title: The role of cyclodextrins in ORAC-fluorescence assays. antioxidant capacity of tyrosol and caffeic acid with hydroxypropyl-β-cyclodextrin.
abstract: Tyrosol and caffeic acid are biophenols that contribute to the beneficial properties of virgin olive oil. The influence of hydroxypropyl-β-cyclodextrin (HPβ-CD) on their respective antioxidant capacities was analyzed. The ORAC antioxidant activity of tyrosol (expressed as μM Trolox equivalents/μM Tyrosol) was 0.83 ± 0.03 and it increased up to 1.20 ± 0.11 in the presence of 0.8 mM HPβ-CD. However, the ORAC antioxidant activity of caffeic acid experienced no change. The different effect of HPβ-CD on each compound was discussed. In addition, the effect of increasing concentrations of different cyclodextrins in the development of ORAC-fluorescence (ORAC-FL) assays was studied. The ORAC signal was higher for HPβ-CD, followed by Mβ-CD, β-CD, γ-CD and finally α-CD. These results could be explained by the formation of inclusion complexes with fluorescein.
authors.affiliation: Departamento de Química y Edafología, Facultad de Ciencias, University of Navarra , Irunlarrea s/n, Pamplona 31080, Navarra, Spain.
authors.forename: Marcos
authors.initials: M
authors.lastname: García-Padial
authors.forename: María Cristina
authors.initials: MC
authors.lastname: Martínez-Ohárriz
authors.forename: Iñigo
authors.initials: I
authors.lastname: Navarro-Blasco
authors.forename: Arantza
authors.initials: A
authors.lastname: Zornoza
mesh_terms: D000073738:2-Hydroxypropyl-beta-cyclodextrin; D000975:Antioxidants / Q000032:analysis*; D002109:Caffeic Acids / Q000032:analysis*; D003505:Cyclodextrins / Q000737:chemistry*; D010626:Phenylethyl Alcohol / Q000031:analogs & derivatives* / Q000032:analysis; D013050:Spectrometry, Fluorescence / Q000379:methods*; D047392:beta-Cyclodextrins / Q000737:chemistry*
chemical_list: D000975:Antioxidants; D002109:Caffeic Acids; D003505:Cyclodextrins; D047392:beta-Cyclodextrins; C011867:4-hydroxyphenylethanol; D000073738:2-Hydroxypropyl-beta-cyclodextrin; D010626:Phenylethyl Alcohol; C040048:caffeic acid