic β-cell but also liver and kidney. Ginger may be ideal because they contain a variety of pharmacological compounds with different known pharmacological actions.

Vanadium in Biosphere and Its Role in Biological Processes

Ultra-trace elements or occasionally beneficial elements (OBE) are the new categories of minerals including vanadium (V). The importance of V is attributed due to its multifaceted biological roles, i.e., glucose and lipid metabolism as an insulin-mimetic, antilipemic and a potent stress alleviating agent in diabetes when vanadium is administered at lower doses. It competes with iron for transferrin (binding site for transportation) and with lactoferrin as it is secreted in milk also. The intracellular enzyme protein tyrosine phosphatase, causing the dephosphorylation at beta subunit of the insulin receptor, is inhibited by vanadium, thus facilitating the uptake of glucose inside the cell but only in the presence of insulin. Vanadium could be useful as a potential immune-stimulating agent and also as an antiinflammatory therapeutic metallodrug targeting various diseases. Physiological state and dose of vanadium compounds hold importance in causing toxicity also. Research has been carried out mostly on laboratory animals but evidence for vanadium importance as a therapeutic agent are available in humans and large animals also. This review examines the potential biochemical and molecular role, possible kinetics and distribution, essentiality, immunity, and toxicity-related study of vanadium in a biological system.

Restorative potentiality of S-allylcysteine against diabetic nephropathy through attenuation of oxidative stress and inflammation in streptozotocin-nicotinamide-induced diabetic rats

AIM

In the present study, we evaluated the therapeutic potentiality of S-allylcysteine (SAC) in streptozotocin (STZ)-nicotinamide (NAD)-induced diabetic nephropathy (DN) in experimental rats.

METHODS

SAC was orally administered for 45 days to rats with STZ-NAD-induced DN; a metformin-treated group was included for comparison. Effect of SAC on body weight, organ weight, blood glucose, levels of insulin, glycated haemoglobin, and renal biochemical markers was determined. Body composition by total body electrical conductivity (TOBEC) and dual-X ray absorptiometry (DXA), kidney antioxidant analysis, real-time polymerase chain reaction, and western blot analysis of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), nuclear factor kappa B (NF-κB), interleukin (IL)-6, and tumor necrosis factor (TNF)-α; histopathological and scanning electron microscope (SEM) analysis of the kidneys were performed in both control and experimental rats.

RESULTS

SAC treatment showed significantly decreased levels of blood glucose, glycated haemoglobin, creatinine, albumin, AST, ALT, creatinine kinase, lactate dehydrogenase, and expressions of NF-κB, IL-6, and TNF-α compared with DN control rats. Furthermore, SAC administration to DN rats significantly improved body composition and antioxidant defense mechanism which was confirmed by the upregulation of mRNA and protein expressions of antioxidant genes.

CONCLUSIONS

Thus, SAC showed adequate therapeutic effect against DN by downregulation of inflammatory factors and attenuation of oxidative stress. Histological and SEM observations also indicated that SAC treatment notably reverses renal damage and protects the kidneys from hyperglycemia-mediated oxidative damage.

Diabetes Mellitus and Liver Surgery: The Effect of Diabetes on Oxidative Stress and Inflammation

Diabetes mellitus (DM) is a metabolic disorder characterized by hyperglycaemia and high morbidity worldwide. The detrimental effects of hyperglycaemia include an increase in the oxidative stress (OS) response and an enhanced inflammatory response. DM compromises the ability of the liver to regenerate and is particularly associated with poor prognosis after ischaemia-reperfusion (I/R) injury. Considering the growing need for knowledge of the impact of DM on the liver following a surgical procedure, this review aims to present recent publications addressing the effects of DM (hyperglycaemia) on OS and the inflammatory process, which play an essential role in I/R injury and impaired hepatic regeneration after liver surgery.

Evaluation of lipid peroxidation and antioxidant defense mechanisms in the bone of rats in conditions of separate and combined administration of vanadium (V) and magnesium (Mg)

The impact of vanadium (V) and magnesium (Mg) applied as sodium metavanadate (SMV, 0.125 mg V/ml) and magnesium sulfate (MS, 0.06 mg Mg/ml) on oxidative stress markers in bone of male Wistar rats was investigated. Some of them were also measured in the liver, e.g. l-ascorbic acid (hepatic L-AA). Additionally, relationships between selected indices determined in bone were examined. SMV alone (Group II) did not significantly alter the level of TBARS and the activity of SOD, compared with the control (Group I), but it slightly reduced the GR activity (by 13%) and the L-AA level (by 15.5%). It also markedly lowered the activity of CAT and GPx (by 34% and 29%), and to some degree elevated the activity of GST (by 16%) and the hepatic L-AA level (by 119%). MS alone (Group III) decreased the TBARS level (by 49%), slightly lowered the L-AA concentration (by 14%), and reduced the SOD, GPx, and GR activities (by 31%, 40%, and 28%), but did not change the activity of CAT, compared with the control. Additionally, it elevated the GST activity (by 56%) and the hepatic L-AA level (by 40%). In turn, the SMV + MS combination (Group IV) reduced the TBARS level (by 38%) and the SOD, CAT, GPx, and GR activities (by 61%, 58%, 72%, and 40%) but elevated the GST activity (by 66%), compared with the control. The activity of SOD and GPx in the rats in Group IV was also reduced, compared with Group II (by 61% and 61%) and Group III (by 44% and 54%). In turn, the activities of CAT and GR were decreased, compared with Group III (by 55%) and Group II (by 31%), and the L-AA level was lowered, in comparison with Groups II and III (by 53% and 54%). Further, the concentration of V in the bone of rats in Groups II and IV increased, whereas the concentration of Mg decreased, compared with Groups I and III, in which the V and Mg levels dropped and were not altered, respectively, compared with Group I. The total content of Fe in the bone of rats in Groups II and IV increased, compared with Group III, in which the total Fe content did not change, compared with Group I. In turn, the total bone Cu content significantly decreased in the rats in Groups III and IV, compared with Groups I and II, whereas the total Zn content and the Ca concentration did not change markedly. The results provided evidence that the concentration of V used as SMV did not enhance LPO in bone, whereas Mg, at the selected level, markedly reduced LPO in this tissue. On the other hand, both elements administered separately and in combination disrupted the antioxidant defense mechanisms and homeostasis of some metals in bone tissue, which consequently may have contributed to disturbances in the balance in the activities of osteoblastic and osteoclastic cells, and thereby negatively affected bone health.

