Effect of pre-treatment and extraction conditions on the antioxidant properties of persimmon (Diospyros kaki) leaves

Persimmon is a very delicious fruit and the leaves of this tree are used as a traditional drug. This study aimed to investigate the effects of drying method (hot air and freeze-drying), extraction temperature (80, 90 and 100 °C) and extraction time (10, 30, 60 and 120 min) and harvest stage (flowering and fruiting) on the antioxidant contents and antioxidant activity of persimmon leaves. The results showed that the highest antioxidants were obtained in both methods of drying. Also, 100 °C for 120 min of extraction gave the highest antioxidant contents, but with no significant difference compared to 90 °C for 60 min of extraction. Persimmon leaves collected during flowering stage had the maximum amount of antioxidants compared to the fruiting stage. Finally, it can be said that persimmon leaves harvested during flowering stage and treated by hot air drying with these extraction conditions (90 °C for 60 min) are richer in bioactive compounds.