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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.


A typical plot of (I0–I)/I of catechin (CA) against [AOx]0/[ST]0 in the presence of DM-β-CD using Eq. 1 (AOx = CA and ST = CYPMPO). I0 is taken from the EPR peak height such as shown in Fig. 2a and I from Fig. 2b. The slope kAOx/kST (approximately 92 in this graph) corresponds to the ORAC-EPR value of CA relative to CYPMPO.
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Figure 3: A typical plot of (I0–I)/I of catechin (CA) against [AOx]0/[ST]0 in the presence of DM-β-CD using Eq. 1 (AOx = CA and ST = CYPMPO). I0 is taken from the EPR peak height such as shown in Fig. 2a and I from Fig. 2b. The slope kAOx/kST (approximately 92 in this graph) corresponds to the ORAC-EPR value of CA relative to CYPMPO.

Mentions: Fig. 3 shows a typical plot for Eq. 1 in CA/CYPMPO system in the presence of DM-β-CD, the slope of which demonstrates CA’s ORAC value relative to CYPMPO. The plot of the relative radical scavenging rates gives a straight line that passes through the origin, indicating that the reaction scheme and the calculation procedures of relative radical scavenging rate constants (kAOx/kST) using Eq. 1 are justified. Using similar procedures, ORAC-EPR values (kAOx/kST) relative to CYPMPO for seven lipophilic antioxidants were calculated and converted into trolox equivalent unit. Average ORAC-values after five repeated measurements are shown in Table 1 and Fig. 4 with standard deviation. Previous ORAC-FL data are also listed in Table 1 and Fig. 4.(10,30–35)


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)

A typical plot of (I0–I)/I of catechin (CA) against [AOx]0/[ST]0 in the presence of DM-β-CD using Eq. 1 (AOx = CA and ST = CYPMPO). I0 is taken from the EPR peak height such as shown in Fig. 2a and I from Fig. 2b. The slope kAOx/kST (approximately 92 in this graph) corresponds to the ORAC-EPR value of CA relative to CYPMPO.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 3: A typical plot of (I0–I)/I of catechin (CA) against [AOx]0/[ST]0 in the presence of DM-β-CD using Eq. 1 (AOx = CA and ST = CYPMPO). I0 is taken from the EPR peak height such as shown in Fig. 2a and I from Fig. 2b. The slope kAOx/kST (approximately 92 in this graph) corresponds to the ORAC-EPR value of CA relative to CYPMPO.
Mentions: Fig. 3 shows a typical plot for Eq. 1 in CA/CYPMPO system in the presence of DM-β-CD, the slope of which demonstrates CA’s ORAC value relative to CYPMPO. The plot of the relative radical scavenging rates gives a straight line that passes through the origin, indicating that the reaction scheme and the calculation procedures of relative radical scavenging rate constants (kAOx/kST) using Eq. 1 are justified. Using similar procedures, ORAC-EPR values (kAOx/kST) relative to CYPMPO for seven lipophilic antioxidants were calculated and converted into trolox equivalent unit. Average ORAC-values after five repeated measurements are shown in Table 1 and Fig. 4 with standard deviation. Previous ORAC-FL data are also listed in Table 1 and Fig. 4.(10,30–35)

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.