Phytochemical characterization of the Vochysia rufa (Vochysiaceae) extract and its effects on oxidative stress in the pancreata of streptozotocin-induced diabetic rats

Aqueous extract of macerated Vochysia rufa stem bark has been commonly used in the treatment of diabetes. Therefore, we evaluated the antihyperglycemic and antioxidant effects of an extract of V. rufa on the pancreata of streptozotocin (STZ)-induced diabetic rats. Animals received one of the following treatments daily by oral gavage: water (diabetic-control), V. rufa extract (diabetic-V. rufa), or glibenclamide (diabetic-GBD). Total antioxidant capacity; levels of thiobarbituric acid reactive substances, reduced glutathione, and sulfhydryls; and superoxide dismutase, catalase, and glutathione peroxidase (GPx) activities were measured in the pancreas. Biochemical analysis of serum total cholesterol and fractions, triglycerides, creatinine, urea, acid uric, ALP, γ-GT, AST, and ALT was performed, and pancreatic β-cells positive for insulin were evaluated by immunohistochemistry. Rats treated with extract exhibited a decrease in fasting blood glucose compared with levels in diabetic control rats. GPx activity and sulfhydryl levels were significantly lower in diabetic-V. rufa rats compared with those of diabetic-control rats. V. rufa extract acted to normalize the biochemical alterations found in diabetic rats (diabetic-controls), as demonstrated by increases in urea, HDL, ALP, AST, and ALT. Reduction in blood glucose was independent of an increase in insulin. The V. rufa extract was found to be composed of free sugars (inositol, galactose, glucose, mannose, sucrose, arabinose, and ribose) as the main metabolites. Thus, aqueous extract of the stem bark of V. rufa is capable of reducing blood glucose, resulting in an antioxidant effect on the pancreatic tissue of STZ-diabetic rats.

Effect of melatonin versus vitamin D as antioxidant and Hepatoprotective agents in STZ-induced diabetic rats

Background

Diabetes mellitus (DM) is a serious chronic disease, with multiple complications including hepatopathy associated with imbalance of the oxidative status. The purpose of this study is to observe possible protective effects of vitamin-D and melatonin on glucose profile, antioxidant-oxidant status, lipid peroxidation, and histopathological protection of the liver in streptozotocin-induced diabetic rats.

Methods

Eighty three male albino rats were divided into nine groups as follows: G1 (n = 10) Normal control rats; G2 (n = 8) were normal rats treated with melatonin only; G3 (n = 10) were normal rats treated with vitamin D only; G4 (n = 9) were diabetic rats, which received no medications; G5 (n = 8) were diabetic rat treated with insulin only; G6 (n = 10) were diabetic rats treated with melatonin only; G7 (n = 9) were diabetic rats treated with melatonin and insulin; G8 (n = 9) were diabetic rats treated with vitamin D only; G9 (n = 10) were diabetic rats treated with vitamin D and insulin. Two months post treatment, blood was collected to measure: Fasting blood sugar (FBS), glycosylated hemoglobin (HbA1c), fructosamine (FA), total antioxidant capacity (TAC), malondialdahyde (MDA). livers were isolated for histopathological study.

Results

As compared to normal rats, our results demonstrate that glucose, fructosamine and HbA1c levels is increased in diabetic groups and declined to lesser levels in treated groups. TAC level of diabetic rats is not significantly changed. Vitamin D administration significantly increased TAC while it is not changed with melatonin either in treated or non-treated groups. The liver of diabetic rats shows only mild focal microvesicular fatty degeneration. The liver of diabetic rats treated with insulin shows degeneration of cell edema in the stroma. The liver of diabetic rats treated with melatonin with or without insulin, exhibited marked improvement. The liver of diabetic rats treated with vitamin D with or without insulin, shows degeneration of cells and edema in the stroma.

Conclusion

Our results demonstrated the beneficial antioxidant effect of vitamin D administration to normal and diabetic rats as compared to melatonin. Nevertheless, melatonin still shows more therapeutic effect on liver cell injury induced by induction of diabetes.

Effects of Ankaferd BloodStopper on dermal healing in diabetic rats

BACKGROUND/AIM

Diabetes mellitus inhibits wound-induced angiogenesis, impairs the wound healing process, and leads to the development of chronic wounds. Ankaferd BloodStopper (ABS) is a new and promising local haemostatic agent. Although the mechanism of ABS-mediated haemostasis is well established, little is known about the associated histological and biochemical tissue reactions. The aim of this study was to evaluate the effects of this new-generation local haemostatic agent on short-term soft-tissue healing in streptozotocin (STZ)-treated rats.

