MC4R and obesity disorder: Moreover, the compounds containing piperazine moiety were reported to have shown various biological activities in many studies [13,14] and, specifically, the Schiff bases derived from piperazine compounds have been described to demonstrate various biological activities; for example, anthelmintic [15], antimicrobial [16,17], acetylcholinesterase inhibition [18], melanocortin-4-receptor (MC4-R) [19,20], drug designer [21] anti-PAF [22,23], anti-HIV [24,25] and anti-obesity [26] activities.