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Abstract The present study was carried out to throw some light on the compounds understudy as a source of antioxidant agents against the free radicals originating from the environmental pollutions and their prophylactic role against oxidative stress. A survey of 38substances namely synthetic and natural compounds used in pharmaceutical preparations and as a food was carried out. This part, however, is devoted to study the antioxidant activity and scavenging capacity of these substances to choose the best one for both types by using different model systems. 1-FREE RADICAL SCAVENGING ACTIVITY Free radical scavenging activity of some acid compounds on DPPH radical The obtained data proved that all compounds have free radical scavenging activity against DPPH radical and this effect is dosedependent. Ascorbic acid has the highest free radical scavenging activity on DPPH radical. Free radical scavenging activity of some flavonoids on DPPH radical All compounds dose-dependently scavenged DPPH free radical. Free radical scavenging of four compounds at concentration160 μg/ml were ranked in the following order; catechin>qurecetin>rutin>silymarin. These results suggest the potential activity of catechin, quercetin, rutin and silymarin to prevent oxidative damage from free radical mediated oxidation. Free radical scavenging activity of some amines on DPPH radical The concentrations of the samples could not completely remove DPPH radical from the medium. The highest inhibition value (20.65+0.28%) was obtained for ρ-phenylinedimine at 160 μg/ml μg/ml concentrations. On the other hand ρ-nitro aniline had the lowest inhibition values by 12.29+0.42% at 160 μg/ml. Free radical scavenging activity of some phenols on DPPH radical The entire test compounds dose-dependently scavenged DPPH free radical. Among these compounds under investigation, catechol had the highest hydrogen-donating capacity against DPPH radical by 22.31%, whereas, resorcinol had the lowest free radical scavenging activity against DPPH radical by 11.05% at 160 μg/ml. In conclusion, it has been showed that catechin exerted the highest free radical scavenging activity on DPPH radical. 2-DNA DAMAGE SYSTEM AND-DEOXYRIBOSE SUGAR DEGRADA- TION SYSTEM 2.1-DNA DAMAGE SYSTEM Effect of some acids on free radical mediated DNA-damage All acids under investigation scavenged free radicals mediated DNA-damage in dose-dependent manner. Ascorbic acid and gallic acid had the highest scavenging effect against hydroxyl radical-induced DNA damage by 95.98 and 95.5% at 160 μg/ml, respectively. Effect of some flavonoids on free mediated DNA-damage All flavonoids under investigation dose-dependently scavenged hydroxyl radical-induced DNA damage at concentration of 160 μg/ml. All samples showed more than 50% scavenging effect on hydroxyl radical. Catechin at concentration of 160 μg/ml has the highest scavenging effect (97.5%) against hydroxyl radical, whereas, silymarin has the lowest effect by 77.33% at160 μg/ml. The scavenging effect of samples were recorded and found to be in the following order; catechin>querectin>rutin>silymarin. Effect of some amines on free radical mediated DNA-damage All amines under investigation exerted hydroxyl radical scavenging effect at concentration-dependent fashion. Among these amines under investigation, ρ-phenylenediamine had the highest inhibitory effect on hydroxyl radical by 19.50% at 160 μg/ml. On the other hand, ρ-nitro aniline had the lowest inhibitory effect on hydroxyl radical by 12.61% at160 μg/ml, respectively. Effect of some phenols on free radical mediated DNA-damage The highest scavenging activity (22.17%) was obtained for catechol at 160 μg/ml concentration, whereas resorcinol had the lowest scavenging values by 11.71% at 160 μg/ml. 2.1. 5-Effect of ρ-hydroxybenzaldehyde, tocophereol, riboflavin, selenium dioxide, biotin, ρ-hydroxycoumarin and coumarin on free radical mediated DNA-damage Samples were capable of scavenging hydroxyl radical in concentration-dependent manner. The highest scavenging effect value (73.9%) was obtained for tocopherol acetate, whereas the lowest value (9.2%) was for 4-hydroxybenzaldehyde at 160 μg/ml. It can be extracted from that catechin (97.5%) had the highest scavenging value on hydroxyl radical mediated DNA-damage. 