Protective effects of butylated hydroxytoluene on the initiation of N-nitrosodiethylamine-induced hepatocellular carcinoma in albino rats.

Diethylnitrosamine (DEN), a hepatocarcinogen, is found in a variety of smoked and fried foods and was reported to be hepatotoxic in mice. Butylated hydroxytoluene (BHT) is a potent antioxidant used in cosmetic formulations and as a food additive and preservative. As a result, BHT was studied as a potential inhibitor in the early stages of diethylnitrosamine (DEN)-induced HCC. Male Wistar albino rats (n = 24) were equally subdivided. Group 1 was the negative control; Group 2 and 3 administered BHT and DEN, respectively; Group 4 received BHT followed by DEN. Blood samples and rat livers were taken for biochemical and histological investigation. Hepatotoxicity was assessed by increased liver enzymes and HCC indicators, along with reduced antioxidant and pro-apoptotic factors. AFP, AFPL3, GPC3, GSH, SOD, MDA, CASP3 and BAX expression increased significantly after DEN treatment. DEN also reduced GPx, CAT, and CYP2E1 activity, and BCl-2 expression. Moreover, in the hepatic parenchyma, the DEN caused histological alterations. Pretreatment with BHT enhanced antioxidant status while preventing histopathological and most biochemical alterations. BHT pretreatment suppresses DEN-initiated HCC by decreasing oxidative stress, triggering intrinsic mitotic apoptosis, and preventing histopathological changes in liver tissue.

The protective effect of butylated hydroxytoluene and 3-hydroxytyrosol on food allergy in mice.

OBJECTIVE: To test the effect of two dietary antioxidants: butylated hydroxytoluene (BHT) and 3-hydroxytyrosol (3-HT) in experimental food allergy. METHODS: BALB/c mice maintained on control diet or diet with BHT or 3-HT were sensitized with ovalbumin (OVA) or saline through transdermal exposure. Plasma OVA-specific IgE (OVA-IgE) and IgG1 (OVA-IgG1) antibody levels were determined using ELISA. Sensitized mice were challenged by oral gavage with OVA. Rectal temperature (RT) was measured before and after challenge. Mast cell degranulation was quantified by measuring the plasma levels of mouse mucosal mast cell protease-1 (mMCP-1). Flow cytometry was carried out to evaluate the percentage Th2 cells from the spleen. RESULTS: Mice on either a 3-HT or BHT diet showed a significantly decreased IgE response to OVA sensitization and less severe anaphylaxis, as evidenced by a diminished drop in body temperature, attenuated clinical signs, a more rapid recovery and decreased mast cell degranulation (as determined by lower plasma mMCP-1 levels). CONCLUSION: The present study indicates two dietary antioxidants: BHT and 3-HT may be protective against experimental food allergy. These results suggest 3-HT and BHT could potentially be useful for prevention of food allergy.

New Multifunctional Agents Based on Conjugates of 4-Amino-2,3-polymethylenequinoline and Butylated Hydroxytoluene for Alzheimer's Disease Treatment.

New hybrids of 4-amino-2,3-polymethylenequinoline with different sizes of the aliphatic ring linked to butylated hydroxytoluene (BHT) by enaminoalkyl (7) or aminoalkyl (8) spacers were synthesized as potential multifunctional agents for Alzheimer's disease (AD) treatment. All compounds were potent inhibitors of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) with selectivity toward BChE. Lead compound 8c, 2,6-di-tert-butyl-4-{[2-(7,8,9,10- tetrahydro-6H-cyclohepta[b]quinolin-11-ylamino)-ethylimino]-methyl}-phenol exhibited an IC50(AChE) = 1.90 ± 0.16 µM, IC50(BChE) = 0.084 ± 0.008 µM, and 13.6 ± 1.2% propidium displacement at 20 µM. Compounds possessed low activity against carboxylesterase, indicating likely absence of clinically unwanted drug-drug interactions. Kinetics were consistent with mixed-type reversible inhibition of both cholinesterases. Docking indicated binding to catalytic and peripheral AChE sites; peripheral site binding along with propidium displacement suggest the potential of the hybrids to block AChE-induced ß-amyloid aggregation, a disease-modifying effect. Compounds demonstrated high antioxidant activity in ABTS and FRAP assays as well as inhibition of luminol chemiluminescence and lipid peroxidation in mouse brain homogenates. Conjugates 8 with amine-containing spacers were better antioxidants than those with enamine spacers 7. Computational ADMET profiles for all compounds predicted good blood-brain barrier distribution (permeability), good intestinal absorption, and medium cardiac toxicity risk. Overall, based on their favorable pharmacological and ADMET profiles, conjugates 8 appear promising as candidates for AD therapeutics.

