HYDROXYL AND SUPEROXIDE ANION-RADICAL SCAVENGING ACTIVITIES OF NATURAL SOURCE ANTIOXIDANTS USING THE COMPUTERIZED JES-FR30 ESR SPECTROMETERSYSTEM

Free radical scavenging activities of water-soluble extracts from some natural sources, health foods, and antioxidant substances were measur ed using the JES-FR30 JEOL spectrometer. The objective was to develop a standardized method whereby comparison could be made between the rad ical scavenging activities of complex mixtures. Scavenging of hydroxyl radical was determined using DMPO. Activity was calibrated using a st andard material, L-ascorbic acid 12-trimethyltridecyl)-2H-1-benzopyran -6yl-hydrogen phosphate] potassium salt (EPC-K-1), an analog of vitami n C and vitamin E which is water soluble and stable at room temperatur e. The order of greatest hydroxyl radical scavenging activity was gree n tea extract, pine bark extract (Pycnogenol), Ginkgo Biloba extract ( EGb 761), a flavonoid blend of several fruit and vegetable extracts (G NLD), and Bio-Normalizer (Sun-O Corp). Activity was determined after t reatment of samples with ascorbic acid oxidase. This treatment reveale d the presence of ascorbate in some natural extracts and commercial pr eparations. The pine bark extract was the most heat resistant and had ascorbate-like activity in the preparations. Scavenging of superoxide anion was determined using the spin trap, 5,5-dimethyl-1-pyrroline-N-o xide (DMPO), and analyzed by comparison with a standard curve made wit h superoxide dismutase. Comparison of the water solubilized components of natural source antioxidants showed that filtrates fractionated usi ng centrifuge type Millipore filter tubes (M.W.<100,000; M.W.<10,000) also had almost the same SOD-like activity. Samples were also treated with ascorbate oxidase or by heating (100 degrees C for 10 min). The o rder of activity, from greatest to least, was Ginkgo biloba extract EG b 761, pycnogenol, beta-catechin, tea and BioNormalizer.