In this study, the effort was to design and synthesize five new members of alkoxy substituted thiourea derivatives (3a–3e) featuring general formula of A-ArC(O)NHC(S)NHAr-D in which A represents the methoxy group and D as –OCnH2n+1 (alkoxyl group, where n = 6,7,8,9, and 10) have been successfully designed, prepared, characterized, and evaluated for anti-amoebic activities. They were spectroscopically characterized by 1H and 13C Nuclear Magnetic Resonance (NMR), Fourier Transform Infrared (FT-IR) spectroscopy, and Ultraviolet–visible (UV–vis) spectroscopy analysis. In turn, they were used to investigate the cytotoxicity effect on Acanthamoeba sp. at their IC50 values and membrane permeability. Compounds 3a and 3b revealed to have good activity towards Acanthamoeba sp. compared to other compounds of 3c, 3d, and 3e. The observation under fluorescence microscopy by AOPI (Acridine-orange/Propidium iodide) staining indicated that treated amoeba cells by 3a–3e show loss of their membrane permeability.
