Reactive oxygen species scavenging activity of Du-zhong (Eucommia ulmoides oliv.) and its active compounds.

The biologically active compounds and free radical-/ or reactive oxygen species (ROS)-/ scavenging effect of water extract from Du-zhong (WEDZ) were investigated. The WEDZ used included leaves, raw cortex, and roasted cortex. The hot water extract of Du-zhong leaves showed marked activity as a ROS scavenger, and the scavenging effect was concentration dependent. The extract of roasted cortex exhibited a modest scavenging effect on ROS, while the extract of raw cortex had the weakest scavenging effect. The scavenging activity of WEDZ on ROS was correlated to its protocatechuic acid (PCA) content. The content of PCA in Du-zhong determined by HPLC followed the order of leaves (17.17 mg/g) > roasted cortex (2.99 mg/g) > raw cortex (1.16 mg/g). The inhibitory activity of leaf extract of Du-zhong was stronger than that of PCA on the peroxidation of linoleic acid at the same concentration of 0.1 mg/mL. The results presented herein indicated that extract of Du-zhong could possibly act as a prophylactic agent to prevent free radical-related diseases.