Limits...
Structure Effect on Antioxidant Activity of Catecholamines toward Singlet Oxygen and Other Reactive Oxygen Species in vitro.

Shimizu T, Nakanishi Y, Nakahara M, Wada N, Moro-Oka Y, Hirano T, Konishi T, Matsugo S - J Clin Biochem Nutr (2010)

Bottom Line: The results revealed that reactivity of catecholamines was markedly higher than that of sodium azide, and catechin as catechol reference.DMPO-OH signal of epinephrine was significantly small compared to other catecholamines, catechin, and 4-methylcatechol as a reference compound and was as small as that of tyrosine.These results indicated that epinephrine is the most potent singlet oxygen quencher than other catecholamines, and the secondary amino group in its alkyl side chain could play a role in unique singlet oxygen quenching property of epinephrine.

View Article: PubMed Central - PubMed

Affiliation: School of Natural System, College of Science and Engineering, Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan.

ABSTRACT
The reactivity of catecholamine neurotransmitters and the related metabolites were precisely investigated toward 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals and reactive oxygen species. Catecholamines reacted immediately with DPPH radicals, their reactivity being stronger than that of ascorbic acid as a reference. Superoxide scavenging activities of catecholamines determined by WST-1 and electron spin resonance (ESR) spin trapping methods were also high. Whereas tyrosine, the dopamine precursor showed no reactivity toward superoxide. The reactivity toward singlet oxygen was evaluated by observing specific photon emission from singlet oxygen. The results revealed that reactivity of catecholamines was markedly higher than that of sodium azide, and catechin as catechol reference. The reaction of catecholamines and singlet oxygen was further studied by ESR using 55-dimethyl-1-pyrroline N-oxide (DMPO) as a spin trapping reagent and rose bengal as photosensitizer. DMPO-OH signal of epinephrine was significantly small compared to other catecholamines, catechin, and 4-methylcatechol as a reference compound and was as small as that of tyrosine. The signal formation was totally dependent on singlet oxygen, and the presence of catechol compounds. These results indicated that epinephrine is the most potent singlet oxygen quencher than other catecholamines, and the secondary amino group in its alkyl side chain could play a role in unique singlet oxygen quenching property of epinephrine.

No MeSH data available.


Chemical structures of catecholamine neurotransmitters and catechin.
© Copyright Policy - open-access
Related In: Results  -  Collection


getmorefigures.php?uid=PMC2966927&req=5

Figure 1: Chemical structures of catecholamine neurotransmitters and catechin.

Mentions: The external administration of antioxidant is usually not effective to prevent brain oxidative stress because of the presence of the blood/brain/barrier (BBB) [6]. In addition, the activity of typical antioxidant enzymes such as superoxide dismutase (SOD) is lower in the brain than in other tissues such as liver [7]. Hence, we focused our attention on the reactivity of catecholamine neurotransmitters toward ROS and radical including 1,1-diphenyl-2-picrylhydrazyl (DPPH), superoxide, and singlet oxygen (Fig. 1). Superoxide is the most abundant ROS generated under physiological conditions and it is also generated by the auto-oxidation of dopamine [8]. Singlet oxygen, on the other hand, has been paid little attention on the oxidative stress compared with other ROS, although it causes damages DNA [9], PUFA [10], and amino acid [11] at the locus of generation. It is produced by a photosensitized reaction (photodynamic action) and also by enzyme-catalyzed reactions such as myeloperoxidase-hydrogen peroxide-chloride reaction in vivo system [12]. It also plays a role in cellular signaling and apoptosis [13–15]. Therefore, it is necessary to study the reactivity of singlet oxygen toward neurotransmitter molecules. Although several fragmented studies have been reported on the reactions of catecholamines toward ROS, we have re-evaluated the scavenging activity of a series of catecholamine neurotransmitters towards ROS, with special focus on their reactivity toward singlet oxygen.


Structure Effect on Antioxidant Activity of Catecholamines toward Singlet Oxygen and Other Reactive Oxygen Species in vitro.

Shimizu T, Nakanishi Y, Nakahara M, Wada N, Moro-Oka Y, Hirano T, Konishi T, Matsugo S - J Clin Biochem Nutr (2010)

Chemical structures of catecholamine neurotransmitters and catechin.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2966927&req=5

Figure 1: Chemical structures of catecholamine neurotransmitters and catechin.
Mentions: The external administration of antioxidant is usually not effective to prevent brain oxidative stress because of the presence of the blood/brain/barrier (BBB) [6]. In addition, the activity of typical antioxidant enzymes such as superoxide dismutase (SOD) is lower in the brain than in other tissues such as liver [7]. Hence, we focused our attention on the reactivity of catecholamine neurotransmitters toward ROS and radical including 1,1-diphenyl-2-picrylhydrazyl (DPPH), superoxide, and singlet oxygen (Fig. 1). Superoxide is the most abundant ROS generated under physiological conditions and it is also generated by the auto-oxidation of dopamine [8]. Singlet oxygen, on the other hand, has been paid little attention on the oxidative stress compared with other ROS, although it causes damages DNA [9], PUFA [10], and amino acid [11] at the locus of generation. It is produced by a photosensitized reaction (photodynamic action) and also by enzyme-catalyzed reactions such as myeloperoxidase-hydrogen peroxide-chloride reaction in vivo system [12]. It also plays a role in cellular signaling and apoptosis [13–15]. Therefore, it is necessary to study the reactivity of singlet oxygen toward neurotransmitter molecules. Although several fragmented studies have been reported on the reactions of catecholamines toward ROS, we have re-evaluated the scavenging activity of a series of catecholamine neurotransmitters towards ROS, with special focus on their reactivity toward singlet oxygen.

Bottom Line: The results revealed that reactivity of catecholamines was markedly higher than that of sodium azide, and catechin as catechol reference.DMPO-OH signal of epinephrine was significantly small compared to other catecholamines, catechin, and 4-methylcatechol as a reference compound and was as small as that of tyrosine.These results indicated that epinephrine is the most potent singlet oxygen quencher than other catecholamines, and the secondary amino group in its alkyl side chain could play a role in unique singlet oxygen quenching property of epinephrine.

View Article: PubMed Central - PubMed

Affiliation: School of Natural System, College of Science and Engineering, Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan.

ABSTRACT
The reactivity of catecholamine neurotransmitters and the related metabolites were precisely investigated toward 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals and reactive oxygen species. Catecholamines reacted immediately with DPPH radicals, their reactivity being stronger than that of ascorbic acid as a reference. Superoxide scavenging activities of catecholamines determined by WST-1 and electron spin resonance (ESR) spin trapping methods were also high. Whereas tyrosine, the dopamine precursor showed no reactivity toward superoxide. The reactivity toward singlet oxygen was evaluated by observing specific photon emission from singlet oxygen. The results revealed that reactivity of catecholamines was markedly higher than that of sodium azide, and catechin as catechol reference. The reaction of catecholamines and singlet oxygen was further studied by ESR using 55-dimethyl-1-pyrroline N-oxide (DMPO) as a spin trapping reagent and rose bengal as photosensitizer. DMPO-OH signal of epinephrine was significantly small compared to other catecholamines, catechin, and 4-methylcatechol as a reference compound and was as small as that of tyrosine. The signal formation was totally dependent on singlet oxygen, and the presence of catechol compounds. These results indicated that epinephrine is the most potent singlet oxygen quencher than other catecholamines, and the secondary amino group in its alkyl side chain could play a role in unique singlet oxygen quenching property of epinephrine.

No MeSH data available.