Protective effect of butylated hydroxytoluene on sperm function in human spermatozoa cryopreserved by vitrification technique.

Butylhydroxytoluene (BHT), a synthetic analogue of vitamin E, shows antioxidant and antiviral properties and has been successfully used for mammalian sperm cryopreservation. In this study, BHT was included in a vitrification solution to determine its cryoprotective effect on human spermatozoa. Spermatozoa were selected by swim-up and vitrified in close sealed straw using either a combination of human tubal fluid (HTF), sucrose and BHT 1 mm (VMBHT), or only HTF and sucrose (VM). The optimal concentration of BHT was determined by the observation of preserved progressive sperm motility (PSM) after warming and detection of plasma membrane (PMI), membrane mitochondrial potential (ΔΨm) and DNA integrity. The presence of reactive oxygen species (ROS) was also detected. The PSM was significantly higher in the VMBHT group (80.86 ± 5.41%) compared with the VM group (68.9 ± 3.67%) (P < 0.05). Butylhydroxytoluene significantly preserved DNA integrity (4.0 ± 0.1% versus 6.1 ± 1.6%; P < 0.05) and reduced ROS production (5.5 ± 2.2 versus 8.6 ± 1.8%; P < 0.05). Plasma membrane and ΔΨm showed no statistical differences. One millimolar BHT effectively maintained cell function and due to its antioxidant and antiviral properties could be used in semen cryopreservation of patients with viral infections transmitted by seminal plasma.

Butylated hydroxytoluene chemoprevention of aflatoxicosis - effects on aflatoxin B(1) bioavailability, hepatic DNA adduct formation, and biliary excretion.

The extreme sensitivity of turkeys to aflatoxin B(1) (AFB(1)) is associated with efficient hepatic cytochrome P-450 (P450)-mediated bioactivation, and deficient glutathione S-transferase (GST) mediated detoxification. Butylated hydroxytoluene (BHT) protects against AFB(1) toxicity in turkeys through mechanisms that include competitive inhibition of P450-mediated AFB(1) bioactivation. To test whether dietary BHT alters hepatic AFB(1)-DNA adduct formation, excretion, and bioavailability of AFB(1)in vivo, turkeys were given diets with BHT (4000ppm) for 10 days, given a single oral dose of [(3)H]-AFB(1) (0.05microg/g; 0.02microCi/g), then sampled at intervals up to 24h. Radiolabel in serum, red blood cells, liver, and breast meat was frequently lower in BHT-treated compared to control. Hepatic AFB(1)-DNA adducts in BHT-treated turkeys were significantly lower at 12 and 24h. BHT-fed birds had significant higher bile efflux, though biliary radiolabel excretion was not different from control. The amount of aflatoxin M(1) (AFM(1)) excreted in the bile was lower than in control, but BHT had no effect on the biliary excretion of AFB(1), aflatoxin Q(1) or glucuronide and sulfate conjugates. Thus, the chemopreventive properties of BHT may also occur through a reduction in AFB(1) bioavailability in addition to inhibition of bioactivation.

New analogues of butylated hydroxytoluene as anti-inflammatory and antioxidant agents.

Amine or amide derivatives bearing the 2,6-di-tert-butyl phenol moiety are synthesised. Almost all are antioxidants, reduce acute inflammation and inhibit COX-1 and lipoxygenase activity. The most potent anti-inflammatory, COX-1 inhibitor and antioxidant agent, with low toxicity, is 2,6-di-tert-butyl-4-thiomorpholin-4-ylmethyl-phenol.

Attenuation of the pulmonary inflammatory response following butylated hydroxytoluene treatment of cytosolic phospholipase A2 null mice.

