Benay Can Eke

Synthesis and antioxidant properties of some novel benzimidazole derivatives on lipid peroxidation in the rat liver

Some benzimidazole derivatives namely 1-[(substituted thiocarbamoylhydrazine carbonyl) methyl]-2-phenyl-1H-benzimidazoles (1a-13a),N-[(2-phenylbenzimidazol-1-yl methyl)-[1,3,4]-thiadiazole-2-ylj-substituted phenyl amines (1b-13b) and 5-(2-phenyl benzimidazol-1-yl-methyl)-4-substituted phenyl-4H-1,2,4-triazole-3-thiones (1c-13c) were synthesized, and theirin vitro effects on the rat liver microsomal NADPH-dependent lipid peroxidation (LP) levels were determined. The most active compound10a caused an 84% inhibition of LP at 10-3 M, which is better than that of butylated hydroxytoluene (BHT) (65%).

The Organochlorine Pesticide Residues and Antioxidant Enzyme Activities in Human Breast Tumors: Is There Any Association?

The levels of some organochlorine pesticides (OCP)s (hexachlorobenzene, HCB, α-hexachlorocyclohexane, α-HCH, β-HCH, γ-HCH, heptachlorepoxide, HE, bis (4-chlorophenyl)-1,1-dichloroethene, p.p′DDE, bis (4-chlorophenyl)-1,1,1-trichloroethane, p.p′ DDT and total DDT (Σ-DDT) and antioxidant enzyme activities namely Cu, Zn superoxide dismutase (SOD), catalase (CAT), selenium-dependent glutathione peroxidase (Se-GSH-Px), total glutathione peroxidase (T-GSH-Px), selenium independent glutathione peroxidase (GSH-Px II), glutathione reductase (GRd), level of reduced glutathione (GSH) and lipid peroxidation (LP), glutathione S-transferase (GST) activity toward several substrates including 1-chloro-2,4-dinitrobenzene (CDNB), 1,2-dichloro-4-nitrobenzene (DCNB), ethacrynic acid (EAA), 1,2-epoxy-3-(p-nitrophenoxy)-propane (ENPP) were measured in tumor and surrounding tumor free tissues of 24 female breast cancer patients and was evaluated whether there exist any association between the levels of OCPs and antioxidants. The mean levels of GSH, α-BHC, γ-BHC and HE, and activities of SOD, Se-GSH-Px, T-GSH-Px, GSH-Px II,GRd, GST CDNB, and GST DCNB were significantly higher in tumors than in controls. In tumors, significant correlations were noted between: SOD and γ-BHC; Se-GSH-Px and γ-BHC; T-GSH-Px and γ-BHC; GSH-Px II and α-BHC, γ-BHC; GSH and α-BHC, γ-BHC, HE; GRd and α-BHC; CDNB GST and α-BHC, γ-BHC. These results show that free-radical mediated oxidative stress is, at least partly, associated with some of these OCP residues in human breast tumors.

DIFFERENTIAL RESPONSES OF HEPATIC MONOOXYGENASES AND GLUTATHIONE S-TRANSFERASES OF MICE TO A COMBINATION OF CADMIUM AND NICKEL

The acute combined effects of cadmium (Cd) and nickel (Ni) on hepatic monooxygenase activities (ethylmorphine N-demethylase, EMND; aminopyrine N-demethylase, AMND; aniline 4-hydroxylase, AH), cytochrome P-450, cytochrome b5, microsomal heme and reduced glutathione (GSH) levels and glutathione S-transferase (GST) activities toward several substrates (1-chloro-2,4-dinitrobenzene, CDNB; 1,2-dichloro-4-nitrobenzene, DCNB; ethacrynic acid, EAA; 1,2-epoxy-3-(p-nitrophenoxy)-propane, ENPP) were determined and compared with those of Cd or Ni alone in mice. Male adult mice (25-30 g) were administered either a single dose of Cd (3.58 mg CdCl2.H2O/kg, i.p.) 48 hr prior to killing or a single dose of Ni (59.5 mg NiCl2.H2O/kg, s.c.) 16 hr prior to killing. For the combined treatment, the animals received the single dose of Ni 32 hr after the single dose of Cd and were then killed 16 hr later. Cd treatment alone significantly decreased EMND, AMND, and AH activities and cytochrome P-450 and heme levels as compared with controls. Cytochrome b5 level was not altered by Cd treatment. Cd also inhibited GSH level and the GST activities toward CDNB, EAA and ENPP significantly. No significant change was observed in the GST activity for DCNB by Cd. Ni treatment alone, however, decreased the monooxygenase and GST activities studied, and cytochrome P-450, cytochrome b5, heme and GSH levels significantly. Combined treatment significantly depressed the monooxygenase activities and cytochromes and heme levels. GSH level was not significantly altered.(ABSTRACT TRUNCATED AT 250 WORDS)

