Human aldehyde dehydrogenase-catalyzed oxidation of ethylene glycol ether aldehydes

The Effect of Liver Hydrolysate on Chronic Ethanol-Induced Hepatic Injury in Normal Rats

The mechanism underlying the improvement in hepatic function by liver hydrolysate (LH) after ethanol-induced hepatic injury is unclear. Therefore, we investigated the effects of LH administration on chronic ethanol-induced hepatic injury in normal rats and the mechanism underlying the improvement of its symptoms by LH. LH attenuated liver damage and reduced oxidative stress after chronic ethanol-induced hepatic injury in normal rats. LH treatment reduced hepatic injury biomarkers of plasma aspartate aminotransferase (AST) and alanine aminotransferase (ALT). LH treatment also decreased levels of 8-hydroxy-deoxyguanosine (8-OHdG) as oxidative stress marker. LH may prove beneficial to prevent the liver damage of chronic ethanol, at least in part, by alleviating oxidative stress.

Silver(I) as a widely applicable, homogeneous catalyst for aerobic oxidation of aldehydes toward carboxylic acids in water-"silver mirror": From stoichiometric to catalytic

The first example of a homogeneous silver(I)-catalyzed aerobic oxidation of aldehydes in water is reported. More than 50 examples of different aliphatic and aromatic aldehydes, including natural products, were tested, and all of them successfully underwent aerobic oxidation to give the corresponding carboxylic acids in extremely high yields. The reaction conditions are very mild and greener, requiring only a very low silver(I) catalyst loading, using atmospheric oxygen as the oxidant and water as the solvent, and allowing gram-scale oxidation with only 2 mg of our catalyst. Chromatography is completely unnecessary for purification in most cases.

Testicular effect of a mixture of 2-methoxyethanol and 2-ethoxyethanol in rats

BACKGROUND

2-Methoxyethanol (ME) and 2-ethoxyethanol (EE) represent a large group of chemicals which are used separately or as mixtures. These compounds exert multidirectional toxic effects. The present studies aimed to demonstrate the effects of ME and EE alone and their mixture on the reproductive organs in the rats.

METHODS

Male Wistar rats were treated subcutaneously with ME and EE alone (1.25-5.0mM/kg/day) or with their mixture (1:1) for 4 weeks. After completion of the experiment, the testes, epididymides, and prostate were weighed. In post-mitochondrial supernatant of the testes, the level of total protein, non-protein and protein sulfhydryl groups, malondialdehyde, total antioxidant status, and glutathione peroxidase and glutathione reductase activities were determined.

RESULTS

Exposure to ME alone resulted in a dose-dependent decrease in the organ weights, the total protein, non-protein and protein sulfhydryl groups. EE alone led to less marked alterations. Co-exposure to ME and EE caused alterations similar as in the rats treated with ME alone.

CONCLUSIONS

Marked testicular atrophy, decrease in epididymis and prostate weights are predominant effects of the repeated exposure to relatively low doses of ME and EE. A decrease in the total protein level, and protein sulfhydryl groups may be responsible for testicular atrophy. A significant depletion of non-protein sulfhydryl groups and occasionally elevated glutathione peroxidase activity may indicate that ME and EE resulted in disturbances of pro-oxidant/antioxidant balance. The study suggests that testicular toxicity in male rats co-exposed to ME and EE is mainly caused by the former compound.

Schisandra chinensis prevents alcohol-induced fatty liver disease in rats

Schisandra chinensis (SC), a traditional herbal medicine, has been prescribed for patients suffering from various liver diseases, including hepatic cancer, hypercholesterolemia, and CCl₄-induced liver injury. We investigated whether SC extract has a protective effect on alcohol-induced fatty liver and studied its underlying mechanisms. Rats were fed with ethanol by intragastric administration every day for 5 weeks to induce alcoholic fatty liver. Ethanol treatment resulted in a significant increase in alanine aminotransferase, aspartate aminotransferase, and hepatic triglyceride (TG) levels and caused fatty degeneration of liver. Ethanol administration also elevated serum TG and total cholesterol (TC) and decreased high-density lipoprotein (HDL) cholesterol levels. However, after administration of ethanol plus SC extracts, the ethanol-induced elevation in liver TC and TG levels was reversed. Elevation in serum TG was not observed after treatment with SC. Moreover, compared with the ethanol-fed group, the rats administered ethanol along with SC extracts for 5 weeks showed attenuated fatty degeneration and an altered lipid profile with decreased serum TC and TG, and increased HDL cholesterol levels. Chronic ethanol consumption did not affect peroxisome proliferator-activated receptor γ (PPARγ) levels, but it decreased PPARα and phospho-AMP-activated protein kinase (AMPK) levels in the liver. However, SC prevented the ethanol-induced decrease in PPARα expression and induced a significant decrease in sterol regulatory element-binding protein-1 expression and increase in phospho-AMPK expression in rats with alcoholic fatty liver. SC administration resulted in a significant decrease in intracellular lipid accumulation in hepatocytes along with a decrease in serum TG levels, and it reversed fatty liver to normal conditions, as measured by biochemical and histological analyses. Our results indicate that the protective effect of SC is accompanied by a significant increase in phospho-AMPK and PPARα expression in hepatic tissue of alcoholic rats, thereby suggesting that SC has the ability to prevent ethanol-induced fatty liver, possibly through activation of AMPK and PPARα signaling.

