反式肉桂醛与温和加热结合对复原婴幼儿牛乳中阪崎克罗诺肠杆菌的抑杀作用

研究反式肉桂醛与温和加热结合对复原婴幼儿牛乳中阪崎克罗诺肠杆菌的抑杀作用。将3 种阪崎克罗诺 肠杆菌的混合菌株（浓度约6.6（lg（CFU/mL）））接种于含有不同质量分数反式肉桂醛（0、0.1%、0.2%、0.3% 和0.4%）的复原婴幼儿牛乳样品中,将样品置于25、45、50、55 ℃培养,并在不同的时间点对样品中存活的阪崎 克罗诺肠杆菌涂布计数。为探究反式肉桂醛与温和加热结合的抑杀机制,实验利用LIVE/DEAD?细菌活性检测试 剂盒和场发射扫描电子显微镜探究细胞膜完整性及细胞形态。结果表明：0.4%的反式肉桂醛在25 ℃处理90 min、 45 ℃处理20 min、50 ℃处理10 min及55 ℃处理10 min使复原婴幼儿牛乳中阪崎克罗诺肠杆菌总数降低至检出限 以下。与反式肉桂醛及温和加热单独作用相比,反式肉桂醛结合温和加热对阪崎克罗诺肠杆菌有显著的抑杀效果 （P＜0.05）,并且随温和加热温度的升高及反式肉桂醛质量分数的增加,效果更加明显。温和加热与反式肉桂醛 结合会影响细胞膜的通透性并使细胞破碎瓦解。以上结果表明：反式肉桂醛与温和加热结合有潜力在冲调乳粉过程 中应用,从而降低阪崎克罗诺肠杆菌的感染风险。     

Construction of new iodide selective electrodes based on bis(trans-cinnamaldehyde)1,3-propanediimine(L) zinc(II) chloride [ZnLCl2] and bis(trans-cinnamaldehyde) 1,3-propanediimine(L) cadmium(II) chloride [CdLCl2]

New plasticized PVC membranes iodide selective electrodes have been prepared by incorporating bis(trans-cinnamaldehyde)1,3-propanediimine zinc(II) chloride [ZnLCl2] and bis(trans-cinnamaldehyde) 1,3-propandiimine cadmium(II) chloride [CdLCl2] on the surface of graphite disk electrodes. At optimum value of variables the proposed electrodes have selective response to iodide with respect to a number of inorganic and organic anions with near-Nernstian slopes of − 60 ± 1.9 and − 58.5 ± 1.9 mV/decade of iodide concentration over the range 1.0 × 10^− 6-1.0 × 10^− 1 M with detection limits of 4.0 × 10^− 7 and 3.0 × 10^− 7 M for the electrodes based on [ZnLCl₂] and [CdLCl₂], respectively. The electrodes based on both ionophores have response times of about (6 s), with stable reproducible response during 2 months, while their responses is independent of pH over the range 2.5-10.5. The proposed electrodes successfully have been applied for evaluation of iodide ion content in real samples with complicated matrices including water and pharmaceutical samples.     

Sub-Inhibitory Concentrations of Trans-Cinnamaldehyde Attenuate Virulence in Cronobacter sakazakii in Vitro

Cronobacter sakazakii is a foodborne pathogen, which causes a life-threatening form of meningitis, necrotizing colitis and meningoencephalitis in neonates and children. Epidemiological studies implicate dried infant formula as the principal source of C. sakazakii. In this study, we investigated the efficacy of sub-inhibitory concentrations (SIC) of trans-cinnamaldehyde (TC), an ingredient in cinnamon, for reducing C. sakazakii virulence in vitro using cell culture, microscopy and gene expression assays. TC significantly (p ≤ 0.05) suppressed C. sakazakii adhesion to and invasion of human and rat intestinal epithelial cells, and human brain microvascular endothelial cells. In addition, TC inhibited C. sakazakii survival and replication in human macrophages. We also observed that TC reduced the ability of C. sakazakii to cause cell death in rat intestinal cells, by inhibiting nitric oxide production. Results from gene expression studies revealed that TC significantly downregulated the virulence genes critical for motility, host tissue adhesion and invasion, macrophage survival, and LPS (Lipopolysaccharide) synthesis in C. sakazakii. The efficacy of TC in attenuating these major virulence factors in C. sakazakii underscores its potential use in the prevention and/or control of infection caused by this pathogen.     

Antimicrobial Effect of α- or β-Cyclodextrin Complexes with Trans-Cinnamaldehyde Against Staphylococcus aureus and Escherichia coli

Molecular inclusion or encapsulation based on cyclodextrin (CD) is the most widely used method in encapsulation technology. α- and β-CD complexes consisting of antibacterial trans-cinnamaldehyde were prepared by the molecular inclusion method. The characteristics of the complex were determined, including examination of their antimicrobial effects after the drying process. The particle sizes of the trans-cinnamaldehyde–CD complexes were observed in the range of 300 to 500 nm after production. Particle sizes of both trans-cinnamaldehyde–CD complexes were slightly increased increasing in a dose-dependent manner of trans-cinnamaldehyde. Although β-CD complexes were larger than α-CD complexes, they possessed a lower polydispersity index with a narrow size distribution. The encapsulation efficiency of trans-cinnamaldehyde–CD complexes was >90% in all formulations. Trans-cinnamaldehyde affected reduction of Staphylococcus aureus and Escherichia coli, with antibacterial activity increasing in a dose-dependent manner of trans-cinnamaldehyde concentration. In addition, β-CD complexes showed more effective antimicrobial effects compared to α-CD complexes.     

