Anti-carcinogenic potential of Euphorbia neriifolia leaves and isolated flavonoid against N-Nitrosodiethylamine-induced renal carcinogenesis in mice.

Anti-carcinogenic potential of hydro-ethanolic extract of Euphorbia neriifolia (EN) leaves and an isolated flavonoid (ENF) was investigated against N-Nitrosodiethylamine (DENA)-induced renal carcinogenesis in mice. Experimental mice were pretreated with 150 and 400 mg/kg body wt of EN, 0.5% and 1% mg/kg body wt of butylated hydroxylanisole (BHA) as a standard antioxidant and 50 mg/kg body wt of ENF for 21 days prior to the administration of a single dose of 50 mg/kg body wt of DENA. Levels of renal markers (urea and creatinine), xenobiotic metabolic enzymes (Cyt P450 and Cyt b5), lipid peroxidation (LPO), antioxidants (SOD, CAT, GST and GSH) and other biochemical parameters — AST, ALT, ALP, total protein (TP), and total cholesterol (TC) were measured to determine the renal carcinogenesis caused by DENA. DENA administration significantly (p<0.001) decreased the body weight and increased the tissue weight. It significantly (p<0.001) enhanced the levels of Cyt P450, Cyt b5 and LPO and decreased the levels of SOD, CAT, GST and GSH content. The activities of AST, ALT and ALP and the TP content and renal markers were also significantly decreased (p<0.001), while TC level was markedly increased after DENA administration, as compared with the normal control group (p<0.001). Pretreatment with EN and ENF counteracted DENA-induced oxidative stress (LPO) and exerted its protective effects by restoring the levels of antioxidants (SOD, CAT, GST and GSH), biochemical parameters (AST, ALT, ALP, TP and TC), renal markers (urea and creatinine) and xenobiotic enzymes (Cyt P450 and Cyt b5) in renal tissue. In conclusion, the present study showed significant anti-carcinogenic potential of the hydro-ethanolic extract of E. neriifolia and ENF against DENA-induced renal carcinogenicity.

Influência do processamento, de antioxidantes e da estocagem sobre a estabilidade oxidativa lipídica do ovo / Influence of processing, antioxidants and storage on oxidative stability of egg lipids

O ovo é consumido in natura ou processado, e usado como matéria-prima em diversos produtos. A pasteurização e a atomização são os principais processamentos aplicados ao ovo. Diferentes condições de processamento, embalagem e estocagem podem afetar a estabilidade oxidativa lipídica e reduzir a proteção antioxidante natural do ovo. O uso de embalagens onde não haja contato do ovo com a luz e oxigênio, estocagem em temperaturas baixas e uso de antioxidantes podem prevenir a oxidação lipídica. Atualmente, os antioxidantes sintéticos são cada vez mais substituídos por antioxidantes naturais ou feita uma associação entre eles. O alecrim (Rosmarinus officinalis L.) e o chá verde (Camelia sinensis L) constam entre os vegetais com grande potencial antioxidante. Com base no exposto, os objetivos do trabalho foram: a) Padronizar o método do fosfomolibdênio para avaliação da capacidade antioxidante total da fração lipídica (CATL) do ovo; b) Investigar o efeito da pasteurização e da atomização do ovo no que se refere à capacidade antioxidante e à estabilidade oxidativa da fração lipídica do ovo; c) Avaliar a estabilidade oxidativa de ácidos graxos e a capacidade antioxidante do ovo integral pasteurizado atomizado, estocado a 5ºC, por 90 dias; d) Verificar por meio de teste de concentração de antioxidantes, a estabilidade oxidativa lipídica do ovo integral pasteurizado atomizado adicionado da mistura de extrato de alecrim, extrato de chá verde e BHA (butilato de hidroxianisol); e) Otimizar a concentração da mistura de extrato de alecrim, extrato de chá verde e BHA a ser adicionada ao ovo líquido integral pasteurizado, posteriormente atomizado, pelo modelo matemático proposto pela metodologia de superfície de resposta; f) Investigar o efeito da mistura otimizada de extrato de alecrim, extrato de chá verde e BHA na estabilidade oxidativa lipídica do ovo integral pasteurizado atomizado, estocado sob as temperaturas de 5°C e 25ºC, por 90 dias. O método do fosfomolidênio para medir a CATL do ovo apresentou adequação analítica, indicada pela equação de regressão (y = 13,705x + 0,0808), coeficiente de determinação (R2 = 0,9931), limite de detecção (0,005mg α-tocoferol/ mL), limite de quantificação (0,017mg α-tocoferol/ mL), coeficiente de correlação (r = 0,9965), sendo que a precisão não indicou dispersão ao redor da média. A CATL diminuiu com o progresso do processamento e o inverso foi observado quanto aos lipídios, 7-CETO (7-cetocolesterol) e TBARS (substâncias reativas ao ácido tiobarbitúrico). O ovo integral pasteurizado atomizado (OIPA) mantido sob condições de estocagem consideradas ideais permaneceu estável em relação à hidratação, a CATL e as TBARS. Pelo teste de concentração de antioxidantes, foram ensaiadas dez misturas (alecrim, chá verde e BHA) no OIPA e refletiu na sua estabilidade oxidativa lipídica, verificada pelas TBARS, CATL, CT-F (capacidade redutora pelo reativo de Folin - Ciocalteau), AGL (ácidos graxos livres) e AS-233 (substâncias absorvidas a 233 nm). Os resultados mostraram que a metodologia de superfície de resposta (RSM) foi adequada para descrever a formação dos AGL e AS-233 no OIPA, podendo serem usadas para fins preditivos. A otimização da mistura de antioxidantes baseou-se no modelo matemático obtido com as AS-233, onde foi proposto como sistema antioxidante 150ppm de BHA, 600ppm de alecrim e 300ppm de chá verde. As condições de estocagem adotadas e a adição dos antioxidantes foram efetivas para manter estável o OIPA, sendo mais efetivo quando estocado a 5°C. Concluíu-se que o método do fosfomolibdênio apresentou adequação analítica. A pasteurização não afetou os parâmetros analisados (lipídios, TBARS, CATL e 7-CETO), mas a atomização provocou diminuição significativa da CATL, e elevação dos lipídios, TBARS e 7-CETO. Foi mantida a hidratação e a estabilidade oxidativa do OIPA estocado por 90 dias a 5°C, indicando que as condições de embalagem e estocagem foram efetivas. Pelo modelo matemático proposto pela RSM foi constatado que apenas os AGL e AS-233 podem ser usados para fins preditivos, optando-se pela otimização da concentração da mistura de antioxidantes, usando apenas o modelo matemático obtido nas AS-233. Com a presença ou não de antioxidantes, o OIPA estocado a 5°C, ao longo dos 90 dias, apresentou-se mais estável quanto à hidratação e à oxidação lipídica

