From Ethnopharmacology to Active Compound: Effects of Traditional Plant Extracts on Varicose Vein-Related Enzymes and Isolation of Active Flavonoids from Helichrysum plicatum DC. subsp. plicatum

<b>Background:</b> Varicose veins and chronic venous insufficiency are chronic venous disorders involving abnormalities in the venous system. Inflammation, an increase in proteolytic enzymes, and free radicals are important factors that play a role in the varicose vein pathology. <b>Methods:</b> In this study, the antioxidant properties and inhibitor activities of 17 plant extracts used to treat varicose veins in traditional medicine were evaluated against varicose veins-related enzymes (hyaluronidase, elastase, collagenase, lipooxygenase, prolylendopeptidase, and xanthine oxidase). The most effective compounds responsible for the activity of the <i>Helichrysum plicatum</i> subsp. <i>plicatum</i> extract were isolated by open column chromatography techniques. The active compounds were determined to be naringenin, apigenin, and luteolin by spectroscopic methods. In the activity-guided isolation study, the xanthine oxidase enzyme inhibition method was used. <b>Results:</b> The fractions containing naringenin and apigenin (IC₅₀ = 0.269 ± 0.009 µg/mL) and apigenin and luteolin (IC₅₀ = 0.285 ± 0.019 µg/mL) compounds showed synergistic and strong effects against xanthine oxidase and were found to be as active as the positive control allopurinol (IC₅₀ = 0.250 ± 0.006 µg/mL). In the LC-MS/MS analysis of the <i>Helichrysum plicatum</i> extract, quinic acid (22.649 mg compound/g extract), chlorogenic acid (14.573 mg/g extract), isoquercitrin (14.371 mg/g extract), cosmosin (9.885 mg/g extract), and astragalin (11.506 mg/g extract) were detected as the major components. Naringenin, apigenin, and luteolin were detected at concentrations of 1.457, 2.518, and 1.368 mg/g in the extract, respectively. <b>Conclusions:</b> In conclusion, it is predicted that the combination of naringenin, apigenin, and luteolin has a promising use as a conservative treatment option for diseases associated with varicose veins due to their synergistic effects with each other.