Synthesis of Known and New 8-Hydroxyquinoline Mannich Bases and Determination of Their Significant Biological Activities.

Use of 10 different combinations of aldehydes and amines to carry out the Mannich reaction on 8-hydroxyquinoline generated 11 compounds including Mannich bases and imines, 6 of which are new while 5 are known. Their structures were characterized by mass spectroscopy, 1HNMR, 13CNMR including 2D, IR, and EI analysis. Upon screening for their antimicrobial activities, oxidative burst (of whole blood phagocytes, isolated neutrophils and macrophages), on T-cell proliferation, antioxidant and cytotoxic activities, compound 4 (7-[α-(2″,5″-dichloroanilinobenzyl]-8-hydroxyquinoline) a new Mannich base, was found to possess antimicrobial property, immunomodulating potential on chemiluminescence assays, suppressed T-cells and exhibited no cytotoxicity. This novel compound upon in vivo histopathological examination on BALB/c mice showed unaffected kidneys at any of the tested concentration (1.3, 6.67, 33.33, and 166.67 mg/kg), while at different concentrations were found to be cardio-toxic and hepatotoxic. Furthermore, molecular docking simulations determined the probable binding modes of these compounds to their targets.