Trans-cinnamaldehyde from Cinnamomum zeylanicum bark essential oil reduces the clindamycin resistance of Clostridium difficile in vitro

ABSTRACT:  Therapy with antimicrobial drugs, such as clindamycin, that perturb the intestinal flora but fail to inhibit growth of other microorganisms can permit the proliferation of Clostridium difficile and the elaboration of exotoxin. Therefore, there has been increasing interest in the use of inhibitors of antibiotic resistance for use in combination therapy. The essential oil of Cinnamomum zeylanicum bark enhanced the bactericidal activity of clindamycin and decreased the minimum inhibitory concentration of clindamycin required for a toxicogenic strain of C. difficile . Thin-layer chromatography (TLC) analysis of the essential oil separated a fraction ( R _f = 0.54) that was the most effective at enhancing the clindamycin antimicrobial activity. Using gas liquid chromatography and known standards, the active fraction was identified as trans-cinnamaldehyde (3-phenyl-2-Propenal). Combinations of clindamycin and trans-cinnamaldehyde were tested to determine the fractional inhibitory concentration (FIC) index by conventional checkerboard titration. The FIC index for C. difficile was found to be 0.312, which confirmed the synergistic actions of clindamycin and trans-cinnamaldehyde. The presence of 20 μg/mL of trans-cinnamaldehyde decreased the MIC of clindamycin for C. difficile 16-fold, from 4.0 to 0.25 μg/mL. These results signify that low concentrations of trans-cinnamaldehyde elevate the antimicrobial action of clindamycin, suggesting a possible clinical benefit for utilizing these natural products for combination therapy against C. difficile .     

少花桂叶香气活性成分分析鉴定

对少花桂叶的香气活性成分进行分析鉴定。采用顶空固相微萃取制备样品,用两根色谱柱（极性柱DB-WAX和弱极性柱DB-5）进行气相色谱-质谱联用分析,并用DB-5柱进行直接强度法气相色谱－嗅闻分析（GC-O),基于保留指数、质谱库检索、气味特征鉴定化合物。结果:共鉴定出88种挥发性成分,含量高（>1%）的成分为芳樟醇、香豆素、δ-杜松烯、檀香萜、α-古巴烯、苯乙烯、β-檀香萜、反式肉桂醛、乙酸龙脑酯和1, 8-桉叶油素等。检测到23种化合物有气味活性,按照气味强度,对总体香气贡献大（香气强度值≥ 3）的为反式肉桂醛、芳樟醇、4-萜品醇、乙酸龙脑酯、β-檀香萜和肉桂酸乙酯,研究结果为少花桂的开发应用提供基础。     

The Influence of Electron Beam Irradiation on the Effectiveness of Trans-cinnamaldehyde-coated LDPE/Polyamide Films

ABSTRACT:  We have evaluated the effect of electron beam irradiation (up to 20 kGy) on the functional and barrier properties of trans-cinnamaldehyde-coated low-density polyethylene (LDPE)/polyamide films. Irradiation did not affect the tensile strength and toughness of the films, but the 20 kGy treatment increased the percent elongation-at-break significantly. The barrier properties were also enhanced (approximately 18.8%) when the films were exposed to 20 kGy. Addition of trans-cinnamaldehyde with 3% of polyamide coating solution (w/w) did not affect the tensile strength and barrier properties of the films, but significantly decreased the percent elongation-at-break and toughness. Films with 3% and 10% coating were used to wrap fresh-cut romaine lettuce samples to determine their antimicrobial activity. Total aerobic plate count (APC) and yeast and mold growth were determined as a function of dose (0, 0.5, and 1.0 kGy) for 14 d of storage at 4 °C. Irradiation reduced the total APC and yeast and mold counts (YMC) as dose increased. The 0.5- and 1.0-kGy treatments decreased initial APCs by 1.2- and 1.5-logs, and no YMCs were observed in the 1.0-kGy treated samples at day 0. Irradiation exposure significantly lowered APCs of lettuce samples by almost 1-log colony-forming unit (CFU)/g compared to the nonirradiated controls, though it only slightly reduced YMCs. The effectiveness of using irradiation with antimicrobial films was enhanced with increased radiation dose and trans-cinnamaldehyde concentration (3% to 10%).     

The yeast alcohol dehydrogenase catalysed conversion of cinnamaldehyde to cinnamyl alcohol

The kinetics of the conversion of trans-cinnamaldehyde to trans-cinnamyl alcohol catalysed by yeast alcohol dehydrogenase (EC 1.1.1.1) have been characterised. Reaction with the free enzyme is curtailed after a short time as a result of inactivation by the substrate. It has been shown that immobilisation of the enzyme provides substantial protection against this inactivation. Use of the immobilised enzyme in a flow-through reactor further enhanced the enzyme lifetime, creating a viable synthetic process. The product cinnamyl alcohol may be recovered by continuous solvent extraction.     

肉桂醛特异性抑制酵母细胞壁合成的作用机理

基于酿酒酵母(Saccharomyces cerevisiae)及其细胞壁合成酶缺陷突变株组成的筛选模型对肉桂醛抗真菌的作用机制进行了研究。发现肉桂醛对细胞壁合成酶基因缺陷突变株及其野生型的抑制具有显著差异,对葡聚糖合酶缺陷突变株Δfks1的最低抑制浓度MIC值为8μg/mL,比野生型低8倍,肉桂醛对几丁质合酶基因缺陷突变株CHS020和CHS003的MIC值也比野生型低4倍。肉桂醛对Δfks1生长的抑制能被山梨醇等渗溶液部分挽救,经肉桂醛处理后,Δfks1的β-葡聚糖和几丁质含量分别降低了23.48%和31.94%。研究结果表明,肉桂醛特异性抑制真菌细胞壁葡聚糖和几丁质的合成是其抑制真菌细胞生长的主要机制之一。