Administration of butylated hydroxytoluene (BHT) to mice causes lung damage characterized by the death of alveolar type I pneumocytes and the proliferation and subsequent differentiation of type II cells to replace them. Herein, we demonstrate this injury elicits an inflammatory response marked by chemokine secretion, alveolar macrophage recruitment, and elevated expression of enzymes in the eicosanoid pathway. Cytosolic phospholipase A(2) (cPLA(2)) catalyzes release of arachidonic acid from membrane phospholipids to initiate the synthesis of prostaglandins and other inflammatory mediators. A role for cPLA(2) in this response was examined by determining cPLA(2) expression and enzymatic activity in distal respiratory epithelia and macrophages and by assessing the consequences of cPLA(2) genetic ablation. BHT-induced lung inflammation, particularly monocyte infiltration, was depressed in cPLA(2) null mice. Monocyte chemotactic protein-1 (MCP-1) content in bronchoalveolar lavage fluid increases after BHT treatment but before monocyte influx, suggesting a causative role. Bronchiolar Clara cells isolated from cPLA(2) null mice secrete less MCP-1 than Clara cells from wild-type mice, consistent with the hypothesis that cPLA(2) is required to secrete sufficient MCP-1 to induce an inflammatory monocytic response.

Therapeutic options for herpes labialis: experimental and natural therapies.

Herpes labialis, a common condition characterized by recurrent vesicular eruptions primarily on the lips and perioral skin, causes pain and discomfort for millions of adults each year. Over the past several years, the major focus of herpes research has been on the treatment of genital herpes. However, several studies have been conducted to evaluate the efficacy of therapies specifically for herpes labialis. Last year in Cutis, we reviewed oral and topical therapies for herpes labialis. In this final part of the series, we review experimental and natural treatments that are available for herpes labialis and its associated symptoms.

Pro-oxidant and anti-oxidant mechanism(s) of BHT and beta-carotene in photocarcinogenesis.

An hypothesis for the role of free radicals in cancer was elaborated by D. Harman in 1962 who suggested that it might be possible to reduce the extent of damage caused by free radicals through three dietary changes: (i) caloric reduction, i.e., lowering the level of free radical reactions arising in the course of normal metabolism; (ii) minimize dietary components that tend to increase the level of free radical reactions (e.g., polyunsaturated fats); and (iii) supplement the diet with one or more free radical reaction inhibitors (anti-oxidants). With respect to (ii) and (iii), lipid peroxidation exemplifies the type of chain reaction initiated by free radicals, with unsaturated fatty acids being the primary center of free radical attack. Anti-oxidants act as free radical scavengers and are able to terminate these reactions. Indeed, the phenolic anti-oxidant butylated hydroxytoluene (BHT), and the carotenoid beta-carotene, have both been shown to influence photocarcinogenesis, although the lack of correlation between physicochemical parameters and pathophysiological responses is apparent in both instances. The bimolecular rate constant for reaction of BHT with model peroxyl radicals is low while beta-carotene is highly reactive. However, both are able to efficiently inhibit lipid peroxidation reactions in biological membranes. Indeed, the influence of photocarcinogenesis by both BHT and beta-carotene is diminished as the level of dietary fat decreases, pointing to the involvement of lipid peroxidative reactions. Nevertheless, the mode of action of BHT in inhibiting photocarcinogenesis appears to be related to dose-diminution resulting from an increased spectral absorbance of the stratum corneum. On the other hand, beta-carotene has no such effect and may actually exacerbate photocarcinogenesis under certain dietary conditions. This paradox points to the complex relationship between chemical mechanisms and biological mode of action of anti-oxidants in photocarcinogenesis. Recent clinical and experimental data also suggest that supplementation of the complex and intricately balanced natural antioxidant defense system with one or more anti-oxidants as a cancer prevention strategy will demand extreme caution.

[The effect of semax and mexidol on the course of acute pancreatitis in rats]. / Vliianie semaksa i meksidola na techenie ostrogo pankreatita u krys.

