Effect of standardized Eucalyptus globulus leaf extract on brain oxidative stress and aberrant neurochemistry of fructose-streptozotocin-induced diabetic rats.

The neuro-pharmacological effect of Eucalyptus globulus ethanol leaf extract in fructose-streptozotocin-induced diabetic rats was evaluated in this study. The phytochemical analysis of the extract was carried out using HPLC-DAD. Diabetes was induced in rats with 10% fructose in drinking water and a single intraperitoneal injection of 40 mg/kg streptozotocin (STZ). Diabetic animals were orally treated with 100-400 mg/kg of the extract for 21 days with glibenclamide as the reference drug. Blood and brain tissue were processed for the determination of serum electrolyte levels, hematological indices, and biochemical estimations. Ergosterol, pinitol, catechin, quercetin, robinetinidol, and other polyphenols were identified in the extract. Diabetic animals showed decreased serum potassium and sodium ion levels and decreased hematocrit, hemoglobin, red blood cells, white blood cells and lymphocytes but increased neutrophils. The brains of animals in the untreated diabetic group with increased blood glucose level showed oxidative stress (increased level of MDA and myeloperoxidase but decreased level of reduced glutathione and superoxide dismutase) and disturbed neurochemistry (increased level of acetylcholinesterase and monoamine oxidase but decreased level of Na+K+ATPase, tyrosine hydroxylase and dopamine). Administration of the Eucalyptus globulus leaf extract remarkably ameliorated the observed hyperglycemia, electrolyte, and hematological imbalances in animals. In addition, the administration of the extract attenuated the brain redox imbalance, and neurochemical disturbances in the rats. These results show that Eucalyptus globulus leaves contain antioxidant and neurotransmitter modulating phytochemicals with the potential to be developed as therapeutic agents for the management of diabetic cerebrovascular problems and related complications.

Comparative influence of kolaviron and coenzyme Q10 on complex I activity, glutamate clearance, 3,4-dihydroxyphenethylamine metabolism, and redox stress in rotenone-induced neurotoxicity.

3,4-dihydroxyphenethylamine (dopamine) depletion, inhibition of complex I activity, oxidative stress, and glutamate excitotoxicity are cardinal biochemical features of neurotoxicity induced by systemic unilateral infusion of rotenone. Kolaviron (KV), a biflavonoid from Garcinia kola seeds, has been proven to have pharmacological effects against neurotoxicity. Coenzyme Q10 plays an essential role in mitochondrial oxidative phosphorylation and as an antioxidant. This study examined the comparative influence of kolaviron and coenzyme Q10 on complex I activity, dopamine metabolism, glutamate clearance, and redox stress in rotenone-induced neurotoxicity in the cortex, hippocampus, and striatum of the brain of rats. Adult Male Wistar rats were pretreated with 200 mg/kg KV or 100 mg/kg coenzyme Q10 for 7 days followed by administration of a progressive six doses of 1.5 mg/kg rotenone within the next 48 h after which the animals were euthanized and the brain excised. On the cortical, hippocampal, and striatal regions of the brain, complex I activity, dopamine metabolism, oxidative stress markers, as well as glutamate metabolism were carried out and analyzed. In all brain regions examined, KV and coenzyme Q10 pretreatment modulated complex I activity, ameliorated redox imbalance, and enhanced dopamine metabolism via increasing the activity of tyrosine hydroxylase and decreasing monoamine oxidase activity. KV facilitated glutamate clearance through augmentation of glutamate dehydrogenase and glutamine synthetase activities.  The activity of KV was comparable to that of the mitochondrial membrane antioxidant compound, coenzyme Q10, this indicates that KV is a promising therapeutic agent in the treatment of Parkinson's disease and its activity compares well with coenzyme Q10.

Effects of Catechin, Quercetin and Taxifolin on Redox Parameters and Metabolites Linked with Renal Health in Rotenone-toxified Rats.

Nephrotoxicity, with the attendant risk of progression to kidney failure, is a growing problem in many parts of the world. Current orthodox treatment options for nephrotoxicity and kidney failure are limited and there is need for alternative or complementary approaches. This study aimed at evaluating the effect of three structurally related flavonoids, catechin, quercetin and taxifolin on renal redox and metabolite biochemical disturbances in rotenone intoxicated animals. Male Wistar rats were administered 1.5 mg/kg rotenone (s.c.) for ten days followed by post-treatment with catechin (5, 10 or 20 mg/kg), quercetin (5, 10, or 20 mg/kg) and taxifolin (0.25, 0.5 or 1.0 mg/kg) (s.c.), for 3 days. Renal redox indices and levels of renal-related metabolites (creatinine, urea and uric acid) were assessed after sacrifice of animals. Catechin, quercetin and taxifolin significantly attenuated rotenone-induced effects on oxidative stress markers and metabolites linked to renal health.  Quercetin was clearly more effective than catechin. The activity demonstrated by taxifolin, despite being administered at the lowest doses, was compelling. The results highlight the potential of these phytochemicals in the management of renal dysfunction. The findings additionally suggest a correlation between the structure of the flavonoids and their activity but also indicate that additional structural considerations beyond conventionally acknowledged ones may be involved.

Antidiabetic potential of methanolic and flavonoid-rich leaf extracts of Synsepalum dulcificum in type 2 diabetic rats.

BACKGROUND: Synsepalum dulcificum is a plant indigenous to West Africa. The fruit is used to modify taste of foods to sweetness. OBJECTIVES: This study aims to investigate the antidiabetic potentials of both methanolic and flavonoid-rich leaf extracts of S. dulcificum (MSD and FSD respectively) in type 2 diabetic Wistar albino rats. MATERIALS AND METHODS: Sixty three rats were randomly distributed into nine groups of seven animals each with group 1 serving as the normal control. Groups 2 to 7 were given 10% fructose in their drinking water for 14 days, after which 40 mg/kg of streptozotocin was administered. Group 2 animals served as the diabetic control, while groups 3, 4, 5, 6 and 7 were treated with 30 mg/kg MSD, 60 mg/kg MSD, 30 mg/kg FSD, 60 mg/kg FSD and 5 mg/kg glibenclamide respectively. Groups 8 and 9, contained healthy animals, and were treated with only 60 MSD, and 60 mg/kg FSD respectively. Biochemical parameters such as liver and kidney function tests, lipid profile, as well as lipid peroxidation and antioxidant enzymes were assessed in addition to histopathology. RESULTS: It was observed that daily oral administration of MSD and FSD for 21 days significantly (p < 0.05) improved the observed pathological changes as a result of type 2 diabetes. CONCLUSION: It could be deduced from results obtained in this study that methanolic and flavonoid-rich leaf extracts of S.dulcificum have antidiabetic potential in type 2 diabetic rats.

Rutin and quercetin show greater efficacy than nifedipin in ameliorating hemodynamic, redox, and metabolite imbalances in sodium chloride-induced hypertensive rats.

Rutin and quercetin were investigated for their effects on blood pressure and antioxidant defense system of rats fed with 8% sodium chloride-supplemented diet (high salt diet) for 6 weeks. Animals fed with high salt diet demonstrated an increase in systolic, diastolic, pulse, and mean arterial blood pressures (p < 0.05) as well as lipid peroxidation but decreases in the activities of antioxidant enzymes compared with control group. Groups post-treated with rutin and quercetin for 2 weeks showed significant reversals in the values of these indices compared with the group fed with only the high salt diet but not post-treated. The high salt diet also led to significant increase in serum glucose, urea, creatinine, triglycerides, low-density-lipoprotein, and total cholesterol concentrations. Treatment with rutin and quercetin ameliorated the effects of high salt diet on these biochemical indices. The reference standard, nifedipin was less effective than rutin and quercetin. The results of this study highlight the risk of high salt consumption on cardiovascular health and the potent antioxidant and antihypertensive property of rutin and quercetin.