On the Anticataractogenic Effects of L-Carnosine: Is It Best Described as an Antioxidant, Metal-Chelating Agent or Glycation Inhibitor?
Purpose.L-Carnosine is a naturally occurring dipeptide which recently gained popularity as an anticataractogenic agent due to its purported antioxidant activities. There is a paucity of research and conclusive evidence to support such claims. This work offers compelling data that help clarify the mechanism(s) behind the anticataract properties of L-carnosine.Methods.Direct in vitro antioxidant free radical scavenging properties were assayed using three different antioxidant (TEAC, CUPRAC, and DPPH) assays. Indirect in vitro and ex vivo antioxidant assays were studied by measuring glutathione bleaching capacity and total sulfhydryl (SH) capacity of bovine lens homogenates as well as hydrogen-peroxide-stress assay using human lens epithelial cells. Whole porcine lenses were incubated in high galactose media to study the anticataract effects of L-carnosine. MTT cytotoxicity assays were conducted on human lens epithelial cells.Results.The results showed that L-carnosine is a highly potent antiglycating agent but with weak metal chelating and antioxidant properties. There were no significant decreases in lens epithelial cell viability compared to negative controls. Whole porcine lenses incubated in high galactose media and treated with 20 mM L-carnosine showed a dramatic inhibition of advanced glycation end product formation as evidenced by NBT and boronate affinity chromatography assays.Conclusion.L-Carnosine offers prospects for investigating new methods of treatment for diabetic cataract and any diseases that are caused by glycation.
Faculty of Science, Engineering and Computing, Kingston University London, Penrhyn Road, Kingston upon Thames KT1 2EE, UK; Department of Pharmaceutics, Faculty of Pharmacy, Minia University, Minia, Egypt.
Hamdy
0000-0002-0460-9812
H
Abdelkader
Faculty of Science, Engineering and Computing, Kingston University London, Penrhyn Road, Kingston upon Thames KT1 2EE, UK.
Michael
0000-0003-1631-5325
M
Longman
Faculty of Science, Engineering and Computing, Kingston University London, Penrhyn Road, Kingston upon Thames KT1 2EE, UK; School of Pharmacy, The University of Auckland, Auckland, New Zealand.
Raid G
RG
Alany
Faculty of Science, Engineering and Computing, Kingston University London, Penrhyn Road, Kingston upon Thames KT1 2EE, UK.
Barbara
0000-0002-8661-6353
B
Pierscionek
D000975:Antioxidants; D002336:Carnosine / Q000008:administration & dosage / Q000627:therapeutic use*; D002386:Cataract / Q000517:prevention & control*; D002614:Chelating Agents / Q000494:pharmacology; D006801:Humans; D007908:Lens, Crystalline / Q000187:drug effects
D000975:Antioxidants; D002614:Chelating Agents; D002336:Carnosine