A procedure to measure the antiradical efficiency of polyphenols

✍ Scribed by Sánchez-Moreno, Concepción; Larrauri, José A; Saura-Calixto, Fulgencio

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 283 KB
• Volume: 76
• Category: Article
• ISSN: 0022-5142
• DOI: 10.1002/(sici)1097-0010(199802)76:2<270::aid-jsfa945>3.0.co;2-9

✦ Synopsis

The kinetic behaviour of polyphenols common in fruits as free radical scavengers was studied using 2,2-diphenyl-1-picrylhydrazyl After addi-(DPPH~). tion of di †erent standard concentrations to DPPHÕ (0É025 g litre~1), the percentage of remaining was determined at di †erent times from the absorb-DPPHã nces at 515 nm. The percentage remaining against reaction time DPPHf ollowed a multiplicative model equation : The ln [DPPH REM ~]\b ln t ] ln a. slopes of these equations may be useful parameters to deÐne the antioxidant capacity. The steeper the slope, the lower the amount of antioxidant necessary to decrease by 50% the initial concentration This parameter, DPPH~(EC 50 ). 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 was calculated, and antiradical efficiency (AE) was EC 50 (T EC50 ) proposed as a new parameter to characterise the antioxidant compounds where It was shown that AE is more discriminatory than AE \ 1/EC 50 T EC50 . E C 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 (11É44) [ ca †eic acid (2É75) P gallic acid (2É62) [ tannic acid (0É57) P DL-a-tocopherol (0É52) [ rutin (0É21) P quercetin (0É19) [ ferulic acid (0É12) P 3-tert-butyl-4-hydroxyanisole, BHA (0É10) [ resveratrol (0É05).

1998 SCI.