Captopril as an antioxidant in lead-exposed Fischer 344 rats

Protective Effects of Green Tea Supplementation against Lead-Induced Neurotoxicity in Mice

The use of natural products as therapeutic agents is rapidly growing recently. In the current study, we investigated the protective effects of green tea supplementation on lead-induced toxicity in mice. Forty albino mice were divided into four groups as follows: A: control group; B: green tea receiving group; C: lead-intoxicated group; and D: lead-intoxicated group supplemented with green tea. At the end of the experiment, the animals were tested for neurobehavioral and biochemical alterations. Green tea was analyzed through Gas Chromatography–Mass Spectrometry (GC/MS) analysis. We found that supplementation with green tea ameliorated the lead-associated increase in body weight and blood glucose. Green tea supplementation also changed the blood picture that was affected due to lead toxicity and ameliorated lead-induced dyslipidemia. The group of mice that were supplemented with green tea has shown positive alterations in locomotory, anxiety, memory, and learning behaviors. The GC/MS analysis revealed many active ingredients among which the two most abundant were caffeine and 1,2-benzenedicarboxylic acid, mono(2-ethylhexyl) ester. We concluded that green tea supplementation has several positive effects on the lead-induced neurotoxicity in mice and that these effects may be attributed to its main two active ingredients.

Medicinal Thiols: Current Status and New Perspectives

The thiol (-SH) functional group is found in a number of drug compounds and confers a unique combination of useful properties. Thiol-containing drugs can reduce radicals and other toxic electrophiles, restore cellular thiol pools, and form stable complexes with heavy metals such as lead, arsenic, and copper. Thus, thiols can treat a variety of conditions by serving as radical scavengers, GSH prodrugs, or metal chelators. Many of the compounds discussed here have been in use for decades, yet continued exploration of their properties has yielded new understanding in recent years, which can be used to optimize their clinical application and provide insights into the development of new treatments. The purpose of this narrative review is to highlight the biochemistry of currently used thiol drugs within the context of developments reported in the last five years. More specifically, this review focuses on thiol drugs that represent the standard of care for their associated conditions, including N-acetylcysteine, 2,3-meso-dimercaptosuccinic acid, British anti-Lewisite, D-penicillamine, amifostine, and others. Reports of novel dosing regimens, delivery strategies, and clinical applications for these compounds were examined with an eye toward emerging approaches to address a wide range of medical conditions in the future.

Captopril Attenuates Diazinon-Induced Oxidative Stress: A Subchronic Study in Rats

BACKGROUND

Diazinon (DZN) is an organophosphate pesticide commonly used for pest control in agriculture. It may engender a variety of negative effects in non-target species, including humans and animals. The objective of the present study was to evaluate the ameliorative properties of captopril (CAP), as a thiol containing an angiotensin-converting enzyme inhibitor, against DZN-induced oxidative stress.

METHODS

Twenty-eight male Wistar rats were divided randomly into 4 groups. All the rats were treated orally via gavage once a day for 7 weeks: control (corn oil), CAP (10 mg/kg), DZN (10 mg/kg), and CAP+DZN combination (as mentioned above). Oxidative stress indices in blood serum, liver and kidney homogenates (malondialdehyde [MDA], total thiol groups, and total antioxidant capacity), and erythrocyte hemolysis (superoxide dismutase [SOD] and glutathione peroxidase) were evaluated. Statistical analysis was performed using GraphPad Prism software, version 6.0 (GraphPad, San Diego, CA, USA), by ANOVA, followed by the Tukey post hoc analysis.

RESULTS

The MDA content and SOD activity increased significantly in the DZN group compared with those in the control group. Treatment with CAP in the DZN-exposed group significantly decreased (P<0.05) the MDA concentration and the SOD activity. The total thiol groups were decreased in the DZN group and elevated again by CAP treatment.

CONCLUSION

The co-administration of CAP and DZN was able to attenuate lipid peroxidation and enzyme changes caused by DZN.

