Addition Of Butylated Hydroxytoluene Research Articles

Influence of an anti-oxidant on the formation of allergenic compounds during auto-oxidation of d-limonene.

Butylated hydroxytoluene (BHT), a common anti-oxidant, was added to different samples of d-limonene. The decrease in concentration of d-limonene and the formation of oxidation products were compared between the samples and with samples without anti-oxidant using gas chromatography. The aim of the study was to investigate how long d-limonene to which BHT was added could be handled when air-exposed at room temperature, without formation of oxidation products which according to previous studies increase the risk of skin sensitization. In experiments trying to mimic the handling of limonene products at workplaces the addition of BHT prevented auto-oxidation for periods depending on the purity of the products and on the room temperature. Cold and dark storage of d-limonene in closed vessels prevented auto-oxidation for 1 year without addition of anti-oxidant.

Butylated hydroxytoluene prevents cumene hydroperoxide-induced Ca 2+ release from liver mitochondria by inhibiting pyridine nucleotide hydrolysis

The mechanism by which the free radical scavenger butylated hydroxytoluene (BHT) prevents cumene hydroperoxide-induced Ca 2+ release from rat liver mitochondria was studied. In Ca 2+-loaded mitochondria cumene hydroperoxide induced a rapid oxidation and subsequent hydrolysis of the pyridine nucleotides. In the presence of BHT, pyridine nucleotide oxidation by cumene hydroperoxide occurred but was reversible as hydrolysis was prevented by BHT. However, the addition of BHT directly to rat liver submitochondrial particles did not inhibit NAD + hydrolysis or the formation of ADP-ribose from NAD +. Thus, whilst BHT prevented NAD + hydrolysis in isolated mitochondria, this appeared not to be due to a direct effect of BHT on the NADase. It is concluded that the mechanism of action of BHT on cumene hydroperoxide-induced Ca 2+ release from mitochondria involves the inhibition of pyridine nucleotide hydrolysis by an indirect mechanism rather than the radical scavenging properties of BHT.

Effects of treatment with butylated hydroxytoluene on the susceptibility of boar spermatozoa to cold stress and dilution.

Boar spermatozoa acquired resistance to cold shock immediately after exposure to 2.0 mmol butylated hydroxytoluene (BHT) l-1 when Beltsville thawing solution was used as a basic diluent, as judged by motility (the proportion of motile spermatozoa) and acrosomal integrity. The concentration of BHT could be reduced to 0.2 mmol l-1 without decreasing the protective action. However, motility was altered in the presence of greater than 0.15 mmol BHT l-1. Beltsville freezing 5 (BF5) diluent was more effective than Beltsville thawing solution in protecting spermatozoa from cold shock, but addition of BHT to BF5 diluent did not affect the motility and acrosomal morphology of spermatozoa before or after cold shock. Dilution of BHT-treated spermatozoa with BF5 diluent did not restore motility and did not afford further protection against cold shock; it was detrimental to spermatozoa treated with 2 mmol BHT l-1 for greater than 15 min. Egg yolk or lecithin had a detrimental effect. When spermatozoa were treated with 0.05-0.10 mmol BHT l-1 before slow cooling to 5 degrees C, the progressive motility and acrosomal integrity were maintained better after storage for 6 days than in untreated spermatozoa.

The antioxidant butylated hydroxytoluene protects against atherosclerosis.

Rabbits fed a 1% cholesterol diet with or without the antioxidant butylated hydroxytoluene (BHT) developed typical atherosclerotic lesions. The addition of BHT gave higher levels of total cholesterol (+40%), triglycerides (+250%), low density lipoprotein (LDL), and very low density lipoprotein (VLDL) in plasma. Despite the lower plasma lipid levels, the degree of atherosclerosis of the aortic surface was considerably higher in rabbits fed cholesterol than in the group treated with cholesterol and BHT. The mean atherosclerotic involvement was 18.6 +/- 4.4% in the former group and 5.9 +/- 1.7% in the latter group (p = 0.02). In all animals, there was a high correlation between the area of the arterial lesion and cholesterol content (r = 0.96). Serum levels of cholesterol autooxidation products (7-ketocholesterol and cholesterol 5 alpha,6 alpha-epoxide) were lower in the group of rabbits treated with BHT (p less than 0.005). Serum levels of vitamin E were slightly higher in the BHT group. There was no significant difference in the clearance of beta-VLDL between the two treatment groups after using either beta-VLDL from cholesterol-fed animals or beta-VLDL from BHT-fed animals. The results are in accord with the contention that oxidative modification of lipoproteins is important for the development of atherosclerosis and that antioxidants may have a protective effect. At present, however, other explanations cannot be completely excluded, for example, effects of antioxidants on immunologic factors or monocyte adhesion.

Mechanisms of butylated hydroxytoluene-mediated modulation of 2-acetylaminofluorene mutagenicity in rat and human hepatocyte/Salmonella assays

Salmonella typhimurium (TA98) mutagenesis assays were used to study the influence of the antioxidant butylated hydroxytoluene (BHT) on 2-acetylaminofluorene (2-AAF) mutagenesis, in search of the mechanism of the anticarcinogenic effects of BHT. Rats pre-treated with BHT in the diet (0.5% w/w for 10 days) provided hepatocytes and hepatocyte S9 which were more efficient in the activation of 2-AAF than were similar preparations from control rats. The increased release of mutagens from hepatocytes might explain the reported increase in the incidence of bladder tumours in BHT-treated rats. In contrast, the mutagenic activity of 2-AAF was inhibited by the in vitro addition of BHT into incubations where human or rat liver S9 and intact hepatocytes were used for metabolic activation. Both competitive and un-competitive inhibition by BHT of 7-ethoxycoumarin O-deethylation was observed in hepatocytes which suggested that the antimutagenic activity may be mediated by one or more mechanisms of cytochrome P-450 inhibition. BHT inhibition of the mutagenicity of N-OH 2-AAF and of rat urinary metabolites of 2-AAF indicated that effects other than those mediated by cytochrome P-450 also occur e.g. scavenging of reactive metabolites. It was concluded that BHT-modulation of 2-AAF metabolic activation and mutagenesis (which may relate to BHT-protection against hepatocarcinogenicity) involves multiple mechanisms.

Butylated hydroxytoluene addition improves the thiobarbituric acid assay for malonaldehyde from chicken plasma fat.

Samples of plasma lipid were tested for autoxidation during the heating step of the thiobarbituric acid (TBA) assay for malonaldehyde. Butylated hydroxytoluene (BHT) was used to quench sample autoxidation during the assay, and 25 ppm BHT was found effective in eliminating autoxidation in fresh plasma fat. At this concentration, BHT does not interfere with the reaction of malonaldehyde with TBA. Depending on fat concentration, absorbance at 532 nm was 2-5 times higher when samples were assayed without BHT compared to identical samples with 25 ppm BHT addition. It is concluded that BHT addition to the TBA assay before the heating step improves the reliability of the assay by eliminating autoxidation which may generate the majority of oxidative products measured in TBA assays lacking antioxidant protection.

Studies on the antioxidants. XVI. Synergistic reaction between butylated hydroxyanisole and butylated hydroxytoluene in hydrogen donation to 2,2-diphenyl-1-picrylhydrazyl.

Hydrogen-donating processes of combined antioxidants, butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT), were followed by using 2, 2-diphenyl-1-picrylhydrazyl (DPPH) as the hydrogen acceptor, and their relation to the synergism is discussed. The hydrogen donation to DPPH by BHA was almost complete in 10 min. DPPH and BHA were regenerated from this reaction mixture by addition of DPPH·H in the molar ratio of 2 : 1, and BHA and 2, 6-di-tert-butylquinone methide (QM) were formed by addition of BHT in the molar ratio of 1 : 1. The phenoxy radical formed from BHA was lost upon further addition of DPPH. These results suggest the formation of a stable intermediate which accepts two hydrogens from BHT to regenerate BHA, and the possible reaction processes of BHA and BHT with DPPH are shown as Chart 1 ; BHA reacts with DPPH to form the stable intermediate via its phenoxy radical, and this intermediate reacts with BHT to regenerate BHA with the enhanced oxidation of BHT to QM via its phenoxy radical. These processes may be associated with the synergism between BHA and BHT in hydrogen donation to DPPH. The amount of loss of DPPH was in fair agreement with the sum of two hydrogens donated by BHT in the enhanced oxidation to QM and hydrogens donated by BHA. The rate of decrease in DPPH concentration by BHA was about 450 times that by BHT.

Improved Procedure for the Estimation of Nanogram Quantities of Indole-3-acetic Acid in Plant Extracts using the Indolo-α-pyrone Fluorescence Method

The indolo-alpha-pyrone fluorescence method of determining indole-3-acetic acid (IAA) is improved by adding butylated hydroxytoluene (BHT), an antioxidant, to samples: addition of BHT increases the fluorescence intensities and decreases their variability so that amounts of IAA as small as 0.1 to 1 nanogram become measurable. Interfering compounds, 4-chloroindole-3-acetic acid and 5-hydroxyindole-3-acetic acid, can be separated from IAA by thin-layer chromatography using polyamide as the solid support, and benzene-ethyl acetate-acetic acid (70:25:5, v/v) as the developing solvent. Polyamide thin-layer chromatography is also superior in purifying IAA without significant loss or decomposition.A serious problem in extracting IAA from plant tissues is the considerable loss. Losses can result from decomposition of IAA when its solutions in organic solvents are evaporated to dryness, apparently due to some impurity in the solvents. Decomposition can be eliminated by simple treatments of the solvents, i.e. addition of BHT, washing with water, and passage through cotton wool. The latter is particularly effective in the case of ethyl acetate and ether. Loss of IAA by photodecomposition is also substantial even in dried samples. Ways to minimize the conversion of indole-3-pyruvic acid to IAA during extraction procedure are also described.A revised procedure of IAA extraction and determination is proposed. Applied to etiolated shoots of maize seedlings, it enables content to be estimated (18 nanograms per gram fresh weight) with over 90% recovery in terms of [(14)C]IAA added at the beginning of the extraction.

The effects of butylated hydroxytoluene on the cell cycle and chromosome morphology of phytohaemagglutinin-stimulated leucocyte cultures

Butylated hydroxytoluene (BHT) was introduced in various concentrations (0–50 μg/ml of culture medium) into phytohaemagglutinin-stimulated human leucocyte cultures while these cells were in their rapidly dividing phase. Monitoring of the cell cycle immediately after addition of this food preservative suggested that BHT caused a shortening of the cycle in surviving cells, the effect increasing with an increase in dose. This initial response seemed to be followed by a slight lag in the cells' ability to enter the subsequent mitosis. Addition of BHT also resulted in a dose-related decrease in cell survival, as monitored by the ability of the cultured cells to incorporate [ 3H] thymidine, as well as in an uncoiling of the chromosomes and extensive cell-membrane damage to the transformed cells.

The Effects of Santoquin on the Performance of Broilers

THE use of antioxidants in broiler feeds, in an effort to improve xanthophyll utilization, has produced conflicting results. Wilgus (1954), Potter et al. (1956) and Fritz et al. (1957) reported that the addition of DPPD (diphenyl-p-phenylenediamine) to the feed resulted in an increased deposition of yellow pigment in the skin and shanks of broilers. Potter et al. (1956) and Elrod et al. (1958) reported a slight improvement in pigmentation when BHT (Butylated-hydroxytoluene) was added to the feed. Day and Williams (1958) found that the addition of BHT to broiler feed reduced somewhat the pigmentation of broilers, but this difference was not significant except in two groups in one trial. Harms et al. (1958) found that the addition of DPPD to the diet significantly decreased the pigmentation in the skin of broilers.Santoquin* (hereafter referred to by the generic term ethoxyquin), an antioxidant recently approved for use in poultry feeds, has …