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Contribution of major lipophilic antioxidants to the antioxidant activity of basil extracts: an EPR study
Author(s) -
Sgherri Cristina,
Pinzino Calogero,
NavariIzzo Flavia,
Izzo Riccardo
Publication year - 2011
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/jsfa.4296
Subject(s) - dpph , chemistry , antioxidant , carotenoid , tocopherol , chlorophyll , electron paramagnetic resonance , food science , kinetics , lutein , botany , organic chemistry , vitamin e , nuclear magnetic resonance , biology , physics , quantum mechanics
BACKGROUND: The present research analyses the contribution of some lipid antioxidants to the antioxidant activity of lipophilic extracts from basil by an electron paramagnetic resonance (EPR) study using the stable free radical 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH). DPPH assay is considered an easy and accurate method with regard to measuring the antioxidant activity of plant extracts and EPR has already been employed to determine antioxidant activities of lipophilic plant extracts. RESULTS: Lipid extracts were obtained from basil grown hydroponically for 20 or 35 days from sowing and in soil for 35 days from sowing. Fast and slow rate constants were distinguishable in the decay kinetics of DPPH mixture added with lipid extract. Antioxidants with kinetics characterized by a fast decay rate were tocopherols and chlorophylls, whereas those characterized by a slow decay rate were carotenoids, among which were β‐carotene, lutein, β‐apo‐8′‐carotenal and zeaxanthin. The 20‐day hydroponically grown sample, which showed higher contents of tocopherol, chlorophyll and carotenoid molecules, was the sample endowed with the higher content of fast lipophilic antioxidants (FLA) and slow lipophilic antioxidants (SLA). CONCLUSION: The three samples showed different compositions of FLA and SLA, giving rise to different decay kinetics. Despite the differences, in all samples tocopherol contributed about 0.3% to the bulk of FLA, whereas the figure for chlorophyll was about 40%, evidencing the relevant but little‐studied role of chlorophyll as an antioxidant. Copyright © 2011 Society of Chemical Industry