共查询到18条相似文献,搜索用时 62 毫秒
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《现代农药》2013,(5)
探索荆条的抑菌活性,为综合开发利用提供科学依据。采用生长速率法测定了荆条花和叶的乙醇提取物以及各萃取物对植物病原真菌的抑制作用。结果表明:荆条花乙醇提取物的抑菌活性好于叶。当供试质量浓度为5.0 g/L时,花的乙醇提取物对苹果腐烂病菌、白菜黑斑病菌、番茄早疫病菌和棉花枯萎病菌的抑菌率分别为87.72%、77.32%、72.69%和71.37%。荆条花乙醇提取物不同溶剂萃取物中,石油醚和乙酸乙酯的抑菌活性较高。石油醚萃取物和乙酸乙酯萃取物对苹果腐烂病菌的EC50值分别为0.32 g/L和0.23 g/L;石油醚萃取物和乙酸乙酯萃取物对白菜黑斑病菌的EC50值分别为0.45 g/L和0.20 g/L。石油醚萃取物是进一步研究的重点。 相似文献
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蜂胶是一种具有芳香气味的固体胶状物,具有抗菌消炎、抗病毒、抗肿瘤、促进组织再生、降血糖、调节血脂、抗氧化等药理作用。应用电导法对蜂胶酶催化反应动力学进行研究,结果发现,在蜂胶一酶体系中,无振荡现象;在蜂胶-酶-NaCl体系内,电导率急剧升高,只出现了3个比较明显的波动峰,积累期较长,大约为10~20min,积累期过后,电导率迅速升高又迅速降低,40min后波动平缓;在蜂胶-酶-KCl体系内,反应迅速,振荡期大约为20min,30min后波动缓慢直至平台反应终止。实验证明酶催化蜂胶的反应是一个振荡反应,符合人体对食物的吸收规律。NaCl和KCl对反应的振荡有激活作用。 相似文献
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硝酸酯[季戊四三硝酸酯(PETN)和硝化棉(NC)]在加热期间的化学发光(CL)是在惰性气体中,温度为40~90℃的条件下测定的。结果表明,从凝固相以稳态方式发射弱光。此新发现意味着硝酸酯的热分解伴随有一些氧化反应。CL的光谱分析表明,发光物质首先是可发光的含羰基的三联产物和单个的氧。用阿累尼乌斯定律表述所观察到的PETN和NC的低温CL现象,产生的活化能为63kJ/mol(15kcal/mol)。对CL的动态分析表明:硝酸酯键(RO-NO_2)的初级产物的氧化反应所产生的过氧基原子团,在CL的一系列原子团反应中起着主要作用。 相似文献
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口腔疾病是影响人体健康的常见疾病,大多是由于口腔中的致病菌引起的。通过测定超临界CO2萃取的蜂胶提取物对4种口腔常见致病菌的最小抑菌浓度,证实其具有良好的抑菌性能。将其应用于牙膏,对牙膏作抑菌环试验。结果显示,该牙膏与空白牙膏相比,抑菌效果有显著性差异,与阳性对照牙膏相比,抑菌效果相当,说明该牙膏具有良好的抑菌能力。 相似文献
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Vessela D. Kortenska Milena P. Velikova Nedyalka V. Yanishlieva Iskra R. Totzeva Vassya S. Bankova Maria C. Marcucci 《European Journal of Lipid Science and Technology》2002,104(1):19-28
The effects of seven (prenyl‐ and methoxy‐) derivatives of cinnamic acid (0.1 mM) on the kinetics of lipid (sunflower oil triacylglycerols, TGSO) bulk phase oxidation at 80 °C have been compared. Synthesis of prenyl cinnamic acid derivatives: 3‐prenyl‐4‐hydroxy‐cinnamic acid (PHC), 3,5‐diprenyl‐4‐hydroxy‐cinnamic acid (DPHC), 2,2‐di‐methyl‐6‐carboxy‐ethenyl‐2H‐benzopyran (DMCB), 2,2‐dimethyl‐6‐carboxy‐ethenyl‐8‐prenyl‐2H‐benzopyran (DCEPB) present in Brazilian propolis has been performed. The monoprenyl derivative (PHC) has been found to exert a higher antioxidant activity as compared to the diprenyl derivative (DPHC). However, cinnamic acid derivatives DMCB and DCEPB have caused no change in the kinetics of TGSO oxidation. The results obtained have been compared with those on related compounds containing a cinnamic acid moiety as a structural feature, such as 4‐hydroxy‐cinnamic (p‐coumaric), 3‐methoxy‐4‐hydroxy‐cinnamic (ferulic) and 3,5‐dimethoxy‐4‐hydroxy‐cinnamic (sinapic) acids, as well as with data on butylated hydroxytoluene (BHT) and α‐tocopherol (αToc). PHC has shown a stronger antioxidant efficiency than BHT, p‐coumaric and ferulic acid, but a weaker antioxidant efficiency than α‐Toc and sinapic acid. The observed antioxidant effect of DPHC was stronger than that of p‐coumaric and ferulic acids and weaker than that of α‐Toc, BHT and sinapic acid. 相似文献
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本文综合运用正相硅胶柱层析、反相柱层析、Sephadex LH-20凝胶柱层析以及高效液相等色谱分离技术,对番荔枝科(Annonaceae)皂帽花属(Dasymaschalon)植物喙果皂帽花(Dasymaschalon rostratum)茎的化学成分进行系统分离与纯化。结合理化性质和多种现代波谱技术,并通过与文献对照,鉴定了从喙果皂帽花75%乙醇提取物的石油醚和乙酸乙酯萃取部位中分离得到11个化合物,分别为香草酸(1),methyl3,4-dihydroxybenzoate(2),香草酸甲酯(3),methyl syringate(4),syringic acid(5),4-羟基苯甲酸(6),3,4,5-trimethoxyphenol(7),3,4-dihydroxybenzoic acid ethyl ether(8),(R)3-hydroxy-3-phenylpropionate(9),3-phenylpropionic acid(10),benzyl 3-methoxybenzoate(11)。化合物9~11为首次从皂帽花属中分离得到,所有化合物均为首次从喙果皂帽花中分离得到。 相似文献
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综合运用硅胶柱层析、ODS柱层析、Sephadex LH-20凝胶柱层析以及制备高效液相等色谱分离技术,对夹竹桃科山橙属植物山橙(Melodinus suaveolens)枝叶的化学成分进行系统分离与纯化。结合理化性质和现代波谱技术,并通过与文献对照,从山橙枝叶90%乙醇提取物的石油醚萃取部位中分离得到10个化合物,分别鉴定为tabersonine(1)、scandine(2)、venalstonine(3)、venalstonidine(4)、pachysiphine(5)、scandine Nb-oxide(6)、科罗索酸(7)、乌发醇(8)、伞形花内酯(9)和6-羧基-伞形花内酯(10)。化合物7~10为首次从山橙中分离得到。 相似文献
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采用硅胶柱层析、ODS柱色谱法、Sephadex LH-20凝胶柱层析以及制备HPLC等色谱分离技术,对钩枝藤科钩枝藤属植物钩枝藤(Ancistrocladus tectorius)枝叶的化学成分进行系统分离与纯化。结合理化性质和现代波谱技术,并通过与文献对照,鉴定了从白饭树枝叶90%乙醇提取物的石油醚萃取部位分离得到8个化合物中,分别鉴定为hamatine(1)、ancistrocline(2)、ancistrocladine(3)、ancistrotectorine(4)、木犀草素(5)、鼠李素(6)、7-甲氧基香豆素(7)和东莨菪内酯(8)。化合物5~8为首次从钩枝藤属植物中分离得到。 相似文献
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Xesús Feás Lazaro Pacheco Antonio Iglesias Leticia M. Estevinho 《International journal of molecular sciences》2014,15(7):12243-12257
The present study aimed to determine the effectiveness of propolis in reducing the microbial load in ready-to-eat (RTE) and fresh whole head (FWH) lettuces (Lactuca sativa L.) type Batavia. Two sanitizing solutions were employed: sodium hypochlorite (SH) and propolis (PS), during 15 and 30 min. Tap water (TW) was used as a control. Regarding the mean reduction on aerobic mesophiles, psychrotrophic and fecal coliforms, the SH and PS treatments showed the same pattern of variation. In all cases, PS was slightly more effective in the microbiological reduction in comparison with commercial SH. Reductions between two and three log cycles were obtained with PS on aerobic mesophiles and psychrotrophic counts. The information obtained in the present study can be used to evaluate the potential use of propolis as product for sanitizing other vegetables and for developing other food preservation technologies, with impact on human health. 相似文献