MATERIALS AND METHODS

The 24 Wistar albino rats used in this study were divided into STZ-treated (STZ, n = 12) and nontreated groups (control, n = 12). Four days prior to surgery, rats in the STZ group were subcutaneously administered 60 mg/kg STZ intraperitoneally, while rats in the control group were administered 1 mL saline/kg. An incision was made in the dorsal dermal tissue of all rats, and either ABS or no haemostatic agent (NHAA) was applied to the wound before suturing. All of the rats were euthanised on postoperative day 4. Blood and skin samples were evaluated biochemically and histologically.

RESULTS

The results showed that STZ treatment impaired soft-tissue healing, assessed by measuring glutathione and lipid peroxidation levels. Moreover, while good histological results were obtained in the control group treated with ABS, there were fewer benefits in the STZ-treated group.

CONCLUSION

ABS's benefits in the control group seemed to lose their effectiveness under STZ medication.

Attenuation of oxidative stress and cardioprotective effects of zinc supplementation in experimental diabetic rats

Oxidative stress plays a major role in the pathogenesis of diabetes mellitus, which further exacerbates damage of cardiac, hepatic and other tissues. We have recently reported that Zn supplementation beneficially modulates hyperglycaemia and hypoinsulinaemia, with attendant reduction of associated metabolic abnormalities in diabetic rats. The present study assessed the potential of Zn supplementation in modulating oxidative stress and cardioprotective effects in diabetic rats. Diabetes was induced in Wistar rats with streptozotocin, and groups of diabetic rats were treated with 5- and 10-fold dietary Zn interventions (0·19 and 0·38 g Zn/kg diet) for 6 weeks. The markers of oxidative stress, antioxidant enzyme activities and concentrations of antioxidant molecules, lipid profile, and expressions of fibrosis and pro-apoptotic factors in the cardiac tissue were particularly assessed. Supplemental Zn showed significant attenuation of diabetes-induced oxidative stress in terms of altered antioxidant enzyme activities and increased the concentrations of antioxidant molecules. Hypercholesterolaemia and hyperlipidaemia were also significantly countered by Zn supplementation. Along with attenuated oxidative stress, Zn supplementation also showed significant cardioprotective effects by altering the mRNA expressions of fibrosis and pro-apoptotic factors (by >50 %). The expression of lipid oxidative marker 4-hydroxy-2-nonenal (4-HNE) protein in cardiac tissue of diabetic animals was rectified (68 %) by Zn supplementation. Elevated cardiac and hepatic markers in circulation and pathological abnormalities in cardiac and hepatic tissue architecture of diabetic animals were ameliorated by dietary Zn intervention. The present study indicates that Zn supplementation can attenuate diabetes-induced oxidative stress in circulation as well as in cardiac and hepatic tissues.

Bis(maltolato)oxovanadium(IV) (BMOV) Attenuates Apoptosis in High Glucose-Treated Cardiac Cells and Diabetic Rat Hearts by Regulating the Unfolded Protein Responses (UPRs)

Endoplasmic reticulum stress (ERS)-induced unfolded protein response (UPR) and the subsequent cell deaths are essential steps in the pathogenesis of diabetic cardiomyopathy (DCM), a main cause of diabetics' morbidity and mortalities. The bis(maltolato)oxovanadium(IV) (BMOV), a potent oral vanadium complex with anti-diabetic properties and insulin-mimicking effects, was shown to improve cardiac dysfunctions in diabetic models. Here, we examined the effects of BMOV on UPR pathway protein expression and apoptotic cell deaths in both high glucose-treated cardiac H9C2 cells and in the hearts of diabetic rats. We show that in both the high glucose-treated cardiac cells and in the hearts of streptozotocin (STZ) diabetic rats, there was an overall activation of the UPR signaling, including both apoptotic (e.g., the cascades of PERK/EIf2α/ATF4/CHOP and of IRE1/caspase 12/caspase 3) and pro-survival (GRP78 and XBP1) signaling. A high amount of apoptotic cell deaths was also detected in both diabetic conditions. The administration of BMOV suppressed both the apoptotic and pro-survival UPR signaling and significantly attenuated apoptotic cell deaths in both conditions. The overall suppression of UPR signaling by BMOV suggests that the drug protects diabetic cardiomyopathy by counteracting reactive oxygen species (ROS) and endoplasmic reticulum (ER) stress. Our findings lend support to promote the use of BMOV in the treatment of diabetic heart diseases.

Improvement in Serum Biochemical Alterations and Oxidative Stress of Liver and Pancreas following Use of Royal Jelly in Streptozotocin-Induced Diabetic Rats

OBJECTIVE

This study aimed to evaluate the effects of royal jelly (RJ) on serum biochemical alterations and oxidative stress status in liver and pancreas of streptozotocin (STZ)- induced diabetic rats.

MATERIALS AND METHODS

In this experimental study, thirty two male Wistar rats were divided into the following four groups (n=8/group): i. Control (C), ii. Diabetic (D), iii. Royal jelly (R), and iv. Royal jelly-treated diabetic (D/R) groups. Diabetes was induced by single intraperitoneal (IP) injection of STZ (60 mg/kg). The RJ [100 mg/kg body weight (BW)] was administered orally for 42 days. Blood samples were used to determine serum levels of insulin, high density lipoprotein cholesterol (HDL-c), total protein (TP), albumin, alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), and fasting blood glucose (FBG). Also, the antioxidant status was evaluated by determining the levels of malondialdehyde (MDA), catalase (CAT) and ferric reducing antioxidant power (FRAP) in liver and pancreas. Data were analyzed by one-way analysis of variance (ANOVA) with P<0.05 as the significant level.

