MARCHANTINS AND RELATED POLYPHENOLS FROM LIVERWORT - PHYSICOCHEMICAL STUDIES OF THEIR RADICAL-SCAVENGING PROPERTIES

Structurally unique macrocyclic phenols from liverwort, i.e., marchant ins and related substances, were studied for their antioxidative poten tial using pulse-radiolytic and EPR-spectroscopic techniques. The gene rally diffusion-controlled rate constants for scavenging of azide radi cals as a model electrophilic species and the sufficiently slow bimole cular decay confirm their antioxidative potential. Transient spectra a fter pulse radiolysis and the EPR spectra both demonstrate the interna l strain of the macrocyclic ring. One compound, Perrottetin D, further more gave proof to the hitherto only kinetically verifyable superior r adical-scavenging capability of the aroxyl radical derived from a phen olic antioxidant.