Evaluation of Aldose Reductase, Protein Glycation, and Antioxidant Inhibitory Activities of Bioactive Flavonoids in <i>Matricaria recutita</i> L. and Their Structure-Activity Relationship

Abstract

The inhibitory activities of <i>Matricaria recutita</i> L. 70% methanol extract were evaluated by isolating and testing 10 of its compounds on rat lens aldose reductase (RLAR), advanced glycation end products (AGEs), and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging. Among these compounds, apigenin-7-<i>O</i>-<i>β</i>-D-glucoside, luteolin-7-<i>O</i>-<i>β</i>-D-glucoside, apigenin-7-<i>O</i>-<i>β</i>-D-glucuronide, luteolin-7-<i>O</i>-<i>β</i>-D-glucuronide, 3,5-<i>O</i>-di-caffeoylquinic acid, apigenin, and luteolin showed potent inhibition, and their IC₅₀ values in RLAR were 4.25, 1.12, 1.16, 0.85, 0.72, 1.72, and 1.42 <i>μ</i>M, respectively. Furthermore, these compounds suppressed sorbitol accumulation in rat lens under high-glucose conditions, demonstrating their potential to prevent sorbitol accumulation ex vivo. Notably, luteolin-7-<i>O</i>-<i>β</i>-D-glucuronide and luteolin showed antioxidative as well as AGE-inhibitory activities (IC₅₀ values of these compounds in AGEs were 3.39 and 6.01 <i>μ</i>M). These results suggest that the <i>M. recutita</i> extract and its constituents may be promising agents for use in the prevention or treatment of diabetic complications.