RESULTS

STZ-induced diabetic rats showed a significant elevation in the serum levels of AST, ALT, ALP and FBG, whereas there was a significant decrease in serum levels of insulin, albumin, HDL-c and TP (P<0.05). Treatment of the diabetic rats with RJ restored the changes of the above parameters to their normal levels (P<0.05). In addition, RJ significantly improved reduced levels of FRAP and CAT as well as high MDA level in liver and pancreas (P<0.05).

CONCLUSION

RJ improves oxidative damage induced by STZ in the liver and pancreas of rats; therefore, it can be considered as an effective and alternative treatment for diabetes.

Effects of Melatonin on Oxidative Stress in Streptozotocin-Induced Diabetic Rats

Oxidative stress plays an important role in diabetes and other oxygen-related diseases. Melatonin, a pineal hormone thought to be a scavenger of oxygen radicals and a potentially advantageous therapeutic agent in diseases having oxidative stress, was administered (10 mg/kg ip, in gum tragacanth to prolong its absorption, once a day for 4 successive days) to normal and 30-day streptozotocin-induced diabetic Sprague-Dawley rats, after which markers of oxidative stress were assessed in the liver, kidney, intestine, and spleen. Alanine and aspartate aminotransferase activities in serum, which were increased after diabetes, were not increased further by melatonin administration, indicating that there was no melatonin-related liver toxicity. Most melatonin-induced effects were seen in the liver, and very few in extrahepatic tissues. In livers of diabetic rats, reduced concentration of nitrite and increased lipid peroxidation were both restored to normal levels following treatment with melatonin. Hepatic glutathione peroxidase activity was not changed in diabetics, but was decreased after melatonin administration in both normal and diabetic animals. Total glutathione concentrations were significantly decreased in livers of all diabetics and were not normalized by melatonin treatment. Hepatic superoxide dis-mutase activity was elevated following melatonin dosing in normal rats, but dropped below normal levels in diabetic rats and was not restored by melatonin treatment. Glutathione 5-transferase activity was higher than normal in melatonin-dosed normal rat livers. These results suggest that after 4 days of administration, melatonin may enable various enzymes of the hepatic antioxidative defense system to better detoxify harmful oxygen radicals without producing overt toxicity in a disease such as diabetes.

Effect of Melatonin on Phase I and II Biotransformation Enzymes in Streptozotocin-Induced Diabetic Rats

Melatonin, a pineal secretory product known to be a scavenger of oxygen radicals, is widely used as a dietary supplement, although its toxicity has not been well characterized. Melatonin was administered (10 mg/kg IP in gum tragacanth, once a day for 4 successive days) to normal and 30-day streptozotocin-induced diabetic male Sprague-Dawley rats, after which activities of phase I and phase II biotransformation enzymes were assessed in the liver, kidney, intestine, and spleen. Most melatonin-induced effects were seen in the liver, and a few in extrahepatic tissues. In the liver, the effects of diabetes were reversed in two instances: hydroxylation of benzo[a]pyrene and glutathione S-transferase activity toward 1-chloro-2,4-dinitrobenzene. In contrast to its effect on the phase I enzymes studied, whose activities were inhibited or unaffected by melatonin treatment, this treatment led to increased activity of glucuronyl transferase toward 4-methylumbelliferone in intestine of diabetic rats and toward 4-hydroxybiphenylin liver of normal rats. Hepatic glutathione S-transferaseactivity was also induced in normal rats after melatonin treatment, though the diabetic induction of this enzyme activity was reversed by melatonin. These results suggest that in addition to being a radical scavenger, melatonin, after 4 days of administration, does not induce the phase I enzymes studied, but may induce some hepatic phase II enzymes in normal but not diabetic rats.

Role of Mitochondrial Oxidative Stress in Glucose Tolerance, Insulin Resistance, and Cardiac Diastolic Dysfunction

BACKGROUND

Diabetes mellitus (DM) is associated with mitochondrial oxidative stress. We have shown that myocardial oxidative stress leads to diastolic dysfunction in a hypertensive mouse model. Therefore, we hypothesized that diabetes mellitus could cause diastolic dysfunction through mitochondrial oxidative stress and that a mitochondria-targeted antioxidant (MitoTEMPO) could prevent diastolic dysfunction in a diabetic mouse model.

METHODS AND RESULTS

C57BL/6J mice were fed either 60 kcal % fat diet (high-fat diet [HFD]) or normal chow (control) for 8 weeks with or without concurrent MitoTEMPO administration, followed by in vivo assessment of diastolic function and ex vivo studies. HFD mice developed impaired glucose tolerance compared with the control (serum glucose=495±45 mg/dL versus 236±30 mg/dL at 60 minutes after intraperitoneal glucose injection, P<0.05). Myocardial tagged cardiac magnetic resonance imaging showed significantly reduced diastolic circumferential strain (Ecc) rate in the HFD mice compared with controls (5.0±0.3 1/s versus 7.4±0.5 1/s, P<0.05), indicating diastolic dysfunction in the HFD mice. Systolic function was comparable in both groups (left ventricular ejection fraction=66.4±1.4% versus 66.7±1.2%, P>0.05). MitoTEMPO-treated HFD mice showed significant reduction in mitochondria reactive oxygen species, S-glutathionylation of cardiac myosin binding protein C, and diastolic dysfunction, comparable to the control. The fasting insulin levels of MitoTEMPO-treated HFD mice were also comparable to the controls (P>0.05).

