Next, we investigated the QUER and QU-CAP effects on cellular survival following oxidative stress and consequently on the intracellular ROS levels and the oxidative protein load. As shown in Fig. 4, cells that were treated with QUER or QU-CAP exhibited higher survival rates ranging from 5.4% to 7.5% as compared to the cells that were treated with the diluents. Additionally, cells that were treated with QUER or QU-CAP and were then subjected to oxidative stress exhibited a higher survival rate reaching to 14.5% as compared to the survival rate of the relative control cultures. In support, as shown in Fig. 5, we have observed reduced levels of both ROS and oxidized proteins following cell treatment with QUER or QU-CAP for 24 h under normal conditions or increased oxidative stress via H2O2-treatment. To this end, QUER and QU-CAP possess cytoprotective properties against oxidative stress.