Captopril and Valsartan May Improve Cognitive Function Through Potentiation of the Brain Antioxidant Defense System and Attenuation of Oxidative/Nitrosative Damage in STZ-Induced Dementia in Rat

Purpose: Previous findings have shown the crucial roles of brain renin-angiotensin system (RAS) in pathogenesis of Alzheimer's disease (AD). Since RAS inhibitors may have beneficial effects on dementia and cognitive function in elderly people, the aim of present study was to examine the neuroprotective actions of captopril and valsartan on memory function and neuronal damage in experimental model of AD. Methods: Adult forty male Wistar rats (220-280g) were randomly divided into 5 groups; Control, Vehicle, Alzheimer and treatment groups. AD was induced by the injections of streptozotocin (3mg/kg, bilateral intracerebroventricular) at days 1&3. Treated rats received orally captopril (50mg/kg/day) and valsartan (30mg/kg/day). Memory function and histological assessments were done at termination of experiment. Finally, superoxide dismutase (SOD) and catalase (CAT) activities as well as malondialdehyde (MDA) and NOx contents were determined. Results: There was a significant increase in the mean value of latency in Alzheimer group (66%). Captopril and valsartan considerably decreased this value in both treatment groups (45% and 72%, respectively). In Alzheimer group the activities of brain's SOD and CAT reduced (40% and 47%, respectively) in accompany with an increase in MDA and NOx contents (49% and 50%, respectively). Captopril and valsartan significantly increased the activities of brain's SOD and CAT concomitant reduction in MDA and NOx contents. Also, histopathological damages noticeably decreased in both treatment groups. Conclusion: Our findings indicate that RAS inhibition by using captopril and valsartan potentiates the antioxidant defense system of brain and reduces oxidative/nitrosative stress in accompany with neuronal damage during AD.

Antioxidant effects of Etlingera elatior flower extract against lead acetate - induced perturbations in free radical scavenging enzymes and lipid peroxidation in rats

Background

Etlingera elatior or 'pink torch ginger' (Zingiberaceae) are widely cultivated in tropical countries and used as spices and food flavoring. The purpose of this study was to evaluate the antioxidant effects of Etlingera elatior against lead - induced changes in serum free radical scavenging enzymes and lipid hydroperoxides in rats.

Findings

Rats were exposed to lead acetate in drinking water (500 ppm) for 14 days alone or plus the ethanol extract of E. elatior (50, 100 and 200 mg/kg). Blood lead levels, lipid hydroperoxides, protein carbonyl contents and oxidative marker enzymes were estimated. Lead acetate in drinking water elicited a significant increase in lipid hydroperoxides (LPO) and protein-carbonyl-contents (PCC). There was a significant decrease in total antioxidants, superoxide dismutase, glutathione peroxidase and glutathione S-transferase levels with lead acetate treatment. Supplementation of E. elatior was associated with reduced serum LPO and PCC and a significant increase in total antioxidants and antioxidant enzyme levels.

Conclusions

The results suggest that flower extract of Etlingera elatior has powerful antioxidant effect against lead - induced oxidative stress and the extract may be useful therapeutic agent against lead toxicity. However, detailed evaluations are required to identify the active antioxidant compounds from this plant extract.

Sub-chronic lead exposure alters kidney proteome profiles

The current study examined the impact of sub-chronic lead (Pb)-exposure upon global protein profile in rodent kidney (blood Pb levels ~50 μg/dL; 5 weeks oral Pb-acetate exposure). Utilizing 2D SDS-PAGE for kidney protein separation, greater than 500 protein spots were analyzed by densitometry following background noise removal, spot alignment, and intensity filtering. Approximately 100 protein spots were identified by ESI-MS/MS with mitochondrial, chaperone, antioxidant, and Pb-binding proteins included. Forty-eight protein spots exhibited significant alterations in abundance (18 identified by ESI-MS/MS) including the increased protein abundance of ketohexokinase, enolase, protein disulfide-isomerase, lamda crystallin, lactamase, and glycerol-3-phosphate dehydrogenase. Decreased protein abundances were observed for α-2 microglobulin, glutamate cysteine ligase, prohibitin, homogentisate 1,2-dioxygenase, alpha-ETF, argininosuccinate synthetase and ATP synthase (H+ transporting). These data support the hypothesis that protein profiles in the kidney are altered following sub-chronic physiologically relevant Pb-exposure.

Casein fermentate of Lactobacillus animalis DPC6134 contains a range of novel propeptide angiotensin-converting enzyme inhibitors

This work evaluated the angiotensin-converting-enzyme (ACE)-inhibitory activities of a bovine sodium caseinate fermentate generated using the proteolytic capabilities of the porcine small intestinal isolate Lactobacillus animalis DPC6134 (NCIMB deposit 41355). The crude 10-kDa L. animalis DPC6134 fermentate exhibited ACE-inhibitory activity of 85.51% (+/-15%) and had a 50% inhibitory concentration (IC50) of 0.8 mg protein/ml compared to captopril, which had an IC50 value of 0.005 mg/ml. Fractionation of the crude L. animalis DPC6134 fermentate by membrane filtration and reversed-phase high-performance liquid chromatography (HPLC) generated three bioactive fractions from a total of 72 fractions. Fractions 10, 19, and 43 displayed ACE-inhibitory activity percentages of 67.53 (+/-15), 83.71 (+/-19), and 42.36 (+/-11), respectively, where ACE inhibition was determined with 80 microl of the fractions with protein concentrations of 0.5 mg/ml. HPLC and mass spectrometry analysis identified 25 distinct peptide sequences derived from alpha-, beta-, and kappa-caseins. In silico predictions, based on the C-terminal tetrapeptide sequences, suggested that peptide NIPPLTQTPVVVPPFIQ, corresponding to beta-casein f(73-89); peptide IGSENSEKTTMP, corresponding to alpha(s1)-casein f(201212); peptide SQSKVLPVPQ, corresponding to beta-casein f(166-175); peptide MPFPKYPVEP, corresponding to beta-casein f(124133); and peptide EPVLGPVRGPFP, corresponding to beta-casein f(210-221), contained ACE-inhibitory activities. These peptides were chosen for chemical synthesis to confirm the ACE-inhibitory activity of the fractions. Chemically synthesized peptides displayed IC50 values in the range of 92 microM to 790 microM. Additionally, a simulated gastrointestinal digestion confirmed that the ACE-inhibitory 10-kDa L. animalis DPC6134 fermentation was resistant to a cocktail of digestive enzymes found in the gastrointestinal tract.

ACE-inhibitory and radical-scavenging activity of peptides derived from beta-lactoglobulin f(19-25). Interactions with ascorbic acid

In this work, the angiotensin-converting enzyme (ACE)-inhibitory and radical-scavenging activities of the beta-lactoglobulin (beta-Lg)-derived peptides WY f(19-20), WYS f(19-21), WYSL f(19-22), WYSLA f(19-23), WYSLAM f(19-24), and WYSLAMA f(19-25) have been determined. The ACE-inhibitory activity (IC50) varied from 38.3 to 90.4 microM, with the exception of WYS (>500 microM). All beta-Lg-derived peptides also exhibited radical-scavenging activity (oxygen radical absorbance capacity (ORAC) values ranged from 4.45 to 7.67 micromol Trolox equivalents/micromol of peptide). The presence and position of amino acids Trp, Tyr, and Met were proposed to be responsible for the antioxidant activity. The equimolar amino acid mixtures of all the peptides showed ORAC values lower than those of the corresponding peptides, indicating that the peptidic bond or the structural conformation had a positive influence on this activity. Finally, positive antioxidant effects of WYS, WYSL, and WYLA with ascorbic acid were observed, whereas WY and WYSLAM showed negative effects, both cases for different molar ratio mixtures. These results should be taken into account in the development of new food ingredients on the basis of peptides from beta-Lg.

