Effect of butylated hydroxytoluene (BHT) concentrations on polymerization shrinkage stress and other physicochemical properties of experimental resin composites.

The present study examined different concentrations of the butylated hydroxytoluene (BHT) inhibitor on the kinetics of conversion, polymerization shrinkage stress, and other correlated physicochemical properties of experimental resin composites (ERC). A model composite was formulated with 75 wt% filler containing 0.5 wt% camphorquinone and 1 wt% amine with BHT concentrations of 0.01 wt% (BHT-0.01); 0.1 wt% (BHT-0.1); 0.25 wt% (BHT-0.25); 0.5 wt% (BHT-0.5); 1 wt% (BHT-1), and control (no BHT). They were tested on polymerization shrinkage stress (PSS; n = 5), degree of conversion (DC; n = 3), maximum polymerization rate (RpMAX; n = 5), water sorption (Wsp; n = 0), and solubility (Wsl; n = 10), flexural strength (FS; n = 10), flexural modulus (FM; n = 10), Knoop microhardness (KH; n = 10), and microhardness reduction (HR; n = 10). Data concerning these tests were submitted to one-way ANOVA and Tukey's test (α = 0.05; ß = 0.2). BHT-0.25, BHT-0.5, and BHT-1 showed a gradually significant decrease in PSS (p = 0.037); however, BHT-1 demonstrated a decrease in the physicochemical properties tested. Thus, within the limitations of this study, it was possible to conclude that BHT concentrations between 0.25 and 0.5 wt% are optimal for reducing shrinkage stress without affecting other physicochemical properties of ERCs.

Detection of Synthetic Antioxidants: What Factors Affect the Efficiency in the Chromatographic Analysis and in the Electrochemical Analysis?

Antioxidants are food additives largely employed to inhibit oxidative reactions in foodstuffs rich in oils and fat lipids, extending the shelf life of foodstuffs and inhibiting alterations in color, flavor, smell, and loss of nutritional value. However, various research has demonstrated that the inadequate use of synthetic antioxidants results in environmental and health problems due to the fact that some of these compounds present toxicity, and their presence in the human body, in high concentrations, is related to the development of some cancer types and other diseases. Therefore, the development of analytical methods for identifying and quantifying synthetic antioxidants in foodstuffs is fundamental to quality control and in ensuring consumer food safety. This review describes the recent chromatographic and electrochemical techniques used in the detection of synthetic phenolic antioxidants in foodstuffs, highlighting the main characteristics, advantages and disadvantages of these methods, and specific typical features, which include extraction methods for sample preparation and materials used in the working electrode construction, considering chromatographic and voltammetric methods, since these specific features influence the efficiency in the analysis.

Effect of a polymerization inhibitor on the chemomechanical properties and consistency of experimental resin composites

Abstract This study investigated the effect of butylated hydroxytoluene (BHT) inhibitor on degree of conversion (DC), flexural strength (FS), flexural modulus (FM), Knoop microhardness (KH), microhardness reduction (HR), and consistency of experimental resin composites at different BHT concentrations: C0 (control-0%); C0.01 (0.01%); C0.025 (0.025%); C0.05 (0.05%); C0.1 (0.1%); and C0.5 (0.5%). For the consistency, the composites were tested immediately after being exposed to a dental chair headlight (0, 20, 40 and 60 s). Data concerning DC, FS, FM, KH, and HR were submitted to one-way ANOVA, while the consistency data was submitted to 2-way ANOVA; mean values were then compared (Tukey's test; α=0.05). The KH, FS and FM analyses showed no significant difference among the composites tested. For DC, C0 showed the highest mean value (74.2%) and differed only from C0.5 (67.2%). For HR, C0.5 showed the lowest mean (13.09%) value and differed from C0 (26.4%) and C0.01 (24.87). The consistency analysis showed no difference among C0.05, C0.1 and C0.5, considering 0 and 20 s of light exposure, while C0 (14.07 mm), C0.01 (13.97 mm), and C0.025 (14.18 mm) showed higher mean values at 0 s when compared to 20 s (12.67, 12.77 and 13.05 mm, respectivelly). Polymerization occurred within 40 s of light exposure for C0, C0.01, C0.025, and C0.05 and within 60 s for C0.1. In conclusion, the BHT concentrations had no significant influence on FS, FM and KH. The higher the BHT concentration, the longer was its handling time under light, with a significant improvement in the HR, but a decrease in DC. Therefore, BHT at 0.1% showed the best outcomes concerning all the BHT concentrations tested.

