INS and metabolic syndrome: The activities are due to reduction in ROS generation, direct superoxide scavenging, protection of NO signaling, etc. For example, DCI may be considered a therapeutic agent against metabolic syndrome, endothelial dysfunction, and erectile dysfunction in diabetes patients (Nacimento et al., 2006), and MI may act as alternative of metformin, the most popular oral antidiabetic drug, because it interacts directly with insulin target tissues; however, it does not show the side effects of the drug (Dona et al., 2012).