Comparative Study on the Status of Glycation Precursors, Advanced Glycation End Products, and Cell Viability Under Effects of Kaempferol, Myricetin, and Azaleatin in HGC-27 Cell Line

Abstract

rosis, and Alzheimer’s Disease (Hartog et al., 2007; Reddy and Obrenovich, 2002). However, in response to increased glycation, some of the accumulated glycation adducts may be omitted by enzymatic repair mechanisms while others are degraded by proteases (Vander and Hunsaker, 2003; Nemet et al., 2006). The major contributing molecules with different potentials to form AGEs are 3-deoxyglucoson, glyoxal, pentosidine, and methylglyoxal. 3-Deoxyglucosone (3-DG) is a highly reactive dicarboxyl sugar and a precursor for AGE generation by cells, particularly when excessive glucose is taken up or when a person is diabetic. In addition, it can damage some antioxidant enzymes such as glutathione reductase, which is inactivated by excess 3-deoxyglucosone (Tauer et al., 2001; Schalwijk et al., 1999). On the other hand, pentosidine is a fluorescent molecule and represents an adequate and sensitive marker for all AGEs within cells. It is an imidazole [4,5b] pyridinum ring formed by cross linking between lysine and arginine residues (Dyer et al., 1991; Spacek and Adam, 2002). The elevation of pentosidine is associated with ageing and related complications, including cartilage stiffness and damage that causes physical disability (Senolt et al., 2005; Verzijl et al., 2002). Glyoxal may be formed via autoxidation and spontaneous degradation of glucose by retro-aldol condensation under physiological conditions (Paul et al., 1999). The methylated form of this compound, methylglyoxal, can be produced by fragmentation of 3-deoxyglucosone and is also a byproduct of glycolysis and amino acid catabolism (Frank et al., 1996). Current knowledge of glycation indicates that it may be an Comparative Study on the Status of Glycation Precursors, Advanced Glycation End Products, and Cell Viability Under Effects of Kaempferol, Myricetin, and Azaleatin in HGC-27 Cell Line