Scavenging action of propolis extract against oxygen radicals

The ethanolic extracts of two types of cuban propolis (R and P) showed a similar manner of scavenging action against different species of oxygen radicals which were generated by specific chemical reactions. Chemiluminescence produced by superoxide generated from the xanthine-xanthine oxidase reaction was 50% inhibited by approximately 5 micrograms/ml of propolis R and 9.5 micrograms/ml of propolis P and by catechin (0.15 micrograms/ml) and superoxide dismutase (72 ng/ml). Alkoxy radical scavenging effect was similar to that produced by 0.11 micrograms/ml of alpha-tocopherol: inhibition of chemiluminescence by 50% was caused by approximately 0.6 micrograms/ml of both propolis preparations. The results indicate that the antioxidative properties of both propolis could be attributed to their free radical scavenging activity against alkoxy radicals and to a lesser degree against superoxide.