2.2-DEOXYRIBOSE SUGAR DEGRADATION SYSTEM Inhibitory effect of some acids against hydroxyl radical mediated deoxyribose degradation All acids dose-dependently inhibited deoxyribose degradation by scavenge of hydroxyl radical. Gallic acid had the highest inhibitory effect (94.3%) at the concentration of 160μg/ml. In addition, ascorbic acid and Caffeic acid exerted 88.5 and 91.1% on hydroxyl radical. Inhibitory effect of some flavonoids against hydroxyl radical mediated deoxyribose degradation Catechin had the highest inhibitory effect (95.2%) against hydroxyl radical at 160 μg/ml concentration. All flavonoids under investigation showed more than 50% inhibitory effect on deoxyribosedegradation. Inhibitory effect of some amines against hydroxyl radical medical deoxyribose degradation All amines under investigation had inhibitory effect on hydroxyl radical mediated deoxyribose degradation and this effect was in a dosedependent manner. Ρ-Phenylenediamine had the highest value (18.89%), whereas p-nitraniline had the lowest one (9.18%). Inhibitory effect of some phenols against hydroxyl radical mediated deoxyribose degradation All samples were capable of scavenging hydroxyl radical in a dose-dependent manner. Catechol showed the highest inhibitory effect by23.25% at 160 μg/ml on hydroxyl radical mediated deoxyribose degradation. 2.2.5-Inhibitory effect of ρ-hydroxybenzaldehyde, tocophereol, riboflavin, selenium dioxide, biotin, ρ-hydroxycoumarin and coumarin against hydroxyl radical deoxyribose degradation Tocopherol-acetate had the highest inhibitory effect on hydroxyl radical by 59.3%, whereas 4-hydroxybenzaldehyde had the lowest value 10.8% at 160 μg/ml. In conclusion, catechin and quercetin had the highest inhibitory value at 160 μg/ml. 3-Ferrous/Ascorbate model system which produced hydroxyl radical and induced lipid peroxidation in liver mitochondria 3.1-Liver mitochondria Effect of some acids on ferrous/ascorbate system induced lipid peroxidation in rat liver mitochondria As shown, ascorbic acid had the highest inhibition effect against hydroxyl radical by 55.0, 82.8, 89.1 and 93.6% at 20, 40, 80, and 160 μg/ml, respectively. On the other hand salicylic acid had the lowest effect against hydroxyl radical by 9.1, 15.6, 18.2, 28.3 at 20, 40, 80, 160 μg/ml, respectively. Effect of some flavonoids on ferrous/ascorbate system induced lipid peroxidation in rat liver mitochondria There was a direct increase in the inhibitory effect of compound under investigation with the increase in the concentration of these compounds. The most potent effect was for the high concentration of qurecetin and catechin by 96.3% and 96.15% at 160 μg/ml, while the lowest inhibitory effect was for silymarin by 86.9 % at 160 μg/ml compared with control. Effect of some amines on ferrous/ascorbate system induced lipid peroxidation in rat liver mitochondria It has shown that ρ-phenylinediamine and o-phenylenediamine had the highest inhibitory effect against ferrous/ascorbate mode system by 26.57% and 25.41%, respectively at 160μg/ml in computation with control. Effect of some phenols on ferrous/ascorbate model system induced lipid peroxidation in mitochondria. It has been showed that the inhibition % was increased by increasing the concentration. The results showed that catechol exerted the highest inhibitory effect against lipid peroxidation by 26.5% at 160μg/ml. 90 3.1.5-Effect of ρ-hydroxybenzaldehyde, tocopherol, riboflavin, selenium dioxide biotin, ρ-hydroxycoumarin and coumarin on ferrous/ascorbate system induced lipid peroxidation in rat liver mitochondria The inhibitory effect was increased by increasing the concentration. It has shown that tocopherol acetate by four concentrations had the highest inhibition effect against lipid peroxidation by 89.3% at 160 μg/ml. However, ρ-hydroxybenzaldehyde exerted the lowest effect against lipid peroxidation by 15.3% at 160 μg/ml. In conclusion, it has been shown that quercetin, catechin and rutin exerted the highest inhibition effect at 160 μg/ml against lipid peroxidation in mitochondria induced by ferrous/ascorbate model system. 3.2-LIVER LYSOSOMES Effect of some acids on ferrous/ascorbate system induced lipid peroxidation in lysosomes. The data revealed that, the four concentrations of ascorbic acid and gallic acid exerted the highest inhibition effect against lipid peroxidation in lysosomes by 54.4, 82.7, 89.2, 92.9 % and 57.3, 78.3, 89.6, 92.2% at 20, 40, 80, 160 μg/ml, respectively. However, salicylic acid had the lowest inhibition effect by 8.9, 14.6, 19.8 and 27.3 % at 20, 40, 80, 160 μg/ml, respectively. Effect of some flavonoids on ferrous/ascorbate system induced lipid peroxidation in lysosomes. The results showed the comparative effects of four compounds by four concentrations on lipid peroxidation in lysosomes. The tested concentrations of qurcetein and rutin had the highest inhibitory effect by 96.9% and 96.6% at 160 μg/ml. 91 Effect of some amines on ferrous/ ascorbate system induced lipid peroxidation in lysosomes. All compounds increase the inhibition % by increasing the concentration. Also, ρ-phenylinediamine had the highest inhibition effect by 22.63%, at 160 μg/ml. In addition, o-phenylinediamine had highly inhibition % by 21.69%, at 160 