Author(s): Johnson Preethi, Loganathan Chitra and Thayumanavan Palvannan

Abstract: The medicinal plant Cardiospermum halicacabum (C. halicacabum) has multiple beneficial effects known for its rheumatism. The positive effect of aqueous leaf C. halicacabum extract (ALCHE) against xanthine oxidase (XO) inhibition has not been studied. The present study aims to depict the effect of ALCHE: (1) antioxidant effect; (2) in vitro XO enzyme inhibition and (3) in vivo anti-hyperuricemic effect using Bombyx mori L. (B.mori) model. In vitroantioxidant scavenging and XO enzyme inhibition was determined using ALCHE.In vivo B.mori model was used to evaluate the effect of ALCHE against anti-hyperuricemia for 5 days. B.mori was treated with ALCHE and allopurinol (5 mg/ml) coated fresh mulberry leaves. After the treatment, XO activity and uric acid were determined in the hemolymph of the B.mori. ALCHE showed higher antioxidant activity in comparison to ascorbic acid. ALCHE inhibited the XO enzyme (IC₅₀ value, 28 μg/ml) in a competitively with a Ki value of 2.8 μg/ml. The XO enzyme inhibition by ALCHE was further confirmed by in vivo B.mori model, it shows the better reduction of uric acid, due to the presence of phenolic antioxidants which inhibits the pro-oxidant enzyme such as XO.