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Potential Antioxidant Activity of New Tetracyclic and Pentacyclic Nonlinear Phenothiazine Derivatives.

Engwa GA, Ayuk EL, Igbojekwe BU, Unaegbu M - Biochem Res Int (2016)

Bottom Line: The synthesized phenothiazine derivatives exhibited reducing power potential to convert Fe(3+) to Fe(2+) and high ability to scavenge H2O2 free radical in vitro.The catalase activity significantly increased (p < 0.05) in groups 1 and 2 animals that received the phenothiazine derivatives compared to the controls (groups 3 and 4) suggesting the ability of the phenothiazine derivatives to scavenge H2O2 in vivo.The results suggest that phenothiazine derivatives, especially 6-chloro-11-azabenzo[a]phenothiazine-5-one, possess antioxidant activity though 6-[4-bromophenyl]-10-methyl-11-azabenzo[a]phenothiazine-5-one was slightly toxic.

View Article: PubMed Central - PubMed

Affiliation: Biochemistry, Chemical Sciences Department, Godfrey Okoye University, PMB 01014, Thinkers Corner, Enugu, Nigeria.

ABSTRACT
The global increase in oxidative stress related diseases such as cancer, cardiovascular, and inflammatory diseases caused by overwhelming level of free radicals in the body has encouraged the search for new antioxidant agents. Based on the ability of newly synthesized phenothiazine derivatives (6-chloro-11-azabenzo[a]phenothiazine-5-one and 6-[4-bromophenyl]-10-methyl-11-azabenzo[a]phenothiazine-5-one) to oxidize H2O2, a known free radical to sulfoxide, this study assessed the in vitro and in vivo antioxidant activity. The synthesized phenothiazine derivatives exhibited reducing power potential to convert Fe(3+) to Fe(2+) and high ability to scavenge H2O2 free radical in vitro. These activities were comparable to ascorbic acid, a standard antioxidant. The catalase activity significantly increased (p < 0.05) in groups 1 and 2 animals that received the phenothiazine derivatives compared to the controls (groups 3 and 4) suggesting the ability of the phenothiazine derivatives to scavenge H2O2 in vivo. The malondialdehyde level in groups 1 and 2 animals was lower than that in group 3 that received the reference compound (ascorbic acid) and group 4 that received the solvent suggesting the ability of the phenothiazine derivatives to prevent lipid membrane damage. AST and bilirubin levels were higher in group 2 animals which received 6-[4-bromophenyl]-10-methyl-11-azabenzo[a]phenothiazine-5-one compared to group 3, the positive control. The results suggest that phenothiazine derivatives, especially 6-chloro-11-azabenzo[a]phenothiazine-5-one, possess antioxidant activity though 6-[4-bromophenyl]-10-methyl-11-azabenzo[a]phenothiazine-5-one was slightly toxic. This activity may be due to the presence of electron donors such as sulfur as well as the richness of hydrogen in the additional benzene rings for substitution. Further study is needed to identify tolerable doses for possible therapeutic purposes.

No MeSH data available.


Related in: MedlinePlus

Reducing power activity of the phenothiazine derivatives compared to standard.
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fig3: Reducing power activity of the phenothiazine derivatives compared to standard.

Mentions: In this study, the in vivo and in vitro antioxidant potential of two newly synthesized phenothiazine derivatives was investigated. The reducing power of the phenothiazine derivatives was determined by measuring the transformation of Fe3+ to Fe2+. As shown in Figure 3, the phenothiazine derivatives exhibited redox potential to scavenge free radicals which were comparable to ascorbic acid, a standard antioxidant. The reducing power of the 0.125 and 0.25 mg/mL concentrations of both compounds was similar to that of the positive control (ascorbic acid). However, at higher concentrations of 0.5 and 1 mg/mL, the reducing power of the two synthesized compounds was lower than that of ascorbic acid. The reducing power of 6-chloro-11-azabenzo[a]phenothiazine-5-one was slightly higher than that of 6-[4-bromophenyl]-10-methyl-11-azabenzo[a]phenothiazine-5-one at concentrations of 0.5 and 1.0 mg/mL. The ability of these compounds to reduce Fe3+ to Fe2+ may be due to the free electrons present in sulfur in the phenothiazine ring.