Lead-induced increase in antioxidant enzymes and lipid peroxidation products in developing rat brain

Pregnant rats were treated with 0.4% lead acetate through drinking water from 6th day of gestation and this treatment was continued till 21 post natal days (PND). Four regions of the brain namely hippocampus, cerebellum, frontal cortex and brain stem were dissected at 10, 20, 30 and 40 PND for estimation of lipid peroxidation products (LPP), catalase (CAT) and superoxide dismutase (SOD). The results indicate that there was a significant (P < 0.05) increase of LPP in exposed rats than their corresponding control at 10, 20 and 30 PND both in hippocampus and cerebellum. At PND 40, the LPP of control and exposed were found to be almost same in both the tissues indicating recovery from lead toxicity. CAT activity was significantly (P < 0.05) high in hippocampus of exposed rats up to PND 30 but up to PND 20 in cerebellum and frontal cortex. However, in brain stem, a significant (P < 0.05) increase in CAT activity was observed only at PND 10. A significant (P < 0.05) increase in SOD activity was observed up to PND 30 both in hippocampus and cerebellum on lead exposure. Frontal cortex exhibited a similar significant (P < 0.05) increase of SOD activity up to PND 20 and for brain stem up to PND 10. There was no significant change in the activity of antioxidant enzymes (CAT and SOD) and LPP in all the four brain tissues of control and exposed rats at PND 40 indicating recovery from lead-induced oxidative stress.

Lipids, lipid peroxidation and 7-ketocholesterol in workers exposed to lead

The study population included healthy men and hypertensive employees of zinc and lead steelworks in the south of Poland. Workers exposed to lead (n=137) were divided into two groups: the first included employees with low exposure to lead (LL) with mean blood lead (PbB) 25-40 microg/dL and the second one with PbB over 40 microg/dL (HL group). The administration workers (n=35) were the control group. Evaluation of lipids and oxidative changes of cholesterol and lipids were estimated in blood samples. No significant changes in concentration of 7-ketocholesterol and blood lipids (cholesterol, HDL, LDL, triglycerides) were found. Lipid peroxidation (LP) was significantly higher in both exposed groups in plasma and in the HL group in erythrocytes when compared with control. There can be two independent sources of LP increase: the first is connected with the direct effect of lead's ions on erythrocytes, the second is the prooxidative effect of delta-aminolevulinic acid. Hypertension in the HL group when compared with people with PbB below 40 microg/dL (OR 4.4, 95%CI 1.4-14.5) was found more often. LP significantly increased by about 71% and concentration of 7-ketocholesterol by about 122% in hypertensives when compared with normotensives in the HL group.

Combined efficacies of lipoic acid and 2,3-dimercaptosuccinic acid against lead-induced lipid peroxidation in rat liver

Oxidative stress with subsequent lipid peroxidation has been postulated as one mechanism for lead toxicity. Hence in assessing the protective effects of lipoic acid (LA) and meso 2,3-dimercaptosuccinic acid (DMSA) on lead toxicity, they were tested either separately or in combination for their effects on selected indices of hepatic oxidative stress. Elevated levels of lipid peroxides were accompanied by altered antioxidant defense systems. Lead acetate (Pb - 0.2%) was administered in drinking water for five weeks to induce toxicity. LA (25 mg kg(-1) body wt. day(-1) i.p) and DMSA (20 mg kg(-1) body wt. day(-1) i.p) were administered individually and also in combination during the sixth week. Lead damage to the liver was evident in the decreases in hepatic enzymes alanine transaminase (-38%), aspartate transaminase (-42%) and alkaline phosphatase (-43%); increases in lipid peroxidation (+38%); decreases in the antioxidant enzymes catalase (-45%), superoxide dismutase (-40%), glutathione peroxidase (-46%) and decreases in glutathione (-43%) and decreases in glutathione metabolizing enzymes, glutathione reductase (-59%), glucose-6-phosphate dehydrogenase (-27%) and glutathione-S-transferase (-42%). In combination LA and DMSA completely ameliorated the lead induced oxidative damage. Either compound alone was however only partially protective against lead damage.