The effect of semax and mexidol on the course of acute pancreatitis in rats was studied in comparison with the action of contrical, fluorouracil, and dibunol. It was established that a single intraductal or intraperitoneal administration of semax or mexidol markedly reduces the loss of experimental animals (to 10-13%), decreases hyperfermentemia, lipid peroxidation activation, and vascular permeability, improves microcirculation, and accelerates healing of the damaged pancreatic zones by substitutional repair of pancreatic acini not accompanied by coarse fibrous changes in the parenchyma. Upon the intraductal administration, semax and mexidol were more effective than contrical, fluorouracil, and dibunol.

Antioxidant LY231617 enhances electrophysiologic recovery after global cerebral ischemia in dogs.

OBJECTIVE: The potent antioxidant LY231617 (2,6-bis(1,1-dimethylethyl)-4-[[(1-ethyl)amino]methyl]phenol hydrochloride) is cytoprotective in models of focal and global cerebral ischemia. We tested the hypothesis that administration of LY231617, before the insult, would improve recovery of cerebral electrical activity and metabolic function after transient global cerebral ischemia by improving cerebral blood flow (CBF) during the reperfusion period. DESIGN: Randomized, controlled, prospective study. SETTING: Research laboratory at a university teaching hospital. SUBJECTS: Twenty-four male beagle dogs. INTERVENTIONS: All experiments were performed under pentobarbital anesthesia and controlled conditions of normoxia, normocarbia, and normothermia. Twelve control dogs received 20 mL/kg saline (vehicle) bolus into the right atrium and 0.01 mL/kg/min i.v., beginning 20 mins before 13 mins of global cerebral ischemia (by aortic occlusion). The dogs in the drug-treated group received LY231617 as a 10-mg/kg bolus 20 mins before ischemia and 5 mg/kg/hr throughout reperfusion (n = 12). CBF was measured using radiolabeled microspheres. MEASUREMENTS AND MAIN RESULTS: Total CBF, cerebral oxygen consumption, and somatosensory evoked potentials (SEP) were measured during 240 mins of reperfusion. CBF was similar in both vehicle- and LY231617-treated animals at baseline and throughout the experimental period. In all animals, SEP became isoelectric between 60 and 100 secs after cross-clamping of the ascending aorta. SEP amplitude recovery was significantly higher in drug-treated animals compared with controls (73%+/-15% vs. 39%+/-14% [mean+/-SEM] from baseline at 120 mins [p<.05] and 86%+/-12% vs. 49%+/-14% from baseline at 240 mins [p< .05]). CONCLUSIONS: LY231617 improves recovery of cerebral electrical function after complete transient global ischemia via mechanisms unrelated to cerebral circulatory effects.

[Effectiveness of synthetic antioxidants in treatment of patients with peptic ulcer (an open randomized controlled trial)]. / Izuchenie éffektivnosti sinteticheskikh antioksidantov v lechenii bol'nykh iazvennoi bolezn'iu (otkrytoe kontrolirovannoe randomizirovannoe issledovanie).

Two randomized groups of ulcer patients were compared. 102 patients of group 1 were treated with synthetic antioxidants (dibunol, probucol, emoxipine), while 100 patients of group 2 received a conventional treatment. Treatment results in group 1 appeared better: shortening of ulcer scarring, higher percentage of ulcer healing for 2 and 4 weeks, fall in the number of relapses during the first year of the follow-up, improvement in lipid peroxidation and antioxidant activity.

[Changes in the oxygen-binding properties of the blood in white rats under the influence of hypoxia and its pharmacological correction]. / Zminy kysnevozv'iazuiuchykh vlastyvostei krovi u bilykh shchuriv pid vplyvom hipoksiï ta ïï farmakolohichnoï korektsiï.

It was shown that acute (7% of oxygen in nitrogen, 30-60 min) and chronic hypoxic hypoxia (adaptation to the conditions of the middle mountains 2100 m above sea level) increased hemoglobin contents and organic phosphates--2,3-DPG and ATP in Wistar rats. Preliminary administration of taurine, taurile, ionole in normal and hypoxic conditions had no essential effect on the oxygen blood capacity where as the content of 2,3-DPG and glucoso-6-phosphate dehydrogenase activity increased. Taurin was more effective, than tauril.

[The anti-ulcer action of dibunol (Tonarol)]. / Protivoiazvennoe deistvie dibunola (tonarola).

