CiteWeb id: 19950000048

CiteWeb score: 7260

DOI: 10.1016/S0023-6438(95)80008-5

Tile antiradical activities of various antioxidants were determined using the free radical, 2.2-Diphenyl-l-pict3,1hydrazyl (DPPI-I°). In its radical form, DPPI-I ° has an absorption band at 515 nm which disappears upon reduction by an antiradical compound. Twenty compounds were reacted with the DPPI-I ° and shown to follow one of three possible reaction kinetic types. Ascorbie acid, isoascorbic acid and isoeugenol reacted quickly with the DPPI-I ° reaching a steady state immediately. Rosmarinic acid and 6-tocopherol reacted a little slower and reached a steady state within 30 rain. The remaining compounds reacted more progressively with the DPPH ° reaching a steady state from I to 6 h. Caffeic acid, gentisic acid and gallic acid showed the highest antiradical activities with a stoichiometo, of 4 to 6 reduced DPPH ° molecules pet" molecule of antioxidant. Vanillin, phenol, y-resort3'lic acid and vanillic acid were found to be poor antiradical compounds. The stoichiometry, for the other 13 phenolic compounds varied from one to three reduced DPPH ° molecules pet" molecule of antioxidant. Possible mechanisms are proposed to explain the e.werimental results.