Preparation and antioxidant properties of extracts of Japanese persimmon leaf tea (kakinoha-cha)

摘要

Water and methanol extracts of persimmon leaf tea were studied for antioxidant and radical-scavenging activities. Antioxidant activity was measured using a β-carotene bleaching method. The activity of water extract was very strong and 0.125% higher than that of 10 mM ascorbic acid. The scavenging activity against superoxide anion radicals by methanol extract was stronger than that of the water extract, while 0.05% concentration of methanol extract showed about 50% inhibition. DPPH radical-scavenging activity of water and methanol extracts was strong, and 0.1% water extract showed more than 90% inhibition. The hydroxyl radical-scavenging activity of the extracts, at 1%, was nearly equal to that of 1 mM ascorbic acid. These results show that persimmon leaf tea could be considered as a natural antioxidant source.