Effect of cinnamon and its procyanidin-B2 enriched fraction on diabetic nephropathy in rats

Chem Biol Interact. 2014 Oct 5;222:68-76. doi: 10.1016/j.cbi.2014.08.013. Epub 2014 Sep 6.

Abstract

Non-enzymatic protein glycation and resultant accumulation of advanced glycation endproducts (AGE) are implicated in the pathogenesis of diabetic complications including diabetic nephropathy (DN). It is considered that antiglycating agents offer protection against AGE mediated pathologies including DN. Earlier we characterized procyanidin-B2 (PCB2) as the active component from cinnamon (Cinnamomum zeylanicum) that inhibits AGE formation in vitro. In this study, we have investigated the potential of PCB2-enriched fraction of cinnamon to prevent in vivo accumulation of AGE and to ameliorate renal changes in diabetic rats. Streptozotocin-induced diabetic rats were fed with either 3% cinnamon or 0.002% PCB2-fraction in diet for 12weeks. Biochemical analysis of blood and urine was performed at the end of experiment. Evaluation of glomerular markers that serve as indicators of renal function was done by immunohistochemistry, immunoblotting and qRT-PCR. Supplementation of diabetic rats with cinnamon and PCB2-fraction prevented glycation mediated RBC-IgG cross-links and HbA1c accumulation in diabetes rats. Cinnamon and PCB2-fraction also inhibited the accumulation of N-carboxy methyl lysine (CML), a prominent AGE in diabetic kidney. Interestingly, cinnamon and its PCB2-fraction prevented the AGE mediated loss of expression of glomerular podocyte proteins; nephrin and podocin. Inhibition of AGE by cinnamon and PCB2-fraction ameliorated the diabetes mediated renal malfunction in rats as evidenced by reduced urinary albumin and creatinine. In conclusion, PCB2 from cinnamon inhibited AGE accumulation in diabetic rat kidney and ameliorated AGE mediated pathogenesis of DN.

Keywords: AGE; CML; Cinnamon; Diabetic nephropathy; Procyanidin-B2; Rat.

MeSH terms

  • Animals
  • Biflavonoids / administration & dosage*
  • Catechin / administration & dosage*
  • Cell Adhesion Molecules / metabolism
  • Cinnamomum zeylanicum / chemistry*
  • Diabetic Nephropathies / diet therapy*
  • Diabetic Nephropathies / physiopathology
  • Glycated Hemoglobin A / metabolism
  • Glycation End Products, Advanced / metabolism
  • Glycosylation / drug effects
  • Inflammation Mediators / metabolism
  • Intracellular Signaling Peptides and Proteins / genetics
  • Intracellular Signaling Peptides and Proteins / metabolism
  • Kidney / drug effects
  • Kidney / physiopathology
  • Male
  • Membrane Proteins / genetics
  • Membrane Proteins / metabolism
  • Proanthocyanidins / administration & dosage*
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • Rats
  • Rats, Wistar

Substances

  • Biflavonoids
  • Cell Adhesion Molecules
  • Glycated Hemoglobin A
  • Glycation End Products, Advanced
  • Inflammation Mediators
  • Intracellular Signaling Peptides and Proteins
  • Membrane Proteins
  • NPHS2 protein
  • Proanthocyanidins
  • RNA, Messenger
  • nephrin
  • procyanidin B2
  • Catechin