with a tissue grinder Kinematica (Crl-6010, Kriens-LU, Switzerland). For PPO and CAT assays, the extraction buffer was 50 mM sodium phosphate (pH 7.8). For POD, 100 mM sodium phosphate buffer (pH 6.4) was used The homogenate was centrifuged at 27,000 × g for 50 min at 4 ◦C and the resulting supernatants were used directly for assay