Peroxidation of linoleic acid was initiated by azobis (isobutyronitrile) in ethanol and inhibited effectively by alizarin and β-carotene. it was found alizarin and β-carotene either alone or in combination exhibited obvious inhibiting effect, and the decay of β-carotene slowed down in the presence of alizarin. Quantitative kinetic measurement showed alizarin and β-carotene can act as free radical inhibitors for bulk free radical polymerization of styrene initiated by AIBN at 60℃. The experimental results indicated that their synergistic efficiency depended on the amount of alizarin and β-carotene used. the effect of alizarin and acetylcholine on endothelial cell release of nitric oxide in human umbilical vein was also observed. The alizarin exhibits a more efficiency release of nitric oxide that of acetylcholine.

Key words: ALIZARINE, CAROTENE, ANTIOXIDANTS, NITROGEN MONOXIDE, RELEASE, FREE RADICALS, SYNERGISTIC EFFECT