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Oxygen radical absorbance capacity (ORAC) of cyclodextrin-solubilized flavonoids, resveratrol and astaxanthin as measured with the ORAC-EPR method.

Sueishi Y, Ishikawa M, Yoshioka D, Endoh N, Oowada S, Shimmei M, Fujii H, Kotake Y - J Clin Biochem Nutr (2011)

Bottom Line: The results indicated that the agreement between spin trapping-based and fluorescence-based values was only fair partly because of a large variation in the previous fluorescence-based data.Typical radical scavenging abilities in trolox equivalent unit are: catechin 0.96; epicatechin 0.94; epigallocatechin gallate 1.3; kaempferol 0.37; myricetin 3.2; resveratrol 0.64; and astaxanthin 0.28, indicating that myricetin possesses the highest antioxidant capacity among the compounds tested.We sorted out the possible causes of the deviation between the two methods.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemistry, Faculty of Science, Okayama University, 3-1-1 Tsushima-naka, Kita-ku, Okayama 700-8530, Japan.

ABSTRACT
Recently, we proposed an oxygen radical absorbance capacity method that directly quantifies the antioxidant's scavenging capacity against free radicals and evaluated the radical scavenging abilities for water soluble antioxidant compounds. In this study, we determined the radical scavenging abilities of lipophilic antioxidants which were solubilized by cyclodextrin in water. Commonly employed fluorescence-based method measures the antioxidant's protection capability for the fluorescent probe, while we directly quantify free-radical level using electron paramagnetic resonance spin trapping technique. In addition, the spin trapping-based method adopted controlled UV-photolysis of azo-initiator for free radical generation, but in fluorescence-based method, thermal decomposition of azo-initiator was utilized. We determined the radical scavenging abilities of seven well-known lipophilic antioxidants (five flavonoids, resveratrol and astaxanthin), using methylated β-cyclodextrin as a solubilizer. The results indicated that the agreement between spin trapping-based and fluorescence-based values was only fair partly because of a large variation in the previous fluorescence-based data. Typical radical scavenging abilities in trolox equivalent unit are: catechin 0.96; epicatechin 0.94; epigallocatechin gallate 1.3; kaempferol 0.37; myricetin 3.2; resveratrol 0.64; and astaxanthin 0.28, indicating that myricetin possesses the highest antioxidant capacity among the compounds tested. We sorted out the possible causes of the deviation between the two methods.

No MeSH data available.


Related in: MedlinePlus

Structures of 2,6-di-O-methylated β-CD (DM-β-CD), CYPMPO, AAPH, and antioxidants.
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Related In: Results  -  Collection


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Figure 1: Structures of 2,6-di-O-methylated β-CD (DM-β-CD), CYPMPO, AAPH, and antioxidants.

Mentions: Both ORAC-FL and ORAC-EPR are water-based methods; however, a majority of antioxidants are classified as lipophilic compounds such as flavonoids. The poor solubilization or dispersion of antioxidants could lead to poor assay validity.(15,16) In ORAC-FL, Huang et al.(17) proposed the use of modified β-cyclodextrin to solubilize lipophilic compounds. β-Cyclodextrin (β-CD) is a cyclic hexamer of glucose units having a molecular cavity (see structure in Fig. 1), wherein a lipophilic molecule is encapsulated or included to form water-soluble inclusion complex. Such peculiar properties of β-CD have been found to be useful in industrial and domestic applications, such as drug-solubilizers and deodorizers.(18–20)


Oxygen radical absorbance capacity (ORAC) of cyclodextrin-solubilized flavonoids, resveratrol and astaxanthin as measured with the ORAC-EPR method.

Sueishi Y, Ishikawa M, Yoshioka D, Endoh N, Oowada S, Shimmei M, Fujii H, Kotake Y - J Clin Biochem Nutr (2011)

Structures of 2,6-di-O-methylated β-CD (DM-β-CD), CYPMPO, AAPH, and antioxidants.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3299942&req=5

Figure 1: Structures of 2,6-di-O-methylated β-CD (DM-β-CD), CYPMPO, AAPH, and antioxidants.
Mentions: Both ORAC-FL and ORAC-EPR are water-based methods; however, a majority of antioxidants are classified as lipophilic compounds such as flavonoids. The poor solubilization or dispersion of antioxidants could lead to poor assay validity.(15,16) In ORAC-FL, Huang et al.(17) proposed the use of modified β-cyclodextrin to solubilize lipophilic compounds. β-Cyclodextrin (β-CD) is a cyclic hexamer of glucose units having a molecular cavity (see structure in Fig. 1), wherein a lipophilic molecule is encapsulated or included to form water-soluble inclusion complex. Such peculiar properties of β-CD have been found to be useful in industrial and domestic applications, such as drug-solubilizers and deodorizers.(18–20)

Bottom Line: The results indicated that the agreement between spin trapping-based and fluorescence-based values was only fair partly because of a large variation in the previous fluorescence-based data.Typical radical scavenging abilities in trolox equivalent unit are: catechin 0.96; epicatechin 0.94; epigallocatechin gallate 1.3; kaempferol 0.37; myricetin 3.2; resveratrol 0.64; and astaxanthin 0.28, indicating that myricetin possesses the highest antioxidant capacity among the compounds tested.We sorted out the possible causes of the deviation between the two methods.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemistry, Faculty of Science, Okayama University, 3-1-1 Tsushima-naka, Kita-ku, Okayama 700-8530, Japan.

ABSTRACT
Recently, we proposed an oxygen radical absorbance capacity method that directly quantifies the antioxidant's scavenging capacity against free radicals and evaluated the radical scavenging abilities for water soluble antioxidant compounds. In this study, we determined the radical scavenging abilities of lipophilic antioxidants which were solubilized by cyclodextrin in water. Commonly employed fluorescence-based method measures the antioxidant's protection capability for the fluorescent probe, while we directly quantify free-radical level using electron paramagnetic resonance spin trapping technique. In addition, the spin trapping-based method adopted controlled UV-photolysis of azo-initiator for free radical generation, but in fluorescence-based method, thermal decomposition of azo-initiator was utilized. We determined the radical scavenging abilities of seven well-known lipophilic antioxidants (five flavonoids, resveratrol and astaxanthin), using methylated β-cyclodextrin as a solubilizer. The results indicated that the agreement between spin trapping-based and fluorescence-based values was only fair partly because of a large variation in the previous fluorescence-based data. Typical radical scavenging abilities in trolox equivalent unit are: catechin 0.96; epicatechin 0.94; epigallocatechin gallate 1.3; kaempferol 0.37; myricetin 3.2; resveratrol 0.64; and astaxanthin 0.28, indicating that myricetin possesses the highest antioxidant capacity among the compounds tested. We sorted out the possible causes of the deviation between the two methods.

No MeSH data available.


Related in: MedlinePlus