Comparison of the antioxidant action of the alcoholic extract of Rubia cordifolia with rubiadin.

The inhibition of FeSO4 induced lipid peroxidation in rat liver by alcoholic extract of Rubia cordifolia and by one of its constituent rubiadin (1, 3-dihydroxy-2-methyl anthraquinone) (pure form) has been compared. Both have been found to inhibit lipid peroxidation in a dose dependent manner. Whereas the former shows both oxidising and reducing properties with Fe2+ and Fe3+, the latter shows oxidising property only by converting Fe2+ to Fe3+. The former inhibits the oxidation of reduced glutathione while the latter does not.