HPLC analysis, antioxidant, anti-inflammatory and xanthine oxidase inhibitory activity of Cudrania tricuspidata

Abstract

Cudrania tricuspidata is a plant used in folk medicine in Korea for treatment of diseases related to oxidative stress and inflammation. In this study the leaf and shoot extract was studied for its antioxidant, anti-inflammatory, and xanthine oxidase (XO) inhibitory activities. The extract with predominant phenolics was quantified using HPLC-DAD. Antioxidant activity was measured using ABTS [2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) and FRAP (ferric ion reducing antioxidant power), and anti-inflammatory activity by diene-conjugate and β-glucuronidase assays. The average antioxidant effects of C. tricuspidata extracts (1-2 mg/mL) revealed significant activity of 32.5% to 50.2% (ABTS) and 24.2 to 40.5% (FRAP) compared with Trolox, having 55.1% (ABTS) and 42.6% (FRAP) activity, respectively. The anti-inflammatory activities showed as 26.5% to 40.5% (DC) and 40.2% to 70.2% (βG) inhibition compared with the control {phenylbutazone; 42.1% (DC) and 80.2% (βG) inhibition, respectively}. The XO inhibitory activity of the plant extract revealed 90.5% inhibition of that of the control (allopurinol) (97% inhibition at 100 μg/mL concentration). The kinetic parameters of XO inhibition revealed a noncompetitive type of inhibition, where, Kmand Vmax of C. tricuspidata extracts (25 to 100 μg/mL) were 0.25 mM/mL and 0.040, 0.036, 0.032, and 0.030 (μg/min), while for the positive control Km and Vmax the values were 0.30 mM/mL and 0.045 (μg/min), respectively. Results suggest that C. tricuspidata can be exploited against diseases associated with free radical formation and xanthine oxidase activity.