ESR SPECTROSCOPIC STUDIES ON FREE-RADICAL QUENCHING ACTION OF FINGER MILLET (ELEUSINE-CORACANA)

The free radical quenching action of finger millet (Eleusine coracana) on 1,1'-diphenyl-2-picrylhydrazyl (5.407 x 10(17) spins/ml(-1)) and h ydroxyl (0.6015 x 10(15) spins /ml(-1)) radicals was studied by electr on spin resonance (ESR) spectrometry. A 10 ml concentrate of the metha nol extract was prepared using 25 g of the cereal grains and all analy sis done after 1:10 dilution. DPPH radical quenching with 50 mu l of t he extracts showed that the brown finger millet quenched 94% whereas t he white finger millet quenched only 4%. The phenolic content of brown finger millet was 96% higher than the white variety. Processing of th e brown finger millet by germination and/or fermentation decreased the quenching activity. In comparison, foxtail millet, pearl millet and s orghum, quenched 91, 59 and 52 percent respectively, while wheat, rice (dehusked) and rice husk quenched 18, 1.8 and 20% respectively. Brown finger millet (50 mu l) also quenched 77% of hydroxyl radicals. The r esults indicate that finger millet is a potent source of antioxidant c ompounds. Copyright (C) 1996 Elsevier Science Ltd