The responses of hepatic monooxygenases of guinea pig to cadmium and nickel

When Cd (3.58 mg CdCl2·H2O/kg, ip) was administered to male guinea pigs 72 h prior to sacrifice, the metal significantly inhibited the aniline 4-hydroxylase (AH) (16%), ethylmorphoneN-demethylase (EMND) (26%), and aminopyrineN-demethylase (AMND) (18%) activities and cytochrome P-450 (12%) and cytochrome b5 (10%) levels. Cd did not alter the hepatic microsomal heme level. Cd, however, significantly increased the hepatic microsomalp-nitroanisoleO-demethylase (p-NAOD) (53%) activity. When Ni (59.5 mg NiCl2·6H2O/kg, sc) was administered to the guinea pigs 16 h prior to sacrifice, the metal significantly depressed AH (49%),p-NAOD (66%), EMND (47%), and AMND (37%) activities, and cytochrome P-450 (15%), cytochrome b5 (24%), and microsomal heme (28%) levels. For the combined treatment, animals received the single dose of Ni 56 h after the single dose of Cd and then were killed 16 h later. In these animals, significant inhibitions were noted in AH (51%), EMND (47%), and AMND (30%) activities, and cytochrome P-450 (15%), cytochrome b5 (26%), and microsomal heme (30%) compared to those of controls. In the case ofp-NAOD activity, the influence was in favor of Ni, i.e, the inhibition was about 61% by the combined treatment. These results reveal that:1.The response of all substrates of hepatic monooxygenases to Cd are not the same, possibly indicating differential regulation of cytochrome P-450 isozymes by Cd;2.The inhibitory effect of Ni on hepatic monooxygenases is more profound than that of Cd; and3.The combination of Cd and Ni does not have a synergistic effect of hepatic monooxygenases of the guinea pig.

Xenobiotic metabolizing and antioxidant enzymes in normal and neoplastic human breast tissue.

SummaryAn investigation was made of ethoxyresorufinO-deethylase (EROD) activity, a cytochrome P450 (CYP) dependent enzyme mainly catalyzed by CYP1A1, glutathioneS-transferase (GST) activity toward the substrates 1-chloro-2,4-dinitrobenzene (CDNB) and ethacrynic acid (EAA), reduced glutathione (GSH) levels, and antioxidant enzyme (AOE) activity namely catalase (CAT) and selenium-dependent glutathione peroxidase (Se-GPx) in tumor and surrounding tumor-free (normal) tissues in female breast cancer patients. Wide interindividual variations were found in the enzyme activities in both tumor and normal breast tissues. No significant differences were noted between mean EROD and CAT activities in tumor and normal breast tissues. The mean activities of CDNB GST, EAA GST and Se-GPx and GSH levels in tumor tissue were significantly higher than those in normal breast tissue. These results show that CYP, GST and AOE behave differentially in breast tumors.

Age dependent differential effects of cigarette smoke on hepatic and pulmonary xenobiotic metabolizing enzymes in rats

Abstract The effects of cigarette smoke (CS) on hepatic and pulmonary monooxygenase (MO) activities (aniline␣4-hydroxylase, AH; aminopyrine N-demethylase, AMND; 7-ethoxyresorufin O-deethylase, EROD; p-nitroanisole O-demethylase, p-NAOD), lipid peroxidation (LP), and reduced glutathione (GSH) levels and glutathione S-transferase (GST) activities toward several substrates (1-chloro-2,4-dinitrobenzene, CDNB; 1,2-dichloro-4-nitrobenzene, DCNB; ethacrynic acid, EAA; 1,2-epoxy-3-( p-nitrophenoxy)-propane, ENPP) were determined in 20-, 90- and 360-day-old male rats. The animals were exposed to CS five times a day, with 1 h intervals, for 3 days in a chamber supplied alternatively with smoke and fresh air, and were killed 16 h after the last treatments. The hepatic AH activity increased significantly in 20-day-old rats and remained unaltered in older age groups. The hepatic AMND activity unaltered, significantly increased and decreased in 20-, 90- and 360-day-old rats, respectively. The pulmonary AH activity increased significantly in 20- and 90-day-old rats whereas no alteration was noted in 360-day-old rats. CS was ineffective on pulmonary AMND activity at all ages. CS increased hepatic and pulmonary EROD and p-NAOD activities significantly in all age groups compared to controls. In liver, LP level was significantly increased, decreased, and unaltered in 20-, 90- and 360-day-old rats, respectively. CS increased hepatic GSH level significantly in 90-day-old rats but was not effective in the other age groups. In lung, LP level was increased in 90- and 360-day-old rats and unaltered in 20-day-old rats. CS increased pulmonary GSH level significantly in 90-day-old rats and did not have any effect in the other age groups. The hepatic GST activities toward CDNB and DCNB decreased significantly in 360-day-old rats and were unaltered in the younger age groups. The hepatic GST activity toward EAA was unaltered, significantly increased and decreased in 20-, 90- and 360-day-old rats, respectively. The hepatic GST activity toward ENPP decreased significantly in 20- and 90-day-old rats but was unaltered in the oldest group of rats. In 20-day-old rats, the pulmonary GST activity toward ENPP increased significantly whereas the other GST activities did not alter. In 90-day-old rats, however, CS significantly decreased all the pulmonary GST activities studied. Unaltered DCNB GST, significant increase in EAA GST and decrease in CDNB and ENPP GST activities of lung were noted in 360-day-old rats. These results reveal that the regulation in rats of hepatic and pulmonary MO and GST activities are differentially influenced by CS as a function of age.

