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A procedure to measure the antiradical efficiency of polyphenols
Author(s) -
SánchezMoreno Concepción,
Larrauri José A,
SauraCalixto Fulgencio
Publication year - 1998
Publication title -
journal of the science of food and agriculture
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.782
H-Index - 142
eISSN - 1097-0010
pISSN - 0022-5142
DOI - 10.1002/(sici)1097-0010(199802)76:2<270::aid-jsfa945>3.0.co;2-9
Subject(s) - dpph , chemistry , gallic acid , ascorbic acid , caffeic acid , rutin , tannic acid , antioxidant , ec50 , polyphenol , organic chemistry , chromatography , food science , biochemistry , in vitro
The kinetic behaviour of polyphenols common in fruits as free radical scavengers was studied using 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH • ). After addi‐tion of different standard concentrations to DPPH · (0·025 g litre −1 ), the percentage of remaining DPPH • was determined at different times from the absorbances at 515 nm. The percentage remaining DPPH • against reaction time followed a multiplicative model equation: ln [DPPH REM • ]= b ln t +ln a . The slopes of these equations may be useful parameters to define the antioxidant capacity. The steeper the slope, the lower the amount of antioxidant necessary to decrease by 50% the initial DPPH • concentration (EC 50 ). This parameter, EC 50 , is widely used to measure antioxidant power, but it does not takes into account the reaction time. Time needed to reach the steady state to the concentration corresponding at EC 50 ( T EC50 ) was calculated, and antiradical efficiency (AE) was proposed as a new parameter to characterise the antioxidant compounds where AE=1/EC 50 T EC50 . It was shown that AE is more discriminatory than EC 50 . AE values are more useful because they also take into account the reaction time. The results have shown that the order of the AE (×10 −3 ) in the compounds tested was: ascorbic acid (11·44)>caffeic acid (2·75)⩾gallic acid (2·62)>tannic acid (0·57)⩾ DL ‐α‐tocopherol (0·52)>rutin (0·21)⩾quercetin (0·19)>ferulic acid (0·12)⩾3‐ tert ‐butyl‐4‐hydroxyanisole, BHA (0·10)>resveratrol (0·05). © 1998 SCI.