不同生长期仙人掌的营养及生理活性成分分析

对米邦塔仙人掌的营养成分、活性成分分析。结果表明粗蛋白含量为0.65%~0.68%,脂肪含量为0.30%~0.31%;氨基酸总量为6.81%~7.38%,其中谷氨酸含量达1.08%~1.52%;果胶、膳食纤维分别为1.47%~1.68%和0.87%~1.22%;干样的钙含量可达5.6%,铁8.06mg/100g,锌3.30mg/100g;B族维生素丰富,其中干样VB6含量可达5.62mg/100g;单宁0.02%~0.04%;不含草酸;生理活性物质如粗多糖、多酚、黄酮类物质分别约为1.27%、0.063%、0.036%,半乳糖约占多糖中单糖总量的80%。在不同生长期,米邦塔仙人掌矿物质、果胶、纤维素的含量逐月增长,6个月生长期的有机酸、氨基氮、单宁的含量低,而黄酮、多酚的含量高,其他营养活性成分的差异较小。     

Molecular mechanisms for chemoprevention of colorectal cancer by natural dietary compounds

Colorectal cancer is one of the major causes of cancer-related mortality in both men and women worldwide. This review focuses on preventing the initiation and promotion of neoplastic growth in colorectