The purpose of this study was to evaluate the antioxidant activity of Metaplexis japonica by using hot-water and ethanol extracts of its leaf and stem. Yields of hot-water and ethanol extracts of M. japonica leaf were high at 6.89 and 6.23%, respectively. The polyphenol and flavonoid contents in ethanol extracts of M. japonica leaf (ALEE) were high (86.96 and 60.73 mg/g, respectively). The electron-donating ability of all M. japonica extracts increased with an increase in extract concentration, with the highest electron-donating ability of 36.20~68.19% shown by hot-water extracts of M. japonica leaf (ALWE). The superoxide dismutase (SOD)-like activities of ALWE and ALEE increased with an increase in extract concentration. The nitrite-scavenging ability of the extracts was the highest at pH 1.2 and that of ALWE was higher than that of ALEE. The reducing power of 62.5 μg/mL ALEE was 0.09 and that of 1,000 μg/mL ALWE was 0.44. The inhibitory effect of an ethanol extract of M. japonica stem (ASEE) on tyrosinase was 13.81% at a concentration of 62.5 μg/mL and that of 1,000 μg/mL ALEE was 57.04%.

• Ju-Yeon Hong(Faculty of Herbal Food Cuisine and Nutrition, Daegu Haany University) | 홍주연
• Seung-Ryeul Shin(Faculty of Herbal Food Cuisine and Nutrition, Daegu Haany University) | 신승렬 Corresponding author