Lactoperoxidase and Xanthine Oxidase Inhibition Potential of Endemic Taraxacum mirabile Wagenitz Plant Extract: A Comparative Analysis In Vitro

Taraxacum mirabile Wagenitz, one of the endemic riches of Anatolia, is a species that has remained largely unexplored regarding its enzyme inhibition profile despite its pharmacological potential. The effects of T. mirabile aerial and root extracts, obtained at different polarities, were scrutinized in this study against two important enzymes: lactoperoxidase (LPO), which plays a vital role in the innate immune system, and xanthine oxidase (XO), which is prominently associated with hyperuricemia and oxidative stress. The aerial and root portions of the plant were extracted into fractions of varying polarities using petroleum ether, dichloromethane, ethyl acetate, and butanol. LPO was isolated from buffalo milk (881.6-fold purification, 22.5% yield, and 1249.9 EU/mg specific activity) via affinity chromatography and used in in vitro inhibition assays alongside commercial bovine XO enzyme. The results showed that the ethyl acetate fraction of the aerial part of the plant exhibited the strongest LPO inhibition (IC50: 15.60 ± 0.77 µg/mL) among the fractions. The petroleum ether fraction of both the aerial part (IC50: 11.17 ± 0.94 µg/mL) and the root part (IC50: 11.61 ± 0.59 µg/mL) had the highest inhibitory effect for the XO enzyme. These distinct inhibition profiles allow for significant insights into how plant extracts with varying polarities modulate XO and LPO enzymes. In conclusion, the significant inhibitory activity of T. mirabile extracts toward LPO and XO enzymes highlights their potential as a natural source for developing effective enzyme inhibitors, which could be useful for therapeutic applications.