Egg is consumed in natura or processed and is used as raw material in various food products. The pasteurization and spray-drying processes are the main processing applied to the egg. Different processing conditions, packaging and storage can affect the lipid oxidative stability and may reduce the natural antioxidant protection of this product. The use of packages in which the egg has no contact with light and oxygen, storage at low temperatures, and the use of antioxidants can prevent lipid oxidation. Currently, synthetic antioxidants have been increasingly replaced by natural antioxidants or an association between synthetic and natural antioxidants is adopted by food companies. Rosemary (Rosmarinus officinalis L.) and green tea (Camellia sinensis L) are among the vegetables that present the highest antioxidant potential. Based on the above-mentioned considerations, the objectives of this research were: a) To standardize the method of phosphomolybdenum to evaluate the total antioxidant capacity of lipid fraction (CATL) egg; b)To investigate the effect of pasteurization and spray-drying on the antioxidant capacity and oxidative stability of the lipid fraction of egg; c) To assess the oxidative stability of fatty acids and the antioxidant capacity of whole egg subjected to pasteurization followed by spray-drying, stored at 5ºC for 90 days, d) To evaluate the by testing the concentration of antioxidants, oxidative stability of the lipid fraction of egg subjected to pasteurization and spray drying, added with a mixture of rosemary and green tea extracts and BHA (butylated hydroxyanisole); e) To optimize the concentration of the mixture composed of rosemary and green tea extracts and BHA to be added to pasteurized liquid egg (and further subjected to spray-drying) by using Response Surface Methodology; f) To investigate the effect of the addition of this optimized mixture of antioxidants on of the lipid fraction of spray-dried egg, stored at temperatures of 5 and 25°C for 90 days. The phosphomolybdenum method CATL of egg presented analytical suitability once it presented a high coefficient of determination (R2 = 0,9931), a regression equation expressed as y = 13.705 + 0.0808 x, a limit of detection of 0.005 mg α- tocopherol/mL, a limit of quantitation of 0.017 mg α-tocopherol/mL, a significant and high correlation coefficient (r = 0.9965), and the accuracy did not indicate dispersion around the mean. The CATL decreased with the progress of processing and the reverse was observed for the lipids, 7-CETO (7-ketocholesterol) and TBARS (thiobarbituric acid reactive substances). The pasteurized spray-dried egg (OIPA), which was kept under ideal storage conditions, remained stable in relation to moisture content, CATL and TBARS. In order to test the concentration of antioxidants to be added to OIPA, a total of 10 mixtures (rosemary, green tea and BHA) were assayed. The addition of antioxidants resulted in a higher oxidative stability of the lipid fraction as measured by TBARS, CATL, CT-F (reduction capacity by using the Folin-Ciocalteau reagent), AGL (free fat acids) and AS-233 (substances that absorb at 233 nm). The results showed that the response surface methodology (RSM) was adequate to describe the development of free fat acids and AS-233 in OIPA, and the RSM model proposed for AS-233 can be used for prediction purposes. The optimization of the antioxidant mixture based on the mathematical model proposed for AS-233 indicated that the mixture of 150ppm of BHA, 600ppm of rosemary extract and 300ppm of green tea extract was the best combination of antioxidants. The adopted storage conditions and the addition of antioxidants to OIPA were effective to maintain the response variables stable, and the stability was higher when OIPA was stored at 5°C. It was concluded that the method of phosphomolybdenum suitability presented analytically. The pasteurization did not affect the analyzed parameters (lipids, TBARS, CATL and 7-CETO), but the spray-drying caused a significant decrease CATL, and an increase in lipids, TBARS and 7-CETO. The hydration and the oxidative stability of OIPA remained stable for 90 days at 5°C, indicating that the packaging and storage conditions were effective. The RSM models proposed for free fat acids and AS-233 could be used for predictive purposes; however, the optimization procedure was performed taken into account only the AS-233 model. The OIPA stored at 5°C for 90 days, with or without the addition of the antioxidant mixture, was more stable in relation to hydration and lipid oxidation

Enhancement of O-dealkylation in Mouse Liver by Dietary Administrations of BHA and BHT: Studies with Isolated Perfused Livers and Hepatic Microsomes

Effects of feeding 2(3)-tert-butyl 4-hydroxyanisole (BHA) and 3, 5-di-tert-butyl 4-hydroxytoluene (BHT) on the rates of mixed function oxidation and conjugation enzyme reactions have been determined using isolated hepatic microsomal fractions and isolated perfused livers of mice. The treatments with either of the antioxidants have increased the rates of O-demethylation for p-nitroanisole and of O-deethylation for 7-ethoxycoumarin up to 2-fold, both in microsomes and in perfused liver. Analysis of the perfusate showed that the increased amounts of p-nitrophenol and 7-hydroxycoumarin produced by the elevated mixed-function oxidase activities were reflected by the increase in the amounts of glucuronide conjugates and not in the increase for the amounts of the sulfate ester conjugates. Comparison of results also indicated that in the perfused liver, the maximal rate of metabolite conjugation is limited by the maximal rates of the initial mixed function oxidase activities.

Effect of Antioxidants on the Incidence of 7, 12-dimethylbenzanthracene-induced Mammary Tumor in Rats

The inhibitory effect of selenium, vitamin E, and BHA on DMBA-induced mammary tumorigenesis in rats was investigated. Dietary vitamin E (200 IU/Kg diet) alone could not reduce the tumor incidence at 25 weeks after DMBA administration (10mg DMBA/rat) when selenium was deficient. Selenium supplementation (2ppm in drinking water) to rats fed a practical diet (0.17 ppm Se) reduced the tumor incidence to 14.3% from 75% at 27 weeks after DMBA administration. Dietary supplementation of BHA (0.75%) also reduced the incidence of DMBA-induced mammary tumor to 42.9% at 27 weeks after DMBA-treatment. Rats fed a diet deficient in both selenium and vitamin E contained significantly lower glutathione peroxidase activity and higher malondialdehyde in muscle. However, supplementation of selenium or BHA to the rats fed a practical diet did not alter the malondialdehyde content and glutathione peroxidase activities in muscle, skin and mammary gland. Dietary selenium increased the tissue selenium level. DMBA-induced mammary tumorigenesis was reduced by antioxidants tested but the anticarcinogenic effect of selenium or BHA seems to be independent of glutathione peroxi-dase activity.

Effect of p-Dimethylaminoazobenzene and 2(3)-tert-Butyl-4-hydroxyanisole on Lipid Pcroxidation, Glutathione-S-transferase, Peroxidase and Reductase in Rat Liver

An experiment was conducted in order to investigate the effect of p-dimethylaminoazobenzene (DAB) and 2(3)-tert-butyl-4-hydroxyanisole (BHA) on the lipid peroxidation and peroxide-destroying enzyme system in the rat liver. Dietary supplementation of DAB (0.06%) for three weeks caused the elevation of glutathione-S-transferase activity by 60% and glutathione reductase by 50%, but it decreased glutathione peroxidase and catalase activities significantly. Dietary supplementation of BHA (0.75%) also increased glutatione-S-transferase activity in the liver by 2 folds, and it counteracts DAB effect on the glutathione peroxidase and catalase activities. There was a marked increase in malon-dialdehyde content in the postnuclear fraction of liver by the treatment of DAB, but the addition of BHA lowered the malondialdehyde content to almost the control level. The protective effect of BHA on the lipid peroxidation induced by DAB administration at the enzyme level seems to be due to the induction of glutathione-S-transferase and the protection of glutathione peroxidase and catalase activities from being lowered by DAB administration.