沙棘叶子提取物对白化病白鼠由铬诱导氧化胁迫的抗氧化活性评估

本研究报道沙棘(胡颓子科)对雄性白化病白鼠由铬诱导氧化胁迫的抗氧化活性。氧化胁迫通过对小白鼠进行强制性喂养30 d,以浓度为30 m g/kg的铬相对体重比例的重铬酸钾盐实现。铬促使体重下降,而却明显增加了器官与体重比例。铬处理明显减少了谷胱甘肽的降低,增加了丙二醛和肌氨酸磷酸激酶的水平;而且它还加强了血清中谷氨酸草酰乙酸转移酶和谷氨酸丙酮酸转移酶的浓度。用不同剂量的沙棘叶子提取物(乙醇提取)对保护铬元素诱导的氧化胁迫进行了评估,结果表明叶子提取物在浓度为100到250 m g/kg铬与体重比的情况下可以明显保护动物避免由铬所诱导的氧化伤害。     

Chemopreventive efficacy of lycopene on 7,12-dimethylbenz[a]anthracene-induced hamster buccal pouch carcinogenesis

The chemopreventive efficacy of lycopene on 7,12-dimethylbenz[a]anthracene (DMBA)-induced hamster buccal pouch (HBP) carcinogenesis was examined using lipid peroxidation, reduced glutathione (GSH), glutathione peroxidase (GPx), glutathione S-transferase (GST) and glutathione reductase (GR) as biomarkers of chemoprevention. Twenty four male Syrian hamsters were divided into four groups of six animals each. The right buccal pouches of the animals in group 1 were painted with a 0.5% solution of DMBA in liquid paraffin three times a week. The animals in group 2 were painted with DMBA as in group 1 and in addition received 2.5 mg/kg body weight lycopene orally three times a week on days alternate to DMBA application. Group 3 animals received lycopene as in group 2. Animals in group 4 received neither DMBA nor lycopene and served as control. The hamsters were killed after an experimental period of 14 weeks. Biochemical measurements were carried out in tumour and normal tissues. All hamsters painted with DMBA alone for 14 weeks developed well-differentiated squamous cell carcinomas. Diminished lipid peroxidation in the oral tumour tissue was accompanied by a significant increase in the levels of GSH, GPx, GST and GR. Administration of lycopene significantly suppressed DMBA-induced oral carcinogenesis as revealed by the absence of carcinomas. The results of the present study suggest that lycopene may exert its chemopreventive effects by modulating lipid peroxidation and enhancing the activities of the enzymes in the glutathione redox cycle.     

Influencing in vitro clonal propagation of Chonemorpha fragrans(moon) Alston by culture media strength,plant growth regulators,carbon source and photo periodic incubation

Chonemorpha fragrans is an endangered medicinal woody climber,regarded among alternative plant sources of camptothecin.Camptothecin is a monoterpene indole anti-cancer alkaloid with annual trade value of over three billion U.S.dollars in the recent,and is used in the production of its analog drugs approved for the chemotherapy of cancer of varied types.Effects of plant growth regulators,culture media strength and photoperi-odic duration on the micropropagation ef ciency of C.fragrans from nodal segment explants were studied on Murashige and Skoog(MS)medium amended with Thidiazuron(TDZ),Benzylaminopurine(BAP)or Kinetin(Kin).Thidiazuron was more ef cient over BAP and Kin when half basal MS medium was used over full or quarter strength.Results of carbon source experiment showed sucrose as the most effective over glucose,fructose,and maltose in the clonal production.Studies on the photope-riodic incubation duration showed 12 h as the best light period and sub or supra-optimal resulted in the production of abnormal and albino micro shoots.Experimental results on the evaluation of physiological,biochemical parameters showed the role of pigment molecules and antioxidant systems in the production of albino micro shoots.     

