共查询到18条相似文献，搜索用时 187 毫秒
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以吴茱萸为试材,在单因素试验的基础上,通过正交实验对吴茱萸中多酚的酶法提取工艺进行了优化,采用清除DPPH·法评价了吴茱萸多酚的抗氧化活性,利用滤纸片法研究了吴茱萸多酚的抑菌活性。结果表明:吴茱萸中多酚酶法提取的最佳工艺为提取温度60℃、提取时间2.5h、纤维素酶酶浓度0.25mg·mL~(-1)、pH 4.0。在此工艺条件下,吴茱萸多酚提取率为5.58%。吴茱萸多酚清除DPPH·的能力弱于维生素C,但也具有一定的抗氧化活性。吴茱萸多酚对大肠杆菌、枯草芽孢杆菌和金黄色葡萄球菌均具有抑制作用,抑制作用大小顺序为大肠杆菌枯草芽孢杆菌金黄色葡萄球菌。吴茱萸多酚具有作为天然抗氧化剂和食品防腐剂的应用前景,值得进一步研究开发。 相似文献
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红树莓色素提取及稳定性研究 总被引：2，自引：0，他引：2
以红树莓浆果为原料,采用超声波法对红树莓果实中的色素进行提取及稳定性研究。结果表明:红树莓色素最大吸收波为510 nm,最佳提取条件为体积分数50%的乙醇溶液,按1∶10的料液比,浸提温度40℃,浸提时间30 min,提取2次。稳定性研究表明,pH对红树莓色素呈色影响较大,在低于50℃、避光条件下有较好的稳定性。红树莓色素具有一定抗氧化能力,蔗糖对色素无明显影响,VC对色素具有降解作用,Fe3+离子对红树莓色素具有保护作用,能够稳定其结构。 相似文献
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AIM: To observe the influence of polysaccharides extracted from Retinervus luffae fructus (RLF) on the differentiation of 3T3-L1 pre-adipocytes and to investigate its mechanism. METHODS: DEAE-cellulose column was used to isolate and purify RLF. The effect of RLF polysaccharides on 3T3-L1 pre-adipocyte differentiation was determined by oil red O staining. The effect of RLF on the mRNA expression of differentiation-related factors C/EBPβ, PPARγ and C/EBPα was detected by RT-qPCR. RESULTS: Two components of polysaccharides named as RLFⅠand RLFⅡ were acquired by DEAE-cellulose column and identified as polysaccharides by infrared absorption spectrum. RLFⅠsignificantly reduced the differentiation of 3T3-L1 pre-adipocytes into the adipocytes and the content of triglyceride in the cells (P < 0.05). No obvious effect of RLFⅡ was observed. Compared with control group, the mRNA levels of C/EBPβ, PPARγ and C/EBPα in RLFⅠgroup remarkably down-regulated (P < 0.05). CONCLUSION: RLFⅠsignificantly inhibits 3T3-L1 pre-adipocyte differentiation into adipocytes. The mechanism might be related to the down-regulation of differentiation-associated factors C/EBPβ, PPARγ and C/EBPα. 相似文献
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H. Shaw W. Steer R. G. Davies 《The Journal of Horticultural Science and Biotechnology》2013,88(3):190-212
Four days after placing known amounts of a 20 p.p.m. aqueous solution of 1-naphthaleneacetic acid (NAA) (14C carboxyl-labelled) on the upper surface of detached apple leaves in a greenhouse, approximately 10% of the applied radioactivity was found within the leaves, 10% was still on the surface, and 80% was lost.Apple leaves were found not to decarboxylate NAA, and the disappearance of carbon 14 from the leaf surface is attributed to the breakdown of NAA by ultraviolet radiation. The carboxyl group is lost, leaving a neutral compound, inactive in auxin tests, whose ultraviolet absorption spectrum is similar in general form to that of NAA.When a 50 p.p.m. aqueous solution of NAA containing a non-ionic wetting agent is placed on the surface of an apple leaf held in darkness at 25° C., absorption proceeds at approximately 1% per minute until the surface deposit is dry. Thereafter, absorption continues much more slowly and at a rate depending on the relative humidity of the air and the temperature.In experiments on translocation a 50 p.p.m. solution of radioactive NAA was applied to the basal leaves of fruiting spurs of Miller's Seedling. Over a period of 4 to 5 days, 17 to 28% of the carbon 14 which entered the leaves was translocated to the bourse and fruits, but between one half and three-quarters of this translocated radioactivity was in a form other than free NAA.When radioactive NAA was fed into detached apple leaves through the transpiration stream, 80 to 90% was rapidly converted into a watersoluble addition compound (I), neutral in reaction and lacking auxin activity. Over the course of several days this compound was gradually replaced by a second addition compound (II), which is acidic in nature. Compound II built up more rapidly in Cox’s Orange Pippin than in Bramley’s Seedling.The possible significance of these results is discussed, particularly in relation to the erratic performance of NAA in the field when it is used for the control of fruit drop or as a fruit-thinning agent. 1-NAPHTHALENEACETIC ACID (NAA) is a growth regulator employed in fruit-growing practice for reducing the pre-harvest drop of apples and pears, and as a fruit-thinning agent for apples. One of the chief disadvantages associated with the use of this compound is the variability in response shown by different varieties of apple, and by the same variety when treated under different conditions or in different seasons. These erratic responses make it difficult to predict the results of any particular application of NAA and offer a serious limitation to its use, particularly as a fruitthinning agent.The aim of the experiments described in this paper was to obtain quantitative data relating to the behaviour of NAA when it is applied in aqueous solution to the surface of an apple leaf. By using NAA labelled with carbon 14 in the carboxyl group, the penetration of this compound into the leaf, its translocation from the spur leaves to the bourse, and its metabolism within the tree were studied. Attention was also devoted to the destruction of NAA by ultraviolet radiation, a discovery that was made during the course of the investigation and which, like the other factors studied, was thought to have a bearing on the variable performance of NAA in the field. 相似文献
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香菇多糖提取工艺的比较研究 总被引：2，自引：0，他引：2
比较研究了超临界CO2辅助提取法和传统热水提取法2种工艺对香菇多糖提取效果的影响.试验结果表明,超临界CO2萃取的最佳工艺为:萃取压力10 Mpa,萃取温度40%,萃取时间1 h.超临界CO2萃取脱脂后,热水浸提时间为1 h.仅用了传统方法热水浸提时间的1/5,香菇多糖提取率为6.87%,比传统热水浸提法提高3.16%,所得产品紫外吸收光谱显示,产品杂质含量少,红外光谱显示结构与直接热水浸提法一致.采用超临界CO2辅助提取后,香菇多糖的提取率和质量显著提高. 相似文献
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AIM: To study the preparation, drug release, cell absorption and anti-lung cancer efficacy of magnetic nanoscale carrier with camptothecin (MNC-Camp). METHODS: The drug release ability of MNC-Camp was detected by ultraviolet spectrophotometric method. Absorption of magnetic nanoparticles by A549 cells was measured by pullulan staining method. The growth inhibition ability of Camp and MNC-Camp on the A549 cells and white blood cells was analyzed by MTT assay. The metastasis ability of A549 cells treated with Camp and MNC-Cmap was evaluated by cell invasion method. The activity of apoptosis protein caspase-3 was detected by ELISA. RESULTS: A549 cells had a good absorption ability on MNC, and the drug release of MNC-Camp increased with time increasing. Compared with MNC group, Camp and MNC-Camp induced the apoptosis of A549 cells, and the half inhibition concentration (IC50) were (35.14±3.21) and (7.16±2.54) mg/L, respectively.Camp and MNC-Camp also decreased the A549 cell transfer number and increased the activity of apoptosis protein caspase-3. All the effects of MNC-Camp were obviously significant than those of free Camp (P<0.05). CONCLUSION: MNC-Camp has a better inhibitory effect on the growth of A549 cells than free Camp, and finally plays an important role in anti-lung cancer effect. 相似文献
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Palitha Weerakkody Jenny Jobling María Magdalena Vergara Infante Gordon Rogers 《Scientia Horticulturae》2010
Consumer interest in pomegranate fruit (Punica granatum L.) is increasing in Australia as a result of its unique external and internal qualities. This work looked at the effect of applying sunscreen treatments to pomegranate fruit on the degree of sunburn damage and the effect of maturity and sunburn on the internal antioxidant concentration of the juice. The pomegranates, cultivar ‘Wonderful’ were grown in Condobolin, New South Wales, Australia. 相似文献
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苹果顶芽中内源激素动态与成花关系研究 总被引：9，自引：0，他引：9
用环切处理后的16年生金冠苹果树的顶芽甲醇提取物进行IAA、GA和ABA类物质的分离、纯化和鉴定。结果发现,5～7月IAA、GA类物质含量下降、ABA上升。环切后10天三种激素含量依次为对照的66％、43％和230％。环切后10～45天三种激素含量保持与对照有稳定的显著性差异(IAA、GA低于对照,ABA高于对照)。因此认为在花芽生理分化过程中,IAA和GA的低含量与ABA的较高含量对成花有促进作用;反之,则抑制成花。环切促进成花的原初过程或诱导因子是内源激素及其平衡状态的改变。 相似文献