Resumo O objetivo foi investigar o efeito do inibidor de polimerização BHT no grau de conversão (GC), resistência à flexão (RF), módulo de flexão (MF), microdureza Knoop (KH) e redução da microdureza (RKH), e consistência de um compósito experimental contendo diferentes concentrações de BHT (% em peso): C0 - controle (0%); C0,01 (0,01%); C0,025 (0,025%); C0,05 (0,05%); C0,1 (0,1%); e C0,5 (0,5%). Para o teste de consistência, os compósitos foram testados imediatamente após serem expostos à luz de um refletor odontológico por 0, 20, 40 e 60 s. Os dados relativos a GC, RF, MF, KH e RKH foram submetidos a one-way ANOVA, enquanto os dados de consistência foram submetidos a two-way ANOVA; os valores médios foram comparados (teste de Tukey; α = 0,05). As análises de KH, RF e MF não mostraram diferença significativa entre os compósitos testados. Para GC, C0 apresentou o maior valor médio e diferiu apenas de C0,5. Para a RKH, C0,5 apresentou o menor valor médio e diferiu de C0 e C0,01. A análise de consistência não mostrou diferença entre C0,05, C0,1 e C0,5, considerando-se 0 e 20 s de exposição à luz, enquanto C0, C0,01 e C0,025 apresentaram maiores valores médios a 0 s quando comparados a 20 s. A polimerização ocorreu dentro de 40 s de exposição à luz para C0, C0.01, C0.025 e C0.05 e dentro de 60 s para C0.1. Em conclusão, as concentrações de BHT não tiveram influência significativa sobre RF, MF e KH. Quanto maior a concentração de BHT, maior o tempo de manuseio sob luz, com melhora significativa da RKH, mas diminuição da GC. Portanto, o compósito contendo 0,1 % de BHT apresentou os melhores resultados entre as demais concentrações testadas.

Addition of a blend of essential oils (cloves, rosemary and oregano) and vitamin E to replace conventional chemical antioxidants in dog feed: effects on food quality and health of beagles.

This study aimed to produce dog food containing natural antioxidants (blend of essential oils and vitamin E) to replace synthetic antioxidants and determine the effects on food conservation and animal health sequentially. The foods were produced in a commercial factory, and the antioxidants were added at the oil bath stage. Ten adult beagle dogs were used, divided into two treatments; control treatment (CON; synthetic antioxidant feed [butylhydroxytoluene]) and test treatment (NAT; natural antioxidant feed; blend of essential oils from clove, rosemary, oregano, and vitamin E). The dogs were weighed at the beginning and end of each experimental period, and there were no treatment effects for body weight. In both treatments, food conservation efficiency was observed, demonstrating the feasibility of using natural sources as antioxidants in dog food because chemical and oxidative variables did not differ regardless of the antioxidant used during production. The animals' metabolic and haematological variables were not influenced by the treatments; however, a reduction in the number of lymphocytes was observed over time only in the dogs of the NAT group. There was also a day effect for total leukocyte, neutrophil and erythrocyte counts only in NAT animals, which means a significant increase (p ≤ 0.05) in the variables on d 28. There was an effect of the treatment and an interaction treatment x day for the total bacterial count, whereas a decrease in the bacterial count (p < 0.05) was observed in NAT dogs' faeces on day 28. Dogs fed the NAT diet had lower reactive oxygen species (ROS) (p ≤ 0.05) to minimise oxidative stress. In group NAT, the NPSH and glutathione S-transferase levels were increased, which may explain the decrease in ROS levels. It was concluded that natural antioxidants in dog feed, in addition to promoting feed conservation, stimulate levels of systemic antioxidants and minimise the impacts caused by free radicals in the dogs' blood.