μg/ml against lipid peroxidation. However, ρ-nitro aniline had the lowest inhibition effect by 15.82% at 160 μg //ml. Effect of some phenols on ferrous/ascorbate system induced lipid peroxidation in lysosomes. The inhibitory effect of caetchol exerted high increase by 6.05, 10.32, 16.30 and 24.99% at 20, 40, 80, 160 μg/ml, respectively. However, resorcinol had the lowest inhibition effect against lipid peroxidation by 6.05, 10.32, 11.30 and 13.99% at 20, 40, 80, 160 μg/ml, respectively. Effect of ρ-hydroxybenzaldehyde, tocopherol, riboflavin, selenium dioxide, biotin, ρ-hydroxycoumarin and coumarin on ferrous/ascorbate system induced lipid peroxidation in rat liver lysosomes. It has been showed that tocopherol-acetate exerted the highest inhibition effect by 88.6% at 160 μg/ml against lipid peroxidation in lysosomes, whereas ρ-hydroxybenzaldehyde showed the lowest inhibition effect against lipid peroxidation in lysosomes. In conclusion qurecetin, catechin and rutin had the highest inhibitory effect against LPO in lysosomes induced by ferrous/ascorbate mode system. 92 3.3-LIVER MICROSOMES Effect of some acids on ferrous/ascorbate system induced lipid peroxidation in rat liver microsomes. . Gallic acid exerted the highest inhibitory effect on lipidperoxidation in microsomes by 93.3% at 160 μg/ml, whereas, the high dose of ρ-amino benzoic acid had the lowest inhibitory effect on lipidperoxidation in microsomes by 32.2% at 160 μg/ml. Effect of some flavonoids on ferrous/ascorbate system induced lipid peroxidation in rat liver microsomes The results exerted that the inhibitory effect of flavonoids was dose-dependent manner. A high dose of rutin and catechin had the highest inhibitory effect against microtonal lipid peroxidation by 96.7, 96.5% at 160 μg/ml. Effect of some amins on Fe2+/ascorbate system induced lipid peroxidation in rat liver microsomes It has shown that p- phenylinedinediamine and ophenylinedinediamine had the highest inhibition effect lipid peroxidation by 26.57% and25.41% respectively at 160 μg/ml. Effect of some phenols on ferrous/ascorbate system induced lipid peroxidation in rat liver microsomes. It has been showed that the high concentration of catechol exerted the highest inhibitory effect against lipid peroxidation in microsomes by 23.48% at 160 μg/ml. 3.3.5-Effect of ρ-hydroxybenzaldehyde, tocophereol, riboflavin, selenium dioxide, biotin, ρ-hydroxycoumarin and coumarin on ferrous/ascorbate system induced lipid peroxidation in rat liver microsomes. There is a dose-dependent manner in all compounds under investigation. The data concluded that tocopherol acetate had the highest 93 inhibitory effect on ferrous/ascorbate induced LPO in microsomes by 88.2% at 160 μg/ml, whereas ρ-hydroxybenzaldehyde had the lowest inhibitory effect on ferrous/ascorbate by 16.0 at 160 μg/ml. It could be concluded that rutin, catechin and qurectin had the highest inhibitory effect against microsomes lipid peroxidation-induced by ferrous/ascorbate model system. 4-Effect of ascorbic acid, quercetin, caffeic acid, catechin and rutin on cisplatin-induedlysosomal membrane damage Acid phosphatase (AP) The data showed the effects of ascorbic acid, quercetin, caffeic acid, catechin and rutinby four doses (60, 120, 240, and 480 μg/ml) on cisplatin-induced lysosomal membrane damage and acid phosphatase release. Also, it has been revealed that the inhibitory effects of these compounds were dose-dependent manner. N- acetyl-glucosaminidase The results showed that the high dose exerted a high inhibitory effect on cisplatin induced free radical and the low dose had a low in inhibitory effect on cisplatin. The high dose of catechin and caffeic acid exerted highly decrease in β-N- acetyl-glucosaminidase enzymatic activity. β-galactosidase The data revealed that, the enzymatic activity of β-galactosidase was decreased under the effect of five compounds by four concentrations. The results showed that the high concentration of quercetin, catechin and rutin ameliorated the harmful effect of cisplatin by 86.7%. In conclusion, it has been showed that catechin exerted the highest free radical scavenging activity on DPPH radical and on hydroxyl radical mediated DNA-damage. Also, catechin and qurecetin had the highest inhibitory value on hydroxyl radical mediated deoxyribose 94 degradation. Furthermore, Quercetin, catechin and rutin exerted the highest inhibition effect at 160 μg/ml against lipid peroxidation in mitochondria, microsomes and lysosomes induced by ferrous/ascorbate model system. Ascorbic acid, quercetin, caffeic acid, catechin and rutin by four concentrations appeared to protect the lysosomal membrane against cisplatin. The results of this study stated that the five compounds could be taken with cisplatin to reduce its nephrotoxicity |