COMBINED EFFECTS OF ETHANOL AND CIGARETTE SMOKE ON HEPATIC AND PULMONARY XENOBIOTIC METABOLIZING ENZYMES IN RATS

The combined effects of ethanol (EtOH) and cigarette smoke (CS) on hepatic and pulmonary monooxygenase (MO) activities (aniline 4-hydroxylase (AH), aminopyrine N-demethylase (AMND), 7-ethoxyresorufin O-deethylase (EROD), p-nitroanisole O-demethylase (p-NAOD)), lipid peroxidation (LP) and reduced glutathione (GSH) levels and glutathione S-transferase (GST) activities toward several substrates (l-chloro-2,4-dinitrobenzene (CDNB), 1,2-dichloro-4-nitrobenzene (DCNB), ethacrynic acid (EAA), 1,2-epoxy-3-(p-nitrophenoxy)-propane (ENPP)) were determined and compared with those of EtOH or CS alone in rats. When the male adult rats (225-275 g) were treated with 10% EtOH (v/v) in their drinking for 21 days AH, AMND and EROD activities and LP and GSH levels increased significantly whereas GST activity for EAA decreased significantly in liver as compared to controls. EtOH did not change the hepatic p-NAOD and GST activities toward CDNB, DCNB and ENPP. In lung, EtOH increased GST activities toward CDNB and ENPP and LP level but decreased GST activity toward DCNB, significantly. No alterations were noted in pulmonary MO activities and GST activity toward EAA and GSH level by EtOH treatment. When the animals were exposed to CS five times a day, with 1 h intervals, for 3 days in a chamber where smoke and fresh air lead alternatively, AMND, EROD and p-NAOD activities, GST activity toward EAA and GSH level increased but LP level and GST activity for ENPP decreased significantly in liver. CS did not alter the hepatic AH and GST activities toward CDNB and DCNB. In lung, CS increased AH, EROD and p-NAOD activities and LP and GSH levels and decreased all the GST activities studied significantly. CS had no influence on pulmonary AMND activity. For the combined treatment, the animals were treated with 10% EtOH (v/v) in their drinking water for 21 days and during the last 3 days they were exposed to CS five times a day, with 1 h intervals, in a chamber where smoke and fresh air lead alternatively. In these animals, augmentation of elevations were noted in AH and p-NAOD activities and LP and GSH levels but not in EROD and AMND activities in liver. Combined treatment significantly decreased GST activity toward CDNB, ameliorated the alteration caused by either EtOH or CS treatment alone on GST activity toward EAA and potentiated the depression of GST activity toward ENPP to a greater degree. No change was observed in GST activity toward DCNB. In lung, combined treatment potentiated the elevations of AMND and p-NAOD activities and LP level and not those of AH and EROD activities. GST activities toward CDNB, DCNB and ENPP were highly elevated by the combined treatment. No changes were observed in pulmonary GSH level and GST activity for EAA by the combined treatment. These results reveal that the regulations of the hepatic and pulmonary MO and GST are differentially influenced by EtOH, CS and the combined treatment.

Effects of cigarette smoke with different tar contents on hepatic and pulmonary xenobiotic metabolizing enzymes in rats

The effects of smoke from cigarettes with two different tar contents (32 mg/cigarette, high tar, and 15 mg/cigarette, low tar) on hepatic and pulmonary monooxygenase (MO) activities (aniline 4-hydroxylase [AH]; aminopyrine N-demethylase [AMND]; 7-ethoxyresorufin O-deethylase [EROD]; p-nitroanisole O-demethylase [p-NAOD]), lipid peroxidation (LP) and reduced glutathione (GSH) levels and glutathione S-transferase (GST) activities toward several substrates (1-chloro-2,4-dinitrobenzene [CDNB]; 1,2-dichloro-4-nitrobenzene [DCNB]; ethacrynic acid [EAA]; 1,2-epoxy-3-(p-nitrophenoxy)-propane [ENPP]) were determined in adult male rats. Adult male rats were exposed to smoke of high-or low-tar cigarettes five times a day, with 1-hour intervals, for 3 days in a chamber where smoke and fresh air lead alternatively and were killed 16 hours after the last treatment. Smoke of both high-and low-tar cigarettes (SHTCC and SLTCC) significantly increased hepatic and pulmonary EROD and p-NAOD activities compared to controls. However, the increase noted by SHTCC on pulmonary EROD activity was higher than that of SLTCC. Hepatic AMND and pulmonary AH activities were significantly increased only by SHTCC. LP level was significantly decreased and increased by SHTCC in liver and lung, respectively, whereas it remained unaltered by SLTCC. Only SHTCC significantly increased GSH level in liver. In the lungs, both SHTCC and SLTCC significantly increased GSH level to the same extent. Hepatic GST activity toward EAA was significantly increased by SHTCC but was significantly decreased by SLTCC. ENPP GST activity was significantly decreased by SHTCC and SLTCC in the livers. In the lungs, all the GST activities examined were significantly depressed by SHTCC whereas only GST activity toward DCNB was reduced significantly by SLTCC. These results reveal that the hepatic and pulmonary MOs and GSTs are differentially influenced by SHTCC and SLTCC in rats.

Combined effects of cadmium and nickel on hepatic glutathione S-transferases in rats.

1. The acute combined effects of cadmium (Cd) and nickel (Ni) on rat hepatic glutathione S-transferase (GST) activities toward the substrates 1-chloro-2,4-dinitrobenzene (CDNB), 1,2-dichloro-4-nitrobenzene (DCNB) and ethacrynic acid (EAA) were determined and compared to those of Cd or Ni alone. 2. Male adult rats (225-275 g) were administered either a single dose of Cd (3.58 mg CdCl2.H2O/kg, i.p.) 72 hr prior to sacrifice or a single dose of Ni (59.5 mg NiCl2.6H2O/kg, s.c.) 16 hr prior to sacrifice. For the combined treatment, animals received the single dose of Ni 56 hr after the single dose of Cd and they were killed 16 hr later. 3. Cd treatment alone did not produce any changes in the hepatic GST activities toward the substrates studied. 4. Ni treatment alone, however, significantly increased hepatic GST activity toward EAA whereas it was ineffective on GST activities for CDNB and DCNB. 5. Combined treatment of metals did not alter hepatic GST activities toward the substrates CDNB and DCNB. Hepatic GST activity for EAA, however, was significantly increased by the combined treatment. Nevertheless, the combined treatment did not augment the increase in GST activity for EAA noted by Ni treatment alone.

Gender dependent effects of cigarette smoke on hepatic and pulmonary xenobiotic metabolizing enzymes in rats

The adult male and female rats were exposed to cigarette smoke (CS) 5 times a day, with 1 h intervals, for 3 days in a chamber where smoke and fresh air lead alternatively and were killed 16 h after the last treatments and hepatic and pulmonary monooxygenase (MO) activities (aniline-4-hydroxylase, AH; aminopyrine-N-demethylase, AMND; 7-ethoxyresorufin-O-deethylase, EROD; p-nitroanisole-O-demethylase, p-NAOD), lipid peroxidation (LP) and reduced glutathione (GSH) levels and glutathione-S-transferases (GSTs) activities toward several substrates (1-chloro-2,4-dinitrobenzene, CDNB; 1,2-dichloro-4-nitrobenzene, DCNB; ethacrynic acid, EAA; 1,2-epoxy-3-(p-nitrophenoxy)-propane, ENPP) were determined. CS significantly increased hepatic AMND, EROD and p-NAOD activities whereas it unaltered AH activity in both genders as compared with controls. In the lung, EROD and p-NAOD activities were also significantly increased by CS in both genders. Pulmonary AH activity, however, significantly increased in males but remained unchanged in females. Pulmonary AMND activity significantly increased in females but remained unaltered in males. A significant decrease was noted in the LP level of males, while that of females was unaltered by CS in the liver. Pulmonary GSH and LP, and hepatic GSH levels were significantly increased by CS in both genders. In males, GST activities toward CDNB and DCNB did not alter, whereas GST activities toward EAA and ENPP significantly increased and decreased, respectively, in the liver. In females, CS significantly increased hepatic GST activity toward DCNB but it was ineffective on the other hepatic GST activities. All pulmonary GST activities of males were significantly depressed by CS. In females, however, CS significantly increased pulmonary GST activities toward CDNB and DCNB but was ineffective on GST activities toward EAA and ENPP. These results suggest that gender related differences exist in the modulations of hepatic GST, and pulmonary MO and GST activities but not in those of hepatic MO activities, by CS in rats.