In experimental study of antiulcerative activity of dibunol on various models of gastric ulcers in rats the drug caused a marked antiulcerative effect in all of them, reduced the incidence of ulcer formation, and shortened the time of ulcer healing. In a model of "acetic" ulcer dibunol oil solution led to quick normalization of lipid peroxidation in the gastric mucosa, which was evidence of high antioxidant activity in cases of ulcer lesions.

Dietary antioxidants do not reduce fatty streak formation in the C57BL/6 mouse atherosclerosis model.

Epidemiological studies and animal trials have suggested that dietary antioxidants protect against atherosclerosis. To test this hypothesis, C57BL/6 mice were fed atherogenic diets supplemented with either vitamin E or butylated hydroxytoluene (BHT). Three groups of 20 mice were fed for 15 weeks on diets containing 1% cholesterol and 0.5% cholic acid. The diet of two groups was supplemented with either 2% vitamin E or 1% BHT. The control group received no antioxidant supplements. The lowest mean serum cholesterol concentration was measured in mice supplemented with vitamin E. Mean serum HDL cholesterol concentrations were highest in the control group, which also had the highest ratio of HDL cholesterol to total cholesterol. Mice fed BHT developed a significantly greater area of aortic fatty streak lesions than the other two groups. However, despite having a more atherogenic lipoprotein profile, mice fed vitamin E developed a level of fatty streak formation similar to the control group. At the end of the trial, mice consuming the vitamin E- and BHT-supplemented diets had higher serum total antioxidant levels than the control mice. Because of changes to lipid metabolism caused by both vitamin E and BHT, the results of this study cannot be used to support the hypothesis that antioxidants confer protection against atherosclerosis. The results do, however, raise the possibility that other studies demonstrating an antiatherogenic action of vitamin E and BHT may have been influenced by their effects on lipid metabolism.

Effects of butylated hydroxytoluene (BHT) enriched diet on serum antioxidant activity in pre-and overtly diabetic nod mice.

Preventive (antioxidant activity) and chain-breaking (total peroxyl radical-trapping parameter) antioxidants in the serum of controls and butylated hydroxytoluene (BHT)-diet enriched nonobese diabetic (NOD) and C57B16/J mice from 5 to 25 weeks of age are measured in this study. A significant decrease in the overall potency of both antioxidant types is demonstrated in NOD untreated controls but not in animals whose diet was BHT-enriched. Therefore, we show that alterations of the antioxidant status in NOD mice is efficaciously counteracted by BHT.

[The effect of phenol antioxidants on the development of alloxan diabetes in rats]. / Vliianie fenol'nykh antioksidantov na razvitie alloksanovogo diabeta u krys.

Experiments were conducted on an alloxan diabetes model to study the preventive effects of the phenol antioxidants ionol and probucol. Ionol showed a tendency towards inhibition of glycemia and free radical oxidation of lipids. Probucol effectively inhibited the development of glycemia, hyperlipidemia, and intensification of autooxidation in the vascular wall. On the grounds of the results it is concluded that inclusion of probucol into complex treatment of patients suffering from diabetes mellitus with vascular complications is expedient.

Induction of sulfated glycoprotein-2 (clusterin) and glial fibrillary acidic protein (GFAP) RNA expression following transient global ischemia is differentially attenuated by LY231617.

Sulfated glycoprotein-2 (SGP-2) is a secreted glycoprotein that along with GFAP has emerged as a prominent molecular marker of neurodegeneration. In the present study, we have evaluated further the relationship between SGP-2, GFAP and neurodegeneration, by examining the effects of LY231617, a potent antioxidant, on expression of SGP-2 and GFAP following four vessel occlusion (4VO). GFAP and SGP-2 RNA levels increased several fold in hippocampus and caudate nucleus in response to 30 min of 4VO. LY231617 treatment markedly attenuated the induction of GFAP RNA in both hippocampus and caudate nucleus, consistent with the significant neuroprotection observed histologically. In contrast, LY231617 treatment blunted SGP-2 RNA expression only in the hippocampus; SGP-2 RNA expression in caudate nucleus was similar to vehicle-treated 4VO, despite the marked attenuation of neuronal damage in both areas by LY231617. These data suggest region-specific differential regulation of SGP-2 and GFAP RNA induction.