CONCLUSIONS

MitoTEMPO treatment prevented insulin resistance and diastolic dysfunction, suggesting that mitochondrial oxidative stress may be involved in the pathophysiology of both conditions.

A Polysaccharide from Ganoderma atrum Improves Liver Function in Type 2 Diabetic Rats via Antioxidant Action and Short-Chain Fatty Acids Excretion

The present study was to evaluate the beneficial effect of polysaccharide isolated from Ganoderma atrum (PSG-1) on liver function in type 2 diabetic rats. Results showed that PSG-1 decreased the activities of serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT), while increasing hepatic glycogen levels. PSG-1 also exerted strong antioxidant activities, together with upregulated mRNA expression of peroxisome proliferator-activated receptor-γ (PPAR-γ), glucose transporter-4 (GLUT4), phosphoinositide 3-kinase (PI3K), and phosphorylated-Akt (p-Akt) in the liver of diabetic rats. Moreover, the concentrations of short-chain fatty acids (SCFA) were significantly higher in the liver, serum, and faeces of diabetic rats after treating with PSG-1 for 4 weeks. These results suggest that the improvement of PSG-1 on liver function in type 2 diabetic rats may be due to its antioxidant effects, SCFA excretion in the colon from PSG-1, and regulation of hepatic glucose uptake by inducing GLUT4 translocation through PI3K/Akt signaling pathways.

Ameliorative effect of quercetin nanorods on diabetic mice: mechanistic and therapeutic strategies

Quercetin is a natural polyphenolic compound that acts as a strong antioxidant for reactive oxygen species (ROS) generated by any physical or chemical action.

The antioxidative effects of acidic-, alkalic-, and enzymatic-extractable mycelium zinc polysaccharides by Pleurotus djamor on liver and kidney of streptozocin-induced diabetic mice

BACKGROUND

Edible mushrooms, especially the genus of Pleurotus, have been well studied for their nutrition as well as non-toxic medicinal properties. Recently, much attention has been paid to the therapeutic values of mushrooms in genus of Pleurotus with diabetes mellitus (DM), which was a complex metabolic disorder that induced by increased oxidative stress and characterized by hyperglycemia. However, scare attention has been paid to polysaccharides from P. djamor. Meanwhile, zinc is an essential trace element in the human body and it participates in various pathways of metabolism. Therefore, the objective of present study was aimed to evaluate the protective effects of the three extractable mycelium zinc polysaccharides (MZPS), including acidic-MZPS (Ac-MZPS), alkalic-MZPS (Al-MZPS) and enzymatic-MZPS (En-MZPS), on the liver and kidneys in diabetic mice induced by streptozocin (STZ) aiming to better understand the possible hypoglycemic mechanisms and their health benefits.

METHODS

The Ac-, Al-, and En-MZPS were extracted with hydrochloric acid (1 M), sodium hydroxide (1 M) and snailase (4 %) from P. djamor zinc-enriched mycelium, respectively. The diabetic mice were induced by injection of STZ. Besides the histopathological analyses of liver and kidney, the following biochemical analysis were processed to investigate the antioxidative effects, including activities of superoxide dismutase (SOD), GSH peroxide (GSH-Px) and catalase (CAT), and contents of malondialdehyde (MDA) in liver and kidney homogenate; activities of alamine aminotransferase (ALT) and aspertate aminotransferase (AST), and levels of urea nitrogen (BUN), creatinine (CRE), total cholesterol (TC), albumin (ALB), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C) and very low-density lipoprotein cholesterol (VLDL-C) in serum.

RESULTS

Results showed that the activities of SOD, GSH-Px and CAT were significantly increased, the MDA contents remarkably reduced, and the values of ALT, AST, BUN, CRE, TC, LDL-C and HDL-C observably mitigated in the liver, kidneys and serum of diabetic mice by these three polysaccharides treatment. Biochemical and histopathological analyses also showed that MZPS could alleviate liver and kidneys injury.

CONCLUSION

These results demonstrated that Ac-, Al-, and En-MZPS possessed potent antioxidant activities, and could be used as a potentially functional food for the prevention of diabetes and its complications induced by STZ.

Oxidovanadium(IV) complexes with chrysin and silibinin: anticancer activity and mechanisms of action in a human colon adenocarcinoma model

Vanadium compounds were studied during recent years to be considered as a representative of a new class of nonplatinum metal antitumor agents in combination to its low toxicity. On the other hand, flavonoids are a wide family of polyphenolic compounds synthesized by plants that display many interesting biological effects. Since coordination of ligands to metals can improve the pharmacological properties, we report herein, for the first time, a exhaustive study of the mechanisms of action of two oxidovanadium(IV) complexes with the flavonoids: silibinin Na₂[VO(silibinin)₂2]·6H₂O (VOsil) and chrysin [VO(chrysin)₂EtOH]₂(VOchrys) on human colon adenocarcinoma derived cell line HT-29. The complexes inhibited the cell viability of colon adenocarcinoma cells in a dose dependent manner with a greater potency than that the free ligands and free metal, demonstrating the benefit of complexation. The decrease of the ratio of the amount of reduced glutathione to the amount of oxidized glutathione were involved in the deleterious effects of both complexes. Besides, VOchrys caused cell cycle arrest in G2/M phase while VOsil activated caspase 3 and triggering the cells directly to apoptosis. Moreover, VOsil diminished the NF-kB activation via increasing the sensitivity of cells to apoptosis. On the other hand, VOsil inhibited the topoisomerase IB activity concluding that this is important target involved in the anticancer vanadium effects. As a whole, the results presented herein demonstrate that VOsil has a stronger deleterious action than VOchrys on HT-29 cells, whereby suggesting that Vosil is the potentially best candidate for future use in alternative anti-tumor treatments.

Effect of hydroalcoholic leaves extract of Indigofera spicata Forssk. on blood glucose level of normal, glucose loaded and diabetic rodents

BACKGROUND

Diabetes mellitus is found in all parts of the world and is rapidly increasing in its coverage with alarming rate especially in Asia and Africa. Research is increasingly done with the aim of developing a relatively safe and efficacious anti-diabetic plant based products. Parallelly, this investigation was carried out to evaluate the effect of the hydro alcoholic leaves crude extract of Indigofera spicata (ISP) on the blood glucose level(BGL) of normoglycemic, oral glucose loaded and alloxan induced diabetic rodents.

METHODS

The animals were randomly divided into five groups (n = 6) for all the aforementioned three models. In all models, group-I mice provided 2%tween-80, group-II were treated with 5 mg/kg glibenclamide and the remaining three groups (III, IV & V) were treated with 100, 200, and 400 mg/kg dose of the extract respectively. Statistical significance of differences in BGLs within and between groups was analyzed by SPSS version-21 using one way ANOVA followed by Tukey's post hoc multiple comparison.

RESULT

200 mg/kg and 400 mg/kg extract treated groups of normoglycemic mice showed significant (p < 0.05) BGL reduction compared to the pre-exposure level. In case of OGTT model BGL reduction was statistically significant (p < 0.05) in only 400 mg/kg exposed groups at the 120 min of post-exposure compared to the initial level. However, the BGL reducing effect of doses of the extract at the 4(th), 6(th) and 10(th) hours of post treatment on diabetic mice was found statistically significant compared to both the negative control (p < 0.001) and their respective pretreatment levels (p < 0.05).

CONCLUSION

As it is claimed in ethnobotanical studies, the hydroalcoholic crude extract of ISP leaves have shown prominent anti-diabetic effect and can be therefore used as a good insight for new anti-diabetic drug source with a call for further studies.

Ethanol extract of mango (Mangifera indica L.) peel inhibits α-amylase and α-glucosidase activities, and ameliorates diabetes related biochemical parameters in streptozotocin (STZ)-induced diabetic rats

Peel is a major by-product during processing of mango fruit into pulp. Recent report indicates that the whole peel powder ameliorated diabetes. In the present study, ethanolic extract of mango peel was analysed for its bioactive compounds, evaluated for α-amylase and α-glucosidase inhibitory properties, oral glucose tolerance test, antioxidant properties, plasma insulin level and biochemical parameters related to diabetes. In addition to gallic and protocatechuic acids, the extract also had chlorogenic and ferulic acids, which were not reported earlier in mango peel extracts. The peel extract inhibited α-amylase and α-glucosidase activities, with IC50 values of 4.0 and 3.5 μg/ml. Ethanolic extract of peel showed better glucose utilization in oral glucose tolerance test. Treatment of streptozotocin-induced diabetic rats with the extract decreased fasting blood glucose, fructosamine and glycated hemoglobin levels, and increased plasma insulin level. Peel extract treatment decreased malondialdehyde level, but increased the activities of antioxidant enzymes significantly in liver and kidney compared to diabetic rats. These beneficial effects were comparable to metformin, but better than gallic acid treated diabetic rats. The beneficial effects of peel extract may be through different mechanism like increased plasma insulin levels, decreased oxidative stress and inhibition of carbohydrate hydrolyzing enzyme activities by its bioactive compounds. Thus, results suggest that the peel extract can be a potential source of nutraceutical or can be used in functional foods and this is the first report on antidiabetic properties of mango peel extract.

Inhibition of key enzymes linked to type 2 diabetes and sodium nitroprusside-induced lipid peroxidation in rat pancreas by water-extractable phytochemicals from unripe pawpaw fruit (Carica papaya)

BACKGROUND

Various parts of unripe pawpaw (Carica papaya Linn) fruit have been reportedly used for the management or treatment of diabetes mellitus in folklore medicine. Therefore, the present study sought to investigate the inhibitory effects of the aqueous extract of different parts of unripe pawpaw fruit on key enzymes linked to type 2 diabetes (α-amylase and α-glucosidase) and sodium nitroprusside (SNP)-induced lipid peroxidation in rat pancreas in vitro.

METHODS

The aqueous extracts of the unripe pawpaw (C. papaya) fruit parts were prepared (1:20 w/v) and the ability of the extracts to inhibit α-amylase, α-glucosidase and SNP-induced lipid peroxidation in rat pancreas in vitro was investigated.

RESULTS

The results revealed that all the extracts inhibited α-amylase (IC50=0.87-1.11 mg/mL), α-glucosidase (IC50=1.76-2.64 mg/mL) and SNP-induced lipid peroxidation (IC50=1.99-2.42 mg/mL) in a dose-dependent manner. However, combination of the flesh, seed and peel in equal amounts had the highest inhibitory effect on α-amylase and α-glucosidase activities.

