IN Vitro Xanthine Oxidase Inhibitory Activity of Spiny Pigweed (Amaranthus spinosus Linn.) Leaves Crude EXTRACT

Abstract

Hyperuricemia (HUA), marked by elevated xanthine oxidase (XO) activity, is significantly linked to gout and various metabolic disorders. Since XO is a key enzyme in uric acid formation, it serves as a primary target for therapeutic interventions. This study aimed to evaluate the in vitro xanthine oxidase inhibitory activity of the spiny pigweed (Amaranthus spinosus Linn.) leaves crude extract. An experimental research design was employed where the XO inhibitory activity was assessed using a spectrophotometric method by measuring uric acid formation from a xanthine substrate. Ethanolic crude extracts at concentrations of 200, 100, 50, 25, 12.5, and 1 µg/mL were tested, with allopurinol serving as the standard reference at the same concentration levels. Qualitative phytochemical screening confirmed the presence of flavonoids, saponins, terpenoids and glycosides. A. spinosus leaves crude extract exhibits a high percentage of xanthine oxidase inhibitory activity—achieving 96.37% inhibition at 200 µg/mL—with an IC₅₀ value of 1.912 µg/mL determined using probit analysis, suggesting notable therapeutic potential as an XO inhibitor. Total flavonoid and total phenolic content results reveal an average amount of 446.258 mcg QE/g and 536.951 mcg GAE/g of crude extract, respectively. The diverse compounds present contribute significantly to the effective XO inhibitory activity of A. spinosus.