Captopril and 6-mercaptopurine: Whose SH possesses higher antioxidant ability?

Antioxidant capacities of captopril (CAP), 6-mercaptopurine (6-MP) and 9-(β-d-ribofuranosyl)-6-mercaptopurine (6-MPR) were investigated by interacting them with 2,2′-diphenyl-1-picrylhydrazyl (DPPH), galvinoxyl radical, and 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonate) cation radical (ABTS+), and by protecting DNA and erythrocyte against 2,2′-azobis(2-amidinopropane hydrochloride) (AAPH) induced oxidation. It was found that CAP possessed the highest ability to donate the hydrogen atom in –SH to DPPH and galvinoxyl, while 6-MPR had the strongest ability to reduce ABTS+. In the process of protecting DNA and erythrocytes against AAPH-induced oxidation, CAP can trap 0.5 and 1.3 radicals, 6-MP can trap 0.6 and 2.2, and 6-MPR can trap 1.0 and 3.0 radicals, respectively. CAP can also protect erythrocytes against hemin-induced hemolysis.

Antioxidant properties of captopril, 6-mercaptopurine and 9-(β-d-ribofuranosyl)-6-mercaptopurine were screened by protecting DNA and erythrocytes, and by interacting with radicals. The –SH group attached to aromatic ring possessed high antioxidant effectiveness.Figure optionsDownload as PowerPoint slide