CONCLUSIONS

Strong inhibitory activities of the unripe pawpaw fruit against key enzymes linked to type 2 diabetes and SNP-induced lipid peroxidation in rat pancreas could be part of the mechanism by which unripe pawpaw is used in the management/prevention of diabetes mellitus in folk medicine. However, combining the unripe pawpaw fruit parts in equal amounts exhibited synergistic properties on α-amylase and α-glucosidase inhibitory activities.

Astaxanthin and Corni Fructus protect against diabetes-induced oxidative stress, inflammation, and advanced glycation end product in livers of streptozotocin-induced diabetic rats

This study was conducted to compare the protective effects of astaxanthin (ASX) with Corni Fructus (CF) against diabetes-induced pathologies such as oxidative stress-induced inflammation and advanced glycation end product (AGE) formation in the liver of type 1 diabetic rats. ASX (50 mg/kg body weight/day) or CF (200 mg/kg body weight/day) was orally administered every day for 18 days to streptozotocin (STZ)-induced diabetic rats, and their effects were compared with nondiabetic and diabetic control rats. The administration of CF, but not ASX, decreased both the elevated serum and hepatic glucose concentration in diabetic rats. In diabetic rats, increased levels of AGE, reactive oxygen species, and lipid peroxidation were significantly decreased by treatment with both ASX and CF in the liver of diabetic rats. STZ treatment markedly augmented the protein expressions of AGE, and both ASX and CF efficiently attenuated these increases in hepatic protein expressions. In addition, oxidative stress and proinflammatory protein expressions were upregulated in the diabetic rats. On the contrary, these upregulations of protein expressions were decreased by the administration of ASX or CF. These results suggest that the inhibitory effect of ASX on diabetes-induced hepatic dysfunction could be derived from the blocking of AGE formation and further anti-inflammation and that CF exhibited beneficial effects through the attenuation of hyperglycemia, and thus the inhibition of AGE formation and the inflammatory responses. Therefore, ASX as well as CF may help prevent ongoing diabetes-induced hepatic injury.

Antiproliferative and apoptosis-inducing activity of an oxidovanadium(IV) complex with the flavonoid silibinin against osteosarcoma cells

Flavonoids are a large family of polyphenolic compounds synthesized by plants. They display interesting biological effects mainly related to their antioxidant properties. On the other hand, vanadium compounds also exhibit different biological and pharmacological effects in cell culture and in animal models. Since coordination of ligands to metals can improve or change the pharmacological properties, we report herein, for the first time, a detailed study of the mechanisms of action of an oxidovanadium(IV) complex with the flavonoid silibinin, Na2[VO(silibinin)2]·6H2O (VOsil), in a model of the human osteosarcoma derived cell line MG-63. The complex inhibited the viability of osteosarcoma cells in a dose-dependent manner with a greater potency than that of silibinin and oxidovanadium(IV) (p < 0.01), demonstrating the benefit of complexation. Cytotoxicity and genotoxicity studies also showed a concentration effect for VOsil. The increase in the levels of reactive oxygen species and the decrease of the ratio of the amount of reduced glutathione to the amount of oxidized glutathione were involved in the deleterious effects of the complex. Besides, the complex caused cell cycle arrest and activated caspase 3, triggering apoptosis as determined by flow cytometry. As a whole, these results show the main mechanisms of the deleterious effects of VOsil in the osteosarcoma cell line, demonstrating that this complex is a promising compound for cancer treatments.

Vitamin K1 alleviates streptozotocin-induced type 1 diabetes by mitigating free radical stress, as well as inhibiting NF-κB activation and iNOS expression in rat pancreas

OBJECTIVE

The aim of this study was to understand the mechanism of action of vitamin K1 against streptozotocin (STZ)-induced diabetes.

METHODS

Male Wistar rats were administered 35 mg/kg STZ and after 3 d were treated with vitamin K1 (5 mg/kg, twice a week) for 3 months. Blood glucose was monitored twice a month. At the end of the study, animals were sacrificed and pancreas dissected out and analyzed for free radicals, antioxidants, metabolic enzymes related to glucose, membrane ATPases, histopathological evaluation, and expression of nuclear factor (NF)-κB and inducible nitric oxide synthase (iNOS). Glycated hemoglobin, plasma insulin, and islet area were determined at the end of the study.

RESULTS

Treatment of STZ-induced type 1 diabetic rats with vitamin K1 reduced oxidative stress, enhanced antioxidants, and inhibited aldose reductase in pancreas. Vitamin K1 administration rescued endocrine pancreas from STZ-induced cell death, resulting in enhanced insulin secretion and normal blood glucose and glycosylated hemoglobin levels. Histologic analyses also showed the antidiabetic potential of vitamin K1. Measure of pancreatic islet area showed an increase in the islet area upon vitamin K1 treatment when compared with the STZ-administered group, suggesting the possibility of regeneration. To understand the mechanism involved in vitamin K1 mediated changes, we performed immunohistochemical analyses for NF-κB and iNOS enzyme. Vitamin K1 was shown to suppress NF-κB activation and iNOS expression in the islets upon administration of STZ.

CONCLUSION

This work shows, to our knowledge for the first time, the mechanism of action of vitamin K1 against type 1 diabetes and the possible therapeutic use of this vitamin in stimulating islet cell proliferation/regeneration.

