Radical-scavenging activities of marine-derived xyloketals and related chromanes

Abstract

Xyloketals, a new type of antioxidants from a marine mangrove fungus, have potential pharmacological properties. In this paper, the radical-scavenging activities of a series of synthetic xyloketals and related chromanes toward 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) were evaluated by absorption spectrometry. One of the compounds (compound 10) displayed significant antioxidative action against DPPH and ABTS. A structure-activity analysis showed that the reactive sites on these compounds correlated with a hydroxy-group and also with ketal or aromatic H substituents. Based in part on a density functional theory (DFT) calculation of compound 10, the antioxidant mechanism of this chromane was deduced as a possible radical-scavenging mechanism by a sequential proton loss electron-transfer (SPLET) process.

Keywords

• Xyloketals
• Radical scavenging activities
• DFT
• SPLET