Using photometric methods the antioxidant activity of 19 uracil derivatives has been analyzed. The test using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals can be applied for the rapid assessment of antioxidant activity of uracils. Among uracil derivatives studied the compounds possesing a proton-donor group in C-5 position--free or alkylated amino group, as well as hydroxyl group were the most active: 5-aminouracil (IC50 3 mg/ml), 5-amino-6-methyluracil (IC50 of 5 mg/ml), 5-hydroxy-6-methyluracil (IC50 of 15 mg/ml), 5-hydroxy-1,3,6-trimethyluracil (IC50 of 15 mg/ml), 5-ethylamino-6-methyluracil (IC50 of 20 mg/ml), 5-methylamino-6-methyluracil (IC50 of 20 mg/ml), 5-allylaminouracil (IC50 of 20 mg/ml), 5-amino-1,3,6- trimethyluracil (IC50 of 25 mg/ml). These uracil derivatives were more active than the reference compounds ionol (IC50 of 30 mg/ml) and a-naphthylamine (IC50 of 45 mg/ml), but less active than ascorbic acid (IC50 0.8 mg/ml). There was a correlation between the results of DPPH test (IC50) and coupling constants of uracil derivatives with peroxide radicals of 1,4-dioxane (fk7). Uracil with proton-donor group at C-5 also showed high ferrum-reducing activity as determined by FRAP.
Izuchena antioksidantnaia aktivnost' 19 proizvodnykh uratsila. Pokazano, chto test s ispol'zovaniem radikalov 2,2-difenil-1-pikrilgidrazila (DFPG) mozhet byt' primenen dlia ékspress-otsenki antioksidantnoĭ aktivnosti uratsilov. Sredi izuchennykh soedineniĭ naibol'shuiu aktivnost' pokazali proizvodnye uratsila s protonodonornoĭ gruppoĭ v polozhenii S-5 – svobodnoĭ ili alkilirovannoĭ aminogruppoĭ, a takzhe gidroksil'noĭ: 5-aminouratsil (IC 50 3 mkg/ml), 5-amino-6-metiluratsil (IC 50 5 mkg/ml), 5-gidroksi-6-metiluratsil (IC 50 15 mkg/ml), 5-gidroksi-1,3,6-trimetiluratsil (IC 50 15 mkg/ml), 5-étilamino-6-metiluratsil (IC 50 20 mkg/ml), 5-metilamino-6-metiluratsil (IC 50 20 mkg/ml),5-allilaminouratsil (IC 50 20 mkg/ml), 5-amino-1,3,6-trimetiluratsil (IC 50 25 mkg/ml). Dannye soedineniia okazalis' bolee aktivnymi, chem referentnye ionol (IC 50 30 mkg/ml) i a-naftilamin (IC 50 45 mkg/ml), no menee aktivny posravneniiu s askorbinovoĭ kislotoĭ (IC 50 0,8 mkg/ml).Ustanovlena korreliatsiia mezhdu rezul'tatami DFPG-testa (IC 50 ) i konstantami vzaimodeĭstviia proizvodnykh uratsila s peroksidnymi radikalami 1,4-dioksana (fk 7 ). Proizvodnye uratsila s protononodonornoĭ gruppoĭ pri S-5 proiavili takzhe vysokuiu zhelezovosstanavlivaiushchuiu aktivnost', opredelennuiu metodom FRAP.
Keywords: 2,2-diphenyl-1-picrylhydrazyl; antioxidant activity; ferrumrestoring capacity; uracil derivatives.