Neuromodulatory effects of hesperidin in mitigating oxidative stress in streptozotocin induced diabetes

Oxidative stress has been implicated in pathogenesis of streptozotocin- (STZ-) induced diabetes mellitus and its complication in central nervous system (CNS). Recent studies have provided insights on antioxidants and their emergence as potential therapeutic and nutraceutical. The present study examined the hypothesis that hesperidin (HP) ameliorates oxidative stress and may be a limiting factor in the extent of CNS complication following diabetes. To test this hypothesis rats were divided into four groups: control, diabetic, diabetic-HP treated, and vehicle for HP treatment group. Diabetes mellitus was induced by a single injection of STZ (65 mg/kg body weight). Three days after STZ injection, HP was given (50 mg/kg b.wt. orally) once daily for four weeks. The results of the present investigation suggest that the significant elevated levels of oxidative stress markers were observed in STZ-treated animals, whereas significant depletion in the activity of nonenzymatic antioxidants and enzymatic antioxidants was witnessed in diabetic rat brain. Neurotoxicity biomarker activity was also altered significantly. HP treatment significantly attenuated the altered levels of oxidative stress and neurotoxicity biomarkers. Our results demonstrate that HP exhibits potent antioxidant and neuroprotective effects on the brain tissue against the diabetic oxidative damage in STZ-induced rodent model.

Protective effects of saffron (its active constituent, crocin) on nephropathy in streptozotocin-induced diabetic rats

The reactive oxygen species take role in pathogenesis of many diseases including hypoxia, hypercholesterolemia, atherosclerosis, nephropathy, hypertension, ischemia–reperfusion damage, and heart defects. The aim of this study was to evaluate whether crocin administration could protect kidney injury from oxidative stress in streptozotocin-induced diabetic rats. The rats were randomly divided into 3 groups each containing 10 animals as follows: group 1, control group; group 2, diabetes mellitus (DM) group; and group 3, DM + crocin group. At the end of the study, trunk blood was collected to determine the plasma levels of blood urea nitrogen (BUN) and creatinine (Cr). The kidney tissue was removed, and biochemical and histological changes were examined. Diabetes caused a significant increase in malondialdehyde (MDA) and xanthine oxidase (XO) activities and a decrease in glutathione (GSH) contents (  p < 0.01) when compared with control group in the rat kidneys. Crocin given to DM rats significantly decreased MDA (  p < 0.01) and XO (  p < 0.05) activities and elevated GSH (  p < 0.05) contents when compared with DM group. Plasma levels of BUN and Cr were significantly higher in the DM group when compared with the control group (  p < 0.01). Pretreatment of the DM animals with crocin decreased the high level of serum Cr and BUN. Control group was normal in histological appearance, but congestion, severe inflammation, tubular desquamation, tubular necrosis, and hydropic degeneration in tubular cells were observed in the DM group. Histopathological changes markedly reduced, and appearance of kidney was nearly similar to control group in DM + crocin group. Our results show that crocin could be beneficial in reducing diabetes-induced renal injury.

Study on total antioxidant status in relation to oxidative stress in type 2 diabetes mellitus

BACKGROUND

Diabetes Mellitus is a condition of increased oxidative stress and requiries antioxidants. The sum of endogenous and food derived antioxidants represents the total antioxidant activity of the system. The cooperation among different antioxidants provides greater protection against damage caused by reactive oxygen species or reactive nitrogen species, than any single compound alone. Thus the overall antioxidant capacity may provide more relevant biological information compared to that obtained by the measurement of individual components, as it considers the cumulative effect of all antioxidants present in plasma and body fluids and hence the study.

MATERIALS AND METHODS

The study population included healthy volunteers from staff of Sree Balaji Medical College & Hospital (SBMC&H) and Type 2 Diabetic patients attending SBMC&H, Chennai, India. Malondialdehyde levels and total antioxidant status of the case and controls was assessed.

RESULTS

A significant decrease in the total antioxidant status among Diabetic patients and significant increase in their malondialdehyde levels in comparison to healthy controls was observed.

CONCLUSION

Type 2 Diabetes Mellitus is a condition in which there is increased oxidative stress as evident by increased Malondialdehyde levels and the condition calls for utilization of antioxidants to combat the oxidants thereby resulting in decreased total antioxidants status.

Beneficial Antioxidative and Antiperoxidative Effect of Cinnamaldehyde Protect Streptozotocin-Induced Pancreatic β-Cells Damage in Wistar Rats

The present study was aimed to evaluate the antioxidant defense system of cinnamaldehyde in normal, diabetic rats and its possible protection of pancreatic β-cells against its gradual loss under diabetic conditions. In vitro free radical scavenging effect of cinnamaldehyde was determined using DPPH (1,1-diphenyl-2-dipicrylhydrazyl), superoxide radical, and nitric oxide radical. Streptozotocin (STZ) diabetic rats were orally administered with cinnamaldehyde at concentrations of 5, 10 and 20 mg/kg body weight for 45 days. At the end of the experiment, the levels of plasma lipid peroxides and antioxidants such as vitamin C, vitamin E, ceruloplasmin, catalase, superoxide dismutase, reduced glutathione and glutathione peroxidase were determined. A significant increase in the levels of plasma glucose, vitamin E, ceruloplasmin, and lipid peroxides and significant decrease in the levels of plasma insulin and reduced glutathione were observed in the diabetic rats. Also the activities of pancreatic antioxidant enzymes were altered in the STZ-induced diabetic rats. The altered enzyme activities were reverted to near-normal levels after treatment with cinnamaldehyde and glibenclamide. Histopathological studies also revealed a protective effect of cinnamaldehyde on pancreatic β-cells. Cinnamaldehyde enhances the antioxidant defense against reactive oxygen species produced under hyperglycemic conditions and thus protects pancreatic β-cells against their loss and exhibits antidiabetic properties.