Free Radical Scavenging Properties of Conjugated Linoleic Acids

Abstract

Conjugated linoleic acids (CLA) were investigated for free radical scavenging properties against the stable 2,2-diphenyl-1-picryhydrazyl radical (DPPH.) by electron spin resonance (ESR) spectrometry and spectrophotometric methods. ESR results demonstrated that CLA directly reacted and quenched free DPPH radicals in benzene, while spectrophotometric analysis showed the radical scavenging capacity of CLA in ethanol. Dose and time effects of CLA-DPPH. reactions were observed in both tests. The ED(50) of CLA was 18 mg/mL under experimental conditions. CLA are much weaker radical scavengers as compared to vitamin E, vitamin C, and BHT. Kinetics of CLA-DPPH. reactions was different to that of linoleic acid (LA)-DPPH. reactions. CLA reacted and quenched DPPH radicals at all tested levels without a lag phase, while LA had a lag phase and showed no radical quenching activity at levels of 5-80 mg/mL in 30 min. These data indicated that CLA can provide immediate protection against free radicals, but LA cannot.

Genesis and development of DPPH method of antioxidant assay

“…This method is easy and applies to measure the overall antioxidant capacity (Prakash 2001) and the free radical scavenging activity of fruit and vegetable juices (Sendra et al 2006). This assay has been successfully utilized for investigating antioxidant properties of wheat grain and bran, vegetables, conjugated linoleic acids, herbs, edible seed oils, and flours in several different solvent systems including ethanol, aqueous acetone, methanol, aqueous alcohol and benzene (Yu 2001;Parry et al 2005). It is a convenient method for the antioxidant assay of cysteine, glutathione, ascorbic acid, tocopherol and polyhydroxy aromatic compounds (Masahiro et al 2005), for olive oil, fruits, juices and wines (Sanchez-Moreno 2002).…”

Effects of dietary conjugated linoleic acid on the duodenal mucosal immunity response and redox status of broiler chicks infected with Eimeria aceruvlina

“…Dietary CLA reduced the proportion of macrophages in the mouse mesenteric lymph, inhibited the expression of colonic TNFα, and prevented the colon cancer development induced by inflammation (Evans et al 2010). Moreover, some studies have revealed the antioxidant properties of CLA (van Den Berg et al 1995;Yu 2001). For instance, in rat and chicken, CLA could alleviate doi: 10.17221/8850-CJAS oxidative damages induced by inflammatory agents such as the lipopolysaccharide, gliadin, and sodium arsenite (Zhang et al 2008;Bergamo et al 2011).…”

Antifungal, Nematicidal and Antioxidant Activity of the Methanol Extracts Obtained from Medicinal Plants

“…It is a commercial oxidising radical, which can be reduced by antioxidants. The stable DPPH can be used to study the reaction kinetics of antioxidants, as well as to quantify and compare the free radical scavenging capacities of different antioxidants (Yu, 2001). Fig.…”