In Vitro Antiradical and Antioxidant Activity of Flavonoid Glycosides and Their Aglycones: Diosmin and Hesperidin Case Study

In recent years, several works have been carried out on the beneficial effect of flavonoids which act as natural antioxidants and help to neutralize free radicals. We analysed the antioxidant activity of two flavonoids, diosmin, and hesperidin, known for their anti-haemorrhoidal effect, before and after acid hydrolysis, for comparison with their corresponding aglycones, namely diosmetin and hesperetin. Ascorbic acid was used as a positive control. For antioxidant activity evaluations, three methods including 2,2’-diphenyl-1-picrylhydrazyl radical (DPPH•) scavenging assay, phosphomolybdate method, and Ferric Reducing Antioxidant Power method (FRAP) were used. The results were expressed as a percentage of inhibition of DPPH• radical and half-maximal inhibitory concentration values (IC50), for the first assay. And for the others, as mg of ascorbic acid equivalents per 100 g of powder: the quantity of ascorbic acid required to produce the same antioxidant activity as 100 g of sample (noted ''Ascorbic Acid Equivalent Antioxidant Capacity'': AEAC mg/100g). Aglycones exhibited significant in vitro antioxidant activity compared to glycosides (p<0.05 DPPH assay; p<0.001 Phosphomolybdate and FRAP assays), with antioxidant effect dose-dependent at the concentration levels used.