The present study was designed to evaluate the synergistic effects of Quercetin (QE) and quinic acid (QA), which are abundant in the diet to investigate their anti-diabetic and anti-inflammatory role in the kidney and liver of rats.
Methods: Male Sprague Dawley (SD) rats were divided into six groups and combined treatment of (QE+QA) (25, 50 and 100 mg/kg, bw) were administered orally to LPS (10 mg/kg, i.p.) induced rats. The ELISA kit determined the pro-inflammatory cytokines and the commercial kit examined the malondialdehyde (MDA), reduced glutathione (GSH) and catalase (CAT). The expression of Proliferating Cell Nuclear Antigen (PCNA) and Cyclooxygenase 2 (COX-2) were evaluated in kidney while the expression of Bcl-2 and inducible nitric oxide synthase (iNOS) were estimated in liver by immunohistochemistry and western blot.
Results: Combined treatment of (QE+QA) showed anti-inflammatory activity by significantly inhibiting tumor necrosis factor (TNF-α), interlukines (IL-6 & IL-1β) and nitric oxide (NO) production in the liver and kidney tissues of LPS-challenged rat. (QE+QA) supplementation markedly enhanced the body’s cellular antioxidant defense system by significantly restoring the levels of (GSH) and catalase (CAT) in homogenate tissue of liver and kidney. Histopathological examination demonstrated that (QE+QA) could improve pathological abnormalities and reduce the immigration of inflammatory cells in liver and kidney tissues on LPS induced rats. In immunohistochemistry and western blot analysis, the renal PCNA degradation was completely restored while COX-2 was inhibited whereas the hepatic Bcl-2 expression was enhanced and iNOS expression was markedly reduced with combined treatment (QE+QA).
Conclusion: The results indicate that (QE+QA) with 50 and 100 mg/kg significantly attenuates LPS-induced hepatic and renal inflammation in rat, suggesting potential role of the compounds in the combination form might be helpful in the management of diabetes and its related complications.
Keywords: Diabetes; Inflammation; Quercetin; Quinic Acid