148 Original article doi: 10.12980/jclm.4.2016j5-219 ©2016 by the Journal of Coastal Life Medicine. All rights reserved. Sri Lankan black tea (Camellia sinensis L.) inhibits the methylglyoxal mediated protein glycation and potentiates its reversing activity in vitro Walimuni Kanchana Subhashini Mendis Abeysekera 1 , Chatura Tissa Dayendra Ratnasooriya 2 , Wanigasekara Daya Ratnasooriya 3 , Sirimal Premakumara Galbada Arachchige 1* 1 Industrial Technology Institute (ITI), 363, Bauddhaloka Mawatha, Colombo 07, Sri Lanka 2 Faculty of Medicine, University of Colombo, Colombo 08, Sri Lanka 3 Department of Basic Sciences, Faculty of Allied Health Sciences, General Sir John Kotalawala Defense University, Ratmalana, Sri Lanka Journal of Coastal Life Medicine 2016; 4(2): 148-153 Journal of Coastal Life Medicine *Corresponding author: Sirimal Premakumara Galbada Arachchige, Industrial Technology Institute, 363, Bauddhaloka Mawatha, Colombo 07, Sri Lanka. Tel: +94-11-2379800 E-mail: gasp@iti.lk; dg@iti.lk The journal implements double-blind peer review practiced by specially invited international editorial board members. 1. Introduction Glycation, non-enzymatic glycosylation of proteins by glucose is a relatively slow and complex series of endogenous reactions occurring in the body, giving rise to various different glycotoxins which are known as advanced glycation end products (AGEs) [1-5]. Accumulation of AGEs is now implicated as a major factor in the pathogenesis of long term complications of diabetes such as retinopathy, nephropathy and end stage renal disease[1-5]. AGEs are also linked to mechanisms responsible for development and progression of non-diabetic nephropathy, macro-vascular disease, cancer, rheumatic arthritis, osteoarthritis, atherosclerosis, cataract, neurodegenerative diseases including Alzheimer’s disease, Parkinson disease and amyotrophic lateral sclerosis and age-related cognitive decline[2,4]. Further, the formation of AGEs is known to progressively increase with normal ageing, even in the absence of disease[4]. Low molecular weight carbonyl compounds such as glyoxal and methylglyoxal (MGO), most importantly MGO behave as precursors of AGEs[4-6]. They form adducts on proteins, inducing cellular dysfunctions leading to long term diabetes complications and other age related diseases[2,4-6]. Thus, pharmaceutical agents (natural and/ ARTICLE INFO ABSTRACT Objective: To evaluate inhibitory activity of methylglyoxal (MGO) mediated protein glycation and ability to potentiate its reversing activity and range of antioxidant properties of Sri Lankan low grown orthodox orange pekoe grade black tea. Methods: Freeze dried black tea brew (BTB) was used as the sample in this study. Anti- glycation and glycation reversing activity was studied in bovine serum albumin (BSA)-MGO model. Antioxidant properties were studied using total polyphenolic content, total flavonoid content, 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid, 1,1-diphenyl-2-picrylhydrazine and ferric reducing antioxidant power in vitro antioxidant assays. Results: The results demonstrated significant (P < 0.05) and dose dependant inhibition of BSA-MGO glycation [IC 50 : (164.30 ± 4.85) µg/mL], potentiating of its reversing activity [EC 50 : (235.39 ± 5.37) µg/mL] and marked antioxidant properties [total polyphenolic content: (119.55 ± 9.97) mg gallic acid equivalents/g BTB; total flavonoid content: (6.04 ± 1.26) mg quercetin equivalents/g BTB; 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid, 1,1-diphenyl-2- picrylhydrazine and ferric reducing antioxidant power: (3.29 ± 0.06), (1.95 ± 0.15) and (1.31 ± 0.19) mmol Trolox equivalents/g BTB, respectively]. No correlations were observed between antioxidant activity and BSA-MGO glycation. Conclusions: The novel properties observed for Sri Lankan orange pekoe grade black tea indicate its usefulness as a supplementary beverage in managing MGO and advanced glycation end products related diseases and ailments. Article history: Received 5 Nov 2015 Received in revised form 4 Dec 2015 Accepted 22 Dec 2015 Available online 18 Jan 2016 Keywords: Methylglyoxal Advanced glycation end products Glycation reversing Diabetes complications Orange pekoe grade black tea Sri Lankan tea journal homepage: www.jclmm.com