Quercetin, a flavonoid antioxidant, modulates endothelium-derived nitric oxide bioavailability in diabetic rat aortas

Mittal, Ajay; Achike, Francis I.; Mohd, Mustafa Ali; Mustafa, Mohd Rais

doi:10.1016/j.niox.2007.04.001

Cited by 88 publications

(56 citation statements)

References 16 publications

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“…Our results confirm that flavonoids, such as quercetin and (Ҁ)-epicatechin, do indeed influence NO status in humans as reported in recent in vitro experiments (36) and animal studies (37). Quercetin may have increased NO production by increasing endothelial NOS (eNOS) activity (37,38) or by enhancing the bioavailability of endothelium-derived NO (39). (Ҁ)-Epicatechin has been shown to elevate NO in endothelial cells in vitro via the inhibition of NADPH oxidase (36).…”

Section: Discussionsupporting

confidence: 85%

“…The mean (Ȁ SEM) baseline circulating concentrations of total quercetin and total (Ҁ)-epicatechin were 0.84 Ȁ 0. 39 (pg/ mmol creatinine) (B) 1 All values are x Ȁ SEM; n ҃ 12. There were no significant differences at baseline and no significant difference in plasma or urinary F 2 -isoprostanes between the treatment groups and the water group.…”

Section: Quercetin (؊)-Epicatechin and Egcg Absorptionmentioning

confidence: 99%

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Pure dietary flavonoids quercetin and (−)-epicatechin augment nitric oxide products and reduce endothelin-1 acutely in healthy men

Loke

Hodgson

Proudfoot

et al. 2008

The American Journal of Clinical Nutrition

339

254

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Background: Dietary flavonoids may improve endothelial function and ultimately lead to beneficial cardiovascular effects. Objective: The objective was to assess whether pure dietary flavonoids can modulate nitric oxide and endothelin-1 production and thereby improve endothelial function. Design: A randomized, placebo-controlled, crossover trial in 12 healthy men was conducted to compare the acute effects of the oral administration of 200 mg quercetin, (Ҁ)-epicatechin, or epigallocatechin gallate on nitric oxide, endothelin-1, and oxidative stress after nitric oxide production was assessed via the measurement of plasma S-nitrosothiols and plasma and urinary nitrite and nitrate concentrations. The effects on oxidative stress were assessed by measuring plasma and urinary F 2 -isoprostanes. Plasma and urinary concentrations of quercetin, (Ҁ)-epicatechin, and epigallocatechin gallate were measured to establish the absorption of these flavonoids. Results: Relative to water (control), quercetin and (Ҁ)-epicatechin resulted in a significant increase in plasma S-nitrosothiols, plasma nitrite, and urinary nitrate concentrations (P 0.05), but not in plasma nitrate or urinary nitrite. Epigallocatechin gallate did not alter any of the measures of nitric oxide production. Quercetin and (Ҁ)-epicatechin resulted in a significant reduction in plasma endothelin-1 concentration (P 0.05), but only quercetin significantly decreased the urinary endothelin-1 concentration. None of the 3 treatments significantly changed plasma or urinary F 2 -isoprostane concentrations. Significant increases in the circulating concentrations of the 3 flavonoids were observed (P 0.05) after the corresponding treatment. Conclusions: Dietary flavonoids, such as quercetin and (Ҁ)-epicatechin, can augment nitric oxide status and reduce endothelin-1 concentrations and may thereby improve endothelial function.

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Section: Discussionsupporting

confidence: 85%

Section: Quercetin (؊)-Epicatechin and Egcg Absorptionmentioning

confidence: 99%

Pure dietary flavonoids quercetin and (−)-epicatechin augment nitric oxide products and reduce endothelin-1 acutely in healthy men

Loke

Hodgson

Proudfoot

et al. 2008

The American Journal of Clinical Nutrition

339

254

View full text Add to dashboard Cite

show abstract

“…Studies by Lansky and Newman (2006) and Wang et al (2010) have documented the presence of gallic acid and quercetin in P. granatum leaves which supports our finding. Further, the protective effects of quercetin in various renal disorders have also been reported (Kanter et al, 2012;Machha et al, 2007). Thus it is clear that the renal protective potential of PGFF in the present study is due to its major flavonoid component quercetin.…”

Section: Body Weight (G)supporting

confidence: 73%

Flavonoid rich fraction ofPunica granatumimproves early diabetic nephropathy by ameliorating proteinuria and disturbed glucose homeostasis in experimental animals

Ankita

Deepti

Nilam

2014

Pharmaceutical Biology

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Context: Different parts of Punica granatum Linn. (Punicaceae) are traditionally used as renal protective agents in the Indian system of medicine. However, there is paucity of information regarding its role in diabetic nephropathy. Objective: The present study investigates the nephroprotective potential of flavonoid-rich fraction of P. granatum leaves in streptozotocin (STZ)-induced early diabetic nephropathy in experimental animals. Materials and methods: Experimental diabetic nephropathy was induced in Wistar rats by single intraperitonial injection of STZ (65 mg/kg) dissolved in ice cold citrophosphate buffer (pH 4.3). After induction rats were divided into five groups (6 normal; 24 diabetic) and administered with glibenclamide (5 mg/kg) and three dose levels of flavonoid-rich fraction of P. granatum leaves (PGFF), i.e. 50, 100, and 200 mg/kg body weight/day for 28 d. Fasting blood glucose, lipid profile, serum albumin, serum total protein, serum creatinine, blood urea nitrogen (BUN) glycosylated hemoglobin, and biomarkers of kidney oxidative stress were assessed at the end of the treatment period. Urine was analyzed for the measurement of total protein, albumin, and creatinine clearance. Kidney sections were subjected to histopathological study. Results: Daily oral administration of variable dose levels of PGFF for 28 d normalized various biochemical, metabolic, and histopathological changes in the diabetic rats. PGFF significantly (p50.01 and p50.05) improved the glycemic status and renal function in diabetic rats as compared with diabetic control rats. Discussion and conclusion: The results of our study thus prove the protective effect of PGFF in early diabetic nephropathy by ameliorating proteinuria and disturbed glucose homeostasis in experimental animals.

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“…Recently, we have reported that reduced NO levels in GI tissues is the pivotal reason for diabetes-induced GI dysfunction [19] . Quercetin is reported to enhance the bioavailability of NO in diabetic rat aortas [25] . Thus, quercetin might have produced beneficial effects in diabetic rats through modulation of NO levels in the GIT.…”

Section: Discussionmentioning

confidence: 99%

Influence of Quercetin on Diabetes-Induced Alteration in CYP3A Activity and Bioavailability of Pioglitazone in Rats

Umathe¹

2009

American Journal of Infectious Diseases

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Problem statement: Quercetin-a common bioflavonoid, is present in herbal preparations consumed by diabetic patients along with routine anti-diabetic agents. We recently showed that quercetin increases the bioavailability of pioglitazone in non-diabetic rats. Thus, present study investigated whether this pharmacokinetic interaction is also evident in diabetic animals, especially because diabetic subjects have altered Gastrointestinal (GI) function and CYP3A activity. Approach: The study was carried out in alloxan-induced (40 mg kg −1 , i.v.) diabetic rats. After 2 weeks of diabetes induction, rats were treated for 2 weeks with quercetin (10 mg kg, p.o.) or vehicle (5% methyl cellulose, 10 mL kg). At the end of 4 weeks, these rats were used to investigate: (1) GI function in terms of gastric emptying and intestinal transit of semisolid barium sulphate meal; (2) CYP3A activity in liver and intestinal microsomes by erythromycin N-demethylase assay; (3) plasma levels of orally and intravenously administered pioglitazone (10 mg kg v.). Results:The results revealed that diabetic rats exhibited: (1) delayed gastric emptying and intestinal transit; (2) decreased CYP3A activity and (3) a significant increase in the oral and intravenous AUC 0-∞ of pioglitazone as compared to non-diabetic rats. Quercetin treatment prevented the diabetes-induced GI dysfunction, whereas diabetes-induced decrease in CYP3A activity and increased bioavailability of pioglitazone remained unaffected. Conclusion: The results suggested that quercetin attenuated GI dysfunction but did not affect the bioavailability of pioglitazone in diabetic rats contrary to the increase reported in nondiabetic rats. However, the safety of co-joint use of quercetin containing herbs and pioglitazone in clinical practice requires further pharmacokinetic substantiation.

show abstract

Quercetin, a flavonoid antioxidant, modulates endothelium-derived nitric oxide bioavailability in diabetic rat aortas

Cited by 88 publications

References 16 publications

Pure dietary flavonoids quercetin and (−)-epicatechin augment nitric oxide products and reduce endothelin-1 acutely in healthy men

Pure dietary flavonoids quercetin and (−)-epicatechin augment nitric oxide products and reduce endothelin-1 acutely in healthy men

Flavonoid rich fraction ofPunica granatumimproves early diabetic nephropathy by ameliorating proteinuria and disturbed glucose homeostasis in experimental animals

Influence of Quercetin on Diabetes-Induced Alteration in CYP3A Activity and Bioavailability of Pioglitazone in Rats

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