Phenolic composition and related antioxidant properties in differently colored lettuces: a study by electron paramagnetic resonance (EPR) kinetics.
Differently colored lettuce (Lactuca sativa L.) cultivars (green, green/red, and red) were studied to correlate their phenolic composition with their antioxidant kinetic behavior. Electron paramagnetic resonance (EPR) was employed to monitor decay kinetics of 1,1-diphenyl-2-picrylhydrazyl (DPPH(•)), which allowed the identification of three differently paced antioxidants. The results showed that as long as lettuce had higher red pigmentation, the hydrophilic antioxidant capacity increased together with the contents in free and conjugated phenolic acids, free and conjugated flavonoids, and anthocyanins. EPR allowed the identification of slow-rate antioxidants in green and green/red cultivars, intermediate-rate antioxidants in green, green/red, and red cultivars, and fast-rate antioxidants in green/red and red cultivars. At present, the different kinetic behaviors cannot be attributed to a specific antioxidant, but it is suggested that the flavonoid quercetin accounted for the majority of the intermediate-rate antioxidants, whereas the anthocyanins accounted for the majority of the fast-rate antioxidants.
Departamento de Biologı́a Vegetal y Ecologı́a, Facultad de Ciencia y Tecnologı́a, Universidad del Paı́s Vasco , UPV/EHU, Apartado 644, E-48080 Bilbao, Spain.
Usue
U
Pérez-López
Calogero
C
Pinzino
Mike Frank
MF
Quartacci
Annamaria
A
Ranieri
Cristina
C
Sgherri
D000975:Antioxidants / Q000737:chemistry*; D004578:Electron Spin Resonance Spectroscopy / Q000379:methods*; D007700:Kinetics; D018545:Lactuca / Q000737:chemistry* / Q000145:classification; D010636:Phenols / Q000737:chemistry*; D010936:Plant Extracts / Q000737:chemistry*
D000975:Antioxidants; D010636:Phenols; D010936:Plant Extracts
ABTS•+; DPPH•; Lactuca sativa; anthocyanins; antioxidant capacity; electron paramagnetic resonance; flavonoids; phenolic acids