Exposure of German residents to ethylene and propylene glycol ethers in general and after cleaning scenarios

Glycol ethers are a class of semi-volatile substances used as solvents in a variety of consumer products like cleaning agents, paints, cosmetics as well as chemical intermediates. We determined 11 metabolites of ethylene and propylene glycol ethers in 44 urine samples of German residents (background level study) and in urine samples of individuals after exposure to glycol ethers during cleaning activities (exposure study). In the study on the background exposure, methoxyacetic acid and phenoxyacetic acid (PhAA) could be detected in each urine sample with median (95th percentile) values of 0.11 mgL(-1) (0.30 mgL(-1)) and 0.80 mgL(-1) (23.6 mgL(-1)), respectively. The other metabolites were found in a limited number of samples or in none. In the exposure study, 5-8 rooms were cleaned with a cleaner containing ethylene glycol monobutyl ether (EGBE), propylene glycol monobutyl ether (PGBE), or ethylene glycol monopropyl ether (EGPE). During cleaning the mean levels in the indoor air were 7.5 mgm(-3) (EGBE), 3.0 mgm(-3) (PGBE), and 3.3 mgm(-3) (EGPE), respectively. The related metabolite levels analysed in the urine of the residents of the rooms at the day of cleaning were 2.4 mgL(-1) for butoxyacetic acid, 0.06 mgL(-1) for 2-butoxypropionic acid, and 2.3 mgL(-1) for n-propoxyacetic acid. Overall, our study indicates that the exposure of the population to glycol ethers is generally low, with the exception of PhAA. Moreover, the results of the cleaning scenarios demonstrate that the use of indoor cleaning agents containing glycol ethers can lead to a detectable internal exposure of residents.

Protective effects of polydatin from Polygonum cuspidatum against carbon tetrachloride-induced liver injury in mice

Polydatin is one of main compounds in Polygonum cuspidatum, a plant with both medicinal and nutritional value. The possible hepatoprotective effects of polydatin on acute liver injury mice induced by carbon tetrachloride (CCl₄) and the mechanisms involved were investigated. Intraperitoneal injection of CCl₄ (50 µl/kg) resulted in a significant increase in the levels of serum aspartate aminotransferase (AST), alanine aminotransferase (ALT) and hepatic malondialdehyde (MDA), also a marked enhancement in the expression of hepatic tumor necrosis factor-alpha (TNF-α), interleukin-1 beta (IL-1β), cyclooxygenase-2 (COX-2), inducible nitric oxide synthase (iNOS) and nuclearfactor-kappa B (NF-κB). On the other hand, decreased glutathione (GSH) content and activities of glutathione transferase (GST), superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) were observed following CCl₄ exposure. Nevertheless, all of these phenotypes were evidently reversed by preadministration of polydatin for 5 continuous days. The mRNA and protein expression levels of hepatic growth factor-beta1 (TGF-β₁) were enhanced further by polydatin. These results suggest that polydatin protects mice against CCl₄-induced liver injury through antioxidant stress and antiinflammatory effects. Polydatin may be an effective hepatoprotective agent and a promising candidate for the treatment of oxidative stress- and inflammation-related diseases.

Semen Hoveniae extract protects against acute alcohol-induced liver injury in mice

The protective effects of Semen Hoveniae extract (SHE) from Hovenia dulcis Thunb. (Rhamnaceae) on acute alcohol-induced liver injury were investigated in vivo using mice as test models. In the present study, SHE (150, 300, 600 mg/kg/day) was given to mice by intragastric administration for 4 days. Mice were gavaged with 60% ethanol 10 mL/kg after the last dose of extract. Six hours after alcohol administration, liver injury was evaluated by biochemical examination. Lipid peroxidation and the activity of antioxidants were measured by spectrophotometric methods. In mice, administration of SHE significantly decreased the activities of alanine aminotransferase (ALT) and aspartate transaminase (AST) in serum. Administration of SHE also protected against alcohol-induced alcohol dehydrogenase (ADH) elevation in mice. Concurrently, there was an augmentation in the activities of antioxidant enzymes such as superoxide dismutase (SOD), glutathione S-transferase (GST), and glutathione (GSH), and it also facilitated alcohol metabolism. Acute toxicity tests showed that a single dose of oral SHE up to 22 g/kg did not result in any death or toxic side effects in mice during 14 days' observation. These results demonstrate that SHE could protect against acute alcohol-induced liver injury without any toxic side effects. Therefore, Semen Hoveniae has potential for the development of a clinically useful agent which could protect the liver from alcohol-induced injury.