Potential Antioxidant Activity of New Tetracyclic and Pentacyclic Nonlinear Phenothiazine Derivatives.

Engwa GA, Ayuk EL, Igbojekwe BU, Unaegbu M - Biochem Res Int (2016)

Reducing power activity of the phenothiazine derivatives compared to standard.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4834405&req=5

fig3: Reducing power activity of the phenothiazine derivatives compared to standard.
Mentions: In this study, the in vivo and in vitro antioxidant potential of two newly synthesized phenothiazine derivatives was investigated. The reducing power of the phenothiazine derivatives was determined by measuring the transformation of Fe3+ to Fe2+. As shown in Figure 3, the phenothiazine derivatives exhibited redox potential to scavenge free radicals which were comparable to ascorbic acid, a standard antioxidant. The reducing power of the 0.125 and 0.25 mg/mL concentrations of both compounds was similar to that of the positive control (ascorbic acid). However, at higher concentrations of 0.5 and 1 mg/mL, the reducing power of the two synthesized compounds was lower than that of ascorbic acid. The reducing power of 6-chloro-11-azabenzo[a]phenothiazine-5-one was slightly higher than that of 6-[4-bromophenyl]-10-methyl-11-azabenzo[a]phenothiazine-5-one at concentrations of 0.5 and 1.0 mg/mL. The ability of these compounds to reduce Fe3+ to Fe2+ may be due to the free electrons present in sulfur in the phenothiazine ring.

Bottom Line: The synthesized phenothiazine derivatives exhibited reducing power potential to convert Fe(3+) to Fe(2+) and high ability to scavenge H2O2 free radical in vitro.The catalase activity significantly increased (p < 0.05) in groups 1 and 2 animals that received the phenothiazine derivatives compared to the controls (groups 3 and 4) suggesting the ability of the phenothiazine derivatives to scavenge H2O2 in vivo.The results suggest that phenothiazine derivatives, especially 6-chloro-11-azabenzo[a]phenothiazine-5-one, possess antioxidant activity though 6-[4-bromophenyl]-10-methyl-11-azabenzo[a]phenothiazine-5-one was slightly toxic.

View Article: PubMed Central - PubMed

Affiliation: Biochemistry, Chemical Sciences Department, Godfrey Okoye University, PMB 01014, Thinkers Corner, Enugu, Nigeria.

ABSTRACT
The global increase in oxidative stress related diseases such as cancer, cardiovascular, and inflammatory diseases caused by overwhelming level of free radicals in the body has encouraged the search for new antioxidant agents. Based on the ability of newly synthesized phenothiazine derivatives (6-chloro-11-azabenzo[a]phenothiazine-5-one and 6-[4-bromophenyl]-10-methyl-11-azabenzo[a]phenothiazine-5-one) to oxidize H2O2, a known free radical to sulfoxide, this study assessed the in vitro and in vivo antioxidant activity. The synthesized phenothiazine derivatives exhibited reducing power potential to convert Fe(3+) to Fe(2+) and high ability to scavenge H2O2 free radical in vitro. These activities were comparable to ascorbic acid, a standard antioxidant. The catalase activity significantly increased (p < 0.05) in groups 1 and 2 animals that received the phenothiazine derivatives compared to the controls (groups 3 and 4) suggesting the ability of the phenothiazine derivatives to scavenge H2O2 in vivo. The malondialdehyde level in groups 1 and 2 animals was lower than that in group 3 that received the reference compound (ascorbic acid) and group 4 that received the solvent suggesting the ability of the phenothiazine derivatives to prevent lipid membrane damage. AST and bilirubin levels were higher in group 2 animals which received 6-[4-bromophenyl]-10-methyl-11-azabenzo[a]phenothiazine-5-one compared to group 3, the positive control. The results suggest that phenothiazine derivatives, especially 6-chloro-11-azabenzo[a]phenothiazine-5-one, possess antioxidant activity though 6-[4-bromophenyl]-10-methyl-11-azabenzo[a]phenothiazine-5-one was slightly toxic. This activity may be due to the presence of electron donors such as sulfur as well as the richness of hydrogen in the additional benzene rings for substitution. Further study is needed to identify tolerable doses for possible therapeutic purposes.

No MeSH data available.


Related in: MedlinePlus