ANTIOXIDATIVE EFFECTS OF TWO NATIVE BERRY SPECIES,EMPETRUM NIGRUMVAR. JAPONICUM K. KOCH ANDRUBUS BUERGERIMIQ., FROM THE JEJU ISLAND OF KOREA

Abstract

The extracts of two native berries from the Jeju Island of Korea were used to assess polyphenolics and flavonol levels, superoxide dismutase (SOD)-like enzyme activity, free radical scavenging activity, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide cell viability, protective effects against H2O2-induced cow pulmonary artery endothelium (CPAE) cell cytotoxicity and inhibition of low density lipoprotein (LDL) peroxidation. The total content of the flavonols and phenolic compounds in the leaves was higher than the fruit for both berries. In the free radical scavenging and SOD-like enzyme assay, all extracts showed strong antioxidative effects. The CPAE viability was greatly reduced and the survival rate was near 37% when the cells were treated with 1.0 mM H2O2 for 24 h. The extracts also inhibited lipid peroxidation in human LDL, measured as reduction in malondialdehyde production. The results showed that the leaf extracts of Empetrum nigrum significantly protected human LDL from Cu2+-induced oxidation. E. nigrum is suggested as an excellent potential source of natural antioxidants. PRACTICAL APPLICATIONS The results of these two Korean native berry species, especially Shiromi species, showed very strong effects on the inhibition of low density lipoprotein (LDL) oxidation and free radical scavenging. The LDL and free radicals have known close relations with coronary artery and cerebrovascular atherosclerosis. The antioxidative effects of these berries were stronger than existing commercial products. From these results, Korean native berry species might be very useful for the development of functional food for antioxidants preventing oxidative stress-related diseases like atherosclerosis. Making a new commercial product with Korean Shiromi berry will have good prospects.