Effect of α tocopherol and selenium on antioxidant status, lipid peroxidation and hepatopathy induced by malathion in chicks

The objective of the present study was to investigate the role of α tocopherol and selenium on malathion induced hepatic damage, and antioxidant defense in chicks. The chicks were divided into three groups. First group received malathion 10 mg/kg BW, orally for 60 days, the second group received the same dose of malathion but was supplemented with α tocopherol and selenium for 60 days and the third group served as the control. A compromised antioxidant capacity as evidenced by increased levels of erythrocytic lipid peroxidation and decreased concentration of vitamin E and decreased activity of glutathione peroxidase was observed in chicks following the administration of malathion. An improved antioxidant status was observed in chicks of second group with α tocopherol and selenium supplementation including higher concentration of vitamin E, increased activity of glutathione peroxidase and lower levels of lipid peroxidation. Histopathological studies of liver in the chicks which received malathion exhibited, moderate to severe degenerative and necrotic changes in the hepatocytes. The correlation of decreased antioxidant status of chicks with degenerative changes in liver suggests that lipid peroxidation may be one of the important mechanism in the chronic toxicity of malathion. The results indicate that α tocopherol and selenium were effective in partially alleviating degenerative changes induced by malathion in the liver of chicks by attenuating processes leading to lipid peroxidation.     

Effectiveness of potassium in mitigating the salt-induced oxidative stress in contrasting tomato genotypes

To check the efficacy of potassium in alleviating oxidative stress under salt stress, salt-tolerant (Indent-1) and salt-sensitive (Red Ball) tomato (Lycopersicon esculentum Mill.) genotypes were exposed to three levels of sodium chloride (NaCl) (0, 75, 150 mM) and two levels of potassium (4.5 and 9 mM) in solution and foliar form. Thirty days of treatments revealed that increasing NaCl stress increased lipid peroxidation (malondialdehyde, MDA) and correspondingly the activity of antioxidant enzymes (superoxide dismutase, SOD; catalase, CAT; and glutathione reductase GR) in both genotypes. However, higher potassium (K) level in solution or foliar spray during the salt-induced stress decreased MDA and antioxidant activity and increased the growth in salt-tolerant genotype than in the salt-sensitive genotype. Decrease in MDA concentration, activity of antioxidant enzymes, and increase in the growth of tomato plants by the application of potassium under salt stress suggest that potassium is an effective ameliorating agent against salt-induced oxidative damage.     

Effect of Green Tea and Vitamin E Combination in Isoproterenol Induced Myocardial Infarction in Rats

The present study was aimed to investigate the combined effects of green tea and vitamin E on heart weight, body weight, serum marker enzymes, lipid peroxidation, endogenous antioxidants and membrane bound ATPases in isoproterenol (ISO)-induced myocardial infarction in rats. Adult male albino rats, treated with ISO (200 mg/kg, s.c.) for 2 days at an interval of 24 h caused a significant (P < 0.05) elevation of heart weight, serum marker enzymes, lipid peroxidation and Ca⁺² ATPase level whereas there was a significant (P < 0.05) decrease in body weight, endogenous antioxidants, Na⁺/ K⁺ ATPase and Mg⁺² ATPase levels. Administration of green tea (100 mg/kg/day, p.o.) and vitamin E (100 mg/kg/day, p.o.) together for 30 consecutive days and challenged with ISO on the day 29th and 30th, showed a significant (P < 0.05) decrease in heart weight, serum marker enzymes, lipid peroxidation, Ca⁺² ATPase and a significant increase in the body weight, endogenous antioxidants, Na⁺/K⁺ ATPase and Mg⁺² ATPase when compared with ISO treated group and green tea or vitamin E alone treated groups. These findings indicate the synergistic protective effect of green tea and vitamin E during ISO induced myocardial infarction in rats.     

Contribution of low molecular weight antioxidants to the antioxidant screen of germinated soybean seeds

Soybean seed of the Mazovia variety (Glycine max) were germinated in the dark at a constant temperature of 25°C up to 168 h (24 h × 7). Changes in content of low molecular weight antioxidants (LMWA) in the course of germination were studied. The analyzed compounds were: total phenolics, soluble proteins, tocopherols (-T, -T, -T, -T), reduced and oxidized glutathione, L-ascorbic acid and L-dehydroascorbic acid. The changes in total antioxidant status (TAS) and the peroxyl radical-trapping capacity (PRTC) of the processed seeds were measured and compared to those of the raw seeds. On the basis of data obtained, the contribution of LMWA to the TAS of raw and germinated soybean seeds was calculated. The results showed a very high molar percentage contribution of phenolic compounds (49.7%) in opposition to glutathione (7.0%), tocopherols (4.0%) and soluble protein (5.7%) to the total TAS of raw soybean seeds. The germination process led to the increased contribution of phenolic compounds (67.7%), soluble proteins (9.3%) and ascorbic acid (4.4%) to the total TAS of germinated seeds and as a result, a decrease in the antioxidant gap was observed compared to the total TAS of raw soybean seeds. This study showed that the contribution of experimentally obtained total PRTC to the total TAS of raw and germinated soybean seeds after seven days ofthe process was 48% and 25.2%, respectively. The PRTC results were comparable to those obtained in TAS only when calculation was done by multiple mean values for content of investigated compounds and their relative potency with respect to Trolox. The PRTC values obtained in this manner were higher than those obtained experimentally indicating that high molecular weight antioxidants as well as are able to quench peroxyl radicals as well as low molecular weight antioxidants. Therefore, calculation of PRTC is a more accurate method that eliminates the puzzling question of unidentified antioxidants shown as the antioxidant gap in the TAS assay.     

植物抗氧化性的主要活性成分研究

介绍了与抗氧化活性相关的植物体内黄酮类及酚类化合物,并归纳了常见的抗氧化能力测定方法(清除羟自由基能力的测定、抑制超氧阴离子自由基的测定和FRAP法),为植物抗氧化物质的进一步研究提供了参考。     

Breeding Oilseed Crops for Improved Oil Quality

Abstract

Vegetable oils are one of the most valuable commodities in world trade. They are subject to specific quality requirements, both for food and non-food uses, there being a continuous demand for new oil types. Thus, plant breeders have made great efforts over the past four decades to develop those quality features demanded by the industry, mainly related to the fatty acid composition of the seed oil. Initially, breeders had to focus on the natural variation occurring within each oilseed crop and closely related species. From the 1970s onwards, the induction of mutations by treatment of seeds with mutagenizing agents was revealed as an effective system for modifying the fatty acid profile. In fact, mutagenesis has proved to be one of the most successful approaches for creating novel oil types. Nowadays, breeding for improved seed oil quality is in a transitional stage, both from a conceptual and a methodological point of view. First, the concept of oil quality is changing. It is not only defined by its fatty acid composition but also by other parameters, the most important being the triacylglycerol profile and the tocopherol content and composition. Second, molecular techniques for gene identification and manipulation are opening up new possibilities, much more powerful and less random than the traditional ones, for the modification of quality traits. In this review, we aim to offer an overview of seed oil quality as well as its genetic improvement by traditional and biotechnological means.     

速冻水饺猪肉馅品质的变化与控制

[目的]研究速冻水饺的肉馅随冻藏时间的延长,其品质变化的情况,以及通过抗氧化剂的添加对延缓其品质下降作用的影响.[方法]通过添加不同抗氧化剂,研究速冻水饺肉馅在冻藏90d过程中肉馅脂肪氧化程度以及对内馅品质的影响.以硫代巴比妥酸值（TBARS）来衡量脂肪氧化程度,通过解冻损失、蒸煮损失以及质构（TPA）的测定,来判断肉馅的品质变化.[结果]试验表明,随着冻藏时间的延长,水饺肉馅的TBARS值不断升高,脂肪氧化不断加深,90d后丙二醛含量超过2 mg/kg,同时肉馅解冻损失、蒸煮损失都有所增加,持水性下降,硬度、弹性、粘聚性、咀嚼性整体上呈下降趋势;添加0.010％的丁基羟基茴香醚（BHA）和0.010％的二丁基羟基甲苯（BHT）,明显降低了TBARS值,分别为0.68和0.75 mg/kg,同时各项品质指标变化程度也变小,且复合添加0.005％ BHA＋0.005％ BHT效果更优,其TBARS值为0.61 mg/kg,其他指标也略优于单独使用.[结论]研究可为提升速冻水饺品质提供一定的参考依据.