ABSTRACT
Plant extracts and phytochemicals evidenced the capacity to prevent some diseases associated with oxidative stress and advanced glycation end product (AGE) formation. One of the major polyphenolic constituents in green tea is Epigallocatechin-3-gallate (EGCG), which demonstrated to be responsible for decreased AGE-stimulated gene expression and production of tumor necrosis factor-α and matrix metalloproteinase-13 in human chondrocytes. EGCG has been shown to prevent intracellular AGE formation, trapping reactive dicarbonyl species, such as methylglyoxal and glyoxal, and enhancing the production of proinflammatory cytokines in monocytes under hyperglycemic conditions. EGCG was able to bind lipoproteins and to enhance the antioxidant and antiglycation properties of low-density lipoprotein. Polyphenols present in dietary and medicinal plant species are the most abundant antioxidants. Polyphenols constitute the major group of plant-derived compounds with anti-AGE activities, mainly due to the ability to decrease AGE formation. Flavones and their 3-hydroxy derivatives, flavonols, including their glycosides, methoxides, and other acylated products, make the largest subgroup among all polyphenols.
