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.

Toxicological investigation of aqueous-methanolic extract of the calyces of Hibiscus sabdariffa L.

The aqueous fraction of an aqueous-alcoholic extract of Hibiscus sabdariffa L. calyces was given to Wistar albino rats (150-200g) orally as drugs to study the toxicity of the extract. The rats, which were fed with commercial diet and water ad libitum, were divided into six groups of four rats each. Treatments 1 through 6 received 0, 1, 3, 5, 10 and 15 doses of 250 mg/kg each, respectively; the control group received physiological saline (0.9% NaCl). Results of the studies showed that the levels of serum aspartate aminotransferase (AST) and alanine amino transferase (ALT) were significantly (P<0.05) increased in all the treatments compared with the control group. However, the serum levels of alkaline phosphatase, and lactate dehydrogenase were not significantly (P>0.05) affected. Only the group with 15 doses had their serum level of albumin significantly (P<0.05) increased. However, the results of histopathological studies showed that both the livers and hearts gave no pathological features for all the treatments. The results showed that prolong usage of this extract at 15-dose level could cause liver injury while the effect was mild at small dose levels (1-10). Though the average consumption of 150-180 mg/kg per day appears safe, the extract should be taken with caution bearing in mind that higher doses could affect the liver.