Inhibition Effect of Diosmin Flavanoid on Some Metabolic Enzymes and Investigation of Antioxidant Properties

Diosmin is a natural flavonoid obtained by dehydrating flavanone glycoside hesperidin. This study evaluated the inhibition effects of diosmin flavonoid on human carbonic anhydrases (hCA I and hCA II) and acetylcholinesterase (AChE) enzymes, which are linked to various health issues, and compared the results with standard drugs. The antioxidant potential was assessed using five assays, namely DPPH, ABTS, FRAP, CUPRAC and Fe3+ reducing assays. The results determined that diosmin didn’t exhibit strong antioxidant activity. Additionally, the inhibition effects of diosmin on hCA I, hCA II, and AChE enzymes were examined. It effectively inhibited hCA I and hCA II enzymes with Ki values of 3.84±0.63 nM and 15.64±1.90 nM, respectively (Table 1). For comparison, the Ki values of the standard drug AZA were 1.44 ± 0.32 nM for hCA I and 3.66 ± 0.25 nM for hCA II. On the other hand, diosmin effectively inhibited AChE enzymes with Ki values of 9.31±2.40 nM. The Ki values of the standard drug Tacrine was 6.22±1.95 nM for AChE. These findings suggest that diosmin may serve as a selective enzyme inhibitor, particularly for hCA I, but has limited antioxidant capacity. Diosmin exhibited relatively weak antioxidant activity compared to standard antioxidants.