Linagliptin (LNG), 8-[(3R)-3-aminopiperidin-1-yl]-7-(but-2-yn-1-yl)-3-methyl-1-[(4methylquinazolin-2-yl)methyl]-3,7-dihydro-1H-purine-2,6-dione], is a selective, competitive dipeptidyl peptidase-4 (DPP-4) inhibitor, that was approved in 2011 by USA, Japan and Europe for the treatment of type 2 diabetes (Figure 1A) [1]. Here, DPP4 is linked to type 2 diabetes mellitus.