Pomegranate (Punica granatum) peel fractions obtained by supercritical CO2 increase oxidative and colour stability of bluefish (Pomatomus saltatrix) patties treated by UV-C irradiation.

The sequential fractionation by supercritical-CO2 (SC-CO2) was applied to obtain fractions enriched in bioactive compounds of pomegranate peel, and we investigated if pomegranate peel extract and fractions would be effective to inhibit lipid and protein oxidation, and discolouration of bluefish patties stored at 4 °C for 9 days, after UV-C irradiation. The non-fractionated SC-CO2 extract from pomegranate peel was rich in phenolic compounds, mainly ellagitannins, besides, it possessed lipophilic compounds such as tocopherols and ß-carotene. These compounds were successfully separated by the fractionation protocols, in a lipid fraction concentrated in lipophilic compounds, and one or two fractions enriched with phenolic compounds, especially ellagitannins. The lipid fraction and the high phenolics fraction from pomegranate peel were then as effective as the synthetic antioxidant BHT in avoiding bluefish patties oxidation during refrigerated storage. Our data indicates that pomegranate peel fractions could be used to replace a synthetic antioxidant in fish meat.

Short-term storage sperm of coho salmon (Oncorhynchus kisutch) at 4 °C: Effect of sperm: Extender dilution ratios and antioxidant butyl-hydroxytoluene (BHT) on sperm function.

Short-term storage of semen is a necessary key procedure in fish; it allows maximizing the use of gametes. Nevertheless, sperm quality decreases during storage has been associated with oxidative stress damage due to an increase in reactive oxygen species (ROS) during storage. This study was designed to optimize a short-term storage protocol for Coho salmon (Oncorhynchus kisutch) spermatozoa, evaluating the effect of extender dilution and the addition of butyl-hydroxytoluene (BHT) antioxidant on sperm function parameters. In the first experiment, fresh semen was diluted in Storfish®: extender dilution (1:2 and 1:3) and a control sample undiluted and stored at 4 °C for 7-days. In both experiments motility (MO), viability and integrity of plasma membrane, mitochondrial membrane potential (MMP) and superoxide anion level (O2-) were evaluated at 0, 3 and 7 days. Result shows that, 1:3 dilution maintained a higher sperm function for a longer period time. In the second experiment, spermatozoa were suspended in Storfish® (1:3) supplemented with two different concentrations of BHT (1.0 mM and 2.0 mM) and a control sample without antioxidant and stored at 4 °C for 7 days. The results demonstrated that, antioxidant-supplemented samples greater MO than control samples (P < 0.05). The viability remained >75% during storage in all groups. MMP was higher in 2.0 mM BHT compared to 1.0 mM and control (P < 0.05), in addition, this concentration reduced O2- level (P < 0.05). In conclusion, sperm: extender dilution 1:3 and adding of 2.0 mM BHT in sperm storage extender may enhance protection sperm function in Oncorhynchus kisutch against effects harmful of the oxidative stress during the in vitro storage.

Positive effect of butylated hydroxytoluene (BHT) on the quality of cryopreserved cat spermatozoa.

The semen cryopreservation processes are associated with state of oxidative stress induced by high levels of reactive oxygen species (ROS), causing damage to functional spermatozoa. Whereby, antioxidants have been utilized to scavenge or neutralize the elevated levels of ROS. The aim of at the present study was to evaluate the effect of adding BHT to the freezing extenders on post-thaw characteristics of domestic cat spermatozoa. Semen samples were frozen in Tris-fructose-citric acid-based extender, supplemented with different concentrations of BHT (0.5 mM, 1.0 mM and 2.0 mM) and a control sample without antioxidant. After thawing, sperm samples were assessed for motility by computer-assisted sperm analysis and viability, acrosome integrity, superoxide anion production and membrane lipid peroxidation status by flow cytometry. In the study, the parameters of sperm motility and acrosome integrity were significantly higher in 2.0 mM BHT compared to sperm frozen in the extender with other concentrations and control (P < 0.05), in addition, this concentration reduced significantly the superoxide anion production and lipid peroxidation of the sperm. The results demonstrated that the supplementation of BHT to the freezing extender could protect the function and cellular structure of domestic cat sperm from cryoinjuries.

Evaluation of oxidative stability of mayonnaise containing poly ε- caprolactone nanoparticles loaded with thyme essential oil

Suspensions of poly ε-caprolactone (PCL) nanoparticles loaded with thyme essential oil were prepared as a natural antioxidant in mayonnaise. Mean particle size was 204.9 ± 2.7 and 240.0 ± 5.5 nm respectively for nanoparticles prepared with PCL alone (NP-C) and for those loaded with thyme essential oil (NP-T). The polydispersity index indicated a homogeneous distribution of all particles, with no significant difference between NP-C and NP-T samples. The nanoparticles showed a large negative charge evidenced by zeta potential rates, indicating high physical stability. The use of PCL as a polymer provided high encapsulation efficiency for thyme essential oil (91.15 ± 2.12 %). DPPH (2,2-diphenyl-1-picrylhydrazyl) method determined IC50 rates were 476.4 ± 33.6 and 483.5 ± 20.4 µg mL-1respectively for unencapsulated oil and for NP-T, evidencing pronounced antioxidant activity. NP-C, NP-T and synthetic antioxidant butylhydroxytoluene (BHT) were applied to samples of mayonnaise and their oxidative stability evaluated for eight days in an oven at 63 ± 3ºC. Results of hydroperoxide value (HP) and thiobarbituric acid reactive substances (TBARS) showed that NP-T had a similar performance as synthetic antioxidant BHT in the prevention of mayonnaise lipid oxidation

Phenolic profile and antioxidant activity from non-toxic Mexican Jatropha curcas L. shell methanolic extracts.

Jatropha curcas seed shells are the by-product obtained during oil extraction process. Recently, its chemical composition has gained attention since its potential applications. The aim of this study was to identify phenolic compounds profile from a non-toxic J. curcas shell from Mexico, besides, evaluate J. curcas shell methanolic extract (JcSME) antioxidant activity. Free, conjugate and bound phenolics were fractionated and quantified (606.7, 193.32 and 909.59 µg/g shell, respectively) and 13 individual phenolic compounds were detected by HPLC. The radical-scavenging activity of JcSME was similar to Trolox and ascorbic acid by DPPH assay while by ABTS assay it was similar to BHT. Effective antioxidant capacity by ORAC was found (426.44 ± 53.39 µmol Trolox equivalents/g shell). The Mexican non-toxic J. curcas shell is rich in phenolic compounds with high antioxidant activity; hence, it could be considerate as a good source of natural antioxidants.

Evaluation of antioxidant and mutagenic activities of honey-sweetened cashew apple nectar.

In vitro chemical properties and antioxidant potential and in vivo mutagenic activity of honey-sweetened cashew apple nectar (HSCAN), a beverage produced from the cashew pseudo-fruit (Anacardium occidentale L.) and of its constituents were assessed. Analytical procedures were carried out to investigate the honey used in the HSCAN preparation, and the results observed are in accordance with Brazilian legal regulations, except for diastase number. HSCAN and pulp were investigated for ascorbic acid, carotenoid, anthocyanin and total phenolic contents, and both showed high acid ascorbic concentrations. Antioxidant capacity using 2,2-diphenyl-1-picrylhydrazyl radical (DPPH) and/or ß-carotene/linoleic acid systems were applied and demonstrated a weak antioxidant capacity of honey and HSCAN, but cashew apple pulp demonstrated high antioxidant capacity. A weakly positive mutagenic effect of cashew pulp 20% was observed using the somatic mutation and recombination test (SMART) in Drosophila melanogaster only in the high-bioactivation (HB) cross. On the contrary, HSCAN was not mutagenic in both standard and high bioactivation crosses. HSCAN exhibited slight antioxidant activity, which could be associated with the high amount of ascorbic acid found in the samples evaluated. The beverage prepared did not induce DNA damage in somatic cells of D. melanogaster, which means that it is neither mutagenic nor recombinagenic in this test system.

Effect of tumor necrosis factor-α on the intracellular Ca(2+) homeostasis in human sperm.

PROBLEM: Inflammation and genital infections promote the increase in leukocytes, pro-inflammatory cytokines, and oxygen reactive species, impairing sperm functions such as motility, capacitation, and acrosome reaction. All these functions are primarily regulated by cytoplasmic concentration of Ca(2+) ([Ca(2+) ]cyto ). This study evaluated the effect of tumor necrosis factor (TNF)-α on the [Ca(2+) ]cyto and its regulation in human sperm. METHOD OF STUDY: Sperm loaded with fura-2 were incubated with or without TNF-α (0-500 pg/mL) from 0 to 120 min. After incubation, the basal [Ca(2+) ]cyto and membrane permeability to Ca(2+) were evaluated by spectrofluorometry, before and after Ca(2+) addition to the extracellular medium. RESULTS: Without TNF-α, the addition of Ca(2+) promotes an transitory increase in [Ca(2+) ]cyto in the spermatozoa, that returns in a few minutes to a basal level, indicating calcium regulation activation. TNF-α decreases the Ca(2+) permeation and increases the basal level of [Ca(2+) ]cyto after a Ca(2+) pulse (P < 0.04); affecting calcium regulation in a way that is time and concentration dependent. TNF-α effect was partially prevented by the addition of an antioxidant (butylated hydroxytoluene) (P < 0.03). CONCLUSION: Tumor necrosis factor-α decreases membrane permeability to Ca(2+) and affects Ca(2+) regulation in sperm cells in vitro, probably via lipid peroxidation, which may explain the decrease in sperm fertilizing capacity during inflammatory and infectious processes.

Rational use of antioxidants in solid oral pharmaceutical preparations

Antioxidants are currently used as efficient excipients that delay or inhibit the oxidation process of molecules. Excipients are often associated with adverse reactions. Stability studies can guide the search for solutions that minimize or delay the processes of degradation. The ability to predict oxidation reactions in different drugs is important. Methods: This study was conducted to assess the rational use of butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), sodium metabisulfite (SMB), propyl gallate (PG) and cysteine (CYS) in tablet formulations of simvastatin and ketoconazole. These antioxidants were evaluated according to stability parameters and the relationship between efficiency of the antioxidant and chemical structure of the drugs. Results were compared with DPPH tests and computational simulations. BHT was most efficient regarding simvastatin stability, and the most effective BHT concentrations for maintaining stability were 0.5 and 0.1%. In relation to ketoconazole, SMB was most efficient for maintaining content and dissolution profile. The evaluation by DPPH showed that the largest percentage of absorbance reduction was observed for PG, while SMB proved most efficient and had lower consumption of DPPH. The same pattern was observed, albeit with lower efficiency, for the other lipophilic antioxidants such as BHT and BHA. The results of the molecular modeling study demonstrated that electronic properties obtained were correlated with antioxidant activity in solution, being useful for the rational development of liquid pharmaceutical formulations but not for solid oral formulations. This study demonstrated the importance of considering stability parameters and molecular modeling to elucidate the chemical phenomena involved in antioxidant activity, being useful for the rational use of antioxidants in the development of pharmaceutical formulations.

Atualmente, antioxidantes são usados como excipientes eficientes, que retardam ou inibem o processo de oxidação de moléculas. Excipientes são frequentemente associados a efeitos adversos. Estudos de estabilidade podem ajudar na busca por possíveis soluções para minimizar ou retardar os processos de degradação. A habilidade de prever as reações de oxidação em diferentes fármacos é importante. O estudo foi conduzido com o objetivo de avaliar o uso racional de hidroxianisol butilado (BHA), hidroxitolueno butilado (BHT), metabissulfito sódico (SMB), galato de propila (PG) e cisteína (CYS) em formulações de comprimidos de sinvastatina e cetoconazol. Eles foram avaliados por parâmetros de estabilidade e pela relação entre a eficiência dos antioxidantes e a estrutura química do fármaco. Os resultados foram comparados com testes de DPPH e simulações em computador. BHT foi mais eficiente com relação a estabilidade da sinvastatina e às concentrações mais eficientes para manutenção de estabilidade foram 0,5 e 0,1%. Com relação ao cetoconazol, SMB foi mais eficiente em manter o conteúdo e o perfil de dissolução. A avaliação por DPPH mostrou que o maior percentual de redução de absorção foi observado para PG, enquanto que SMB mostrou ser mais eficiente e consumir menos DPPH. A mesma tendência foi observada com menos eficiência em todos os outros antioxidantes lipofílicos como o BHT e BHA. Os resultados do estudo de modelagem molecular demonstraram que as propriedades eletrônicas obtidas podem ser correlacionadas com a atividade antioxidante em solução, sendo útil para o desenvolvimento racional de formulações farmacêuticas líquidas, mas não para formulações sólidas orais. Este estudo demonstrou a importância de considerar parâmetros de estabilidade e modelagem molecular para elucidar os fenômenos químicos envolvidos na atividade antioxidante, sendo úteis para o uso racional de antioxidantes no desenvolvimento de formulações farmacêuticas.

Avaliação da estabilidade e atividade antioxidante de uma emulsão base não-iônica contendo resveratrol / Evaluation of antioxidant activity and stability of an emulsion base containing non-ionic resveratrol

Vários são os fatores que podem ocasionar a instabilidade de uma emulsão, destacando-se a oxidação, reação prevenida pelo emprego de antioxidantes. O butil-hidróxi-tolueno (BHT) tem sido um dos antioxidantes sintéticos mais utilizados em formulações cosméticas, porém, a busca da indústria farmacêutica e cosmética pelo emprego de produtos de origem natural tem sido cada vez maior. Visto isso, o objetivo do presente trabalho foi a incorporação do resveratrol, um composto fenólico encontrado principalmente em uvas bem como em vinhos tintos, em uma emulsão base não-iônica para avaliação do perfil de estabilidade e atividade antioxidante em comparação a uma emulsão base não-iônica contendo o BHT. O perfil de estabilidade foi analisado pela observação das características organolépticas, determinação do pH e espalhabilidade, e atividade antioxidante através do teste com o radical livre 2,2-difenil-1-picrilhidrazila (DPPH). Em relação à estabilidade, a altas temperaturas, a emulsão contendo BHT mostrou-se superior à emulsão contendo resveratrol. Pela análise da atividade antioxidante, o resveratrol tanto na sua forma de extrato seco, como quando incorporado na emulsão, demonstrou significativa superioridade em relação ao BHT, podendo ser sua utilização uma alternativa viável em preparações cosméticas, devido ao seu grande potencial antioxidante.

There are several factors that can lead to the instability of an emulsion, highlighting the oxidation, a reaction prevented by the use of antioxidants. The butylated hydroxytoluene (BHT) has been one of the most used synthetic antioxidants in cosmetic formulations; however, pharmaceutical and cosmetic industries have shown considerable interest regarding the search for the use of natural products. Based on this, the objective of this work was the incorporation of resveratrol, a natural phenolic compound found mainly in grapes as well as in red wines, into a non-ionic emulsion basis for assessing the profile of stability and antioxidant activity, as compared with a non-ionic basis emulsion containing BHT. The profile of stability was examined by the observation of the organoleptic characteristics, determination of pH and spreadability, and the antioxidant activity through the Radical Scavenging DPPH test. The results showed that the emulsion containing BHT was more stable than the emulsion containing resveratrol, when high temperature was used. For the analysis of the antioxidant activity, the resveratrol, in both forms of incorporation, showed significant antioxidant activity in comparison to BHT, suggesting that resveratrol may be a viable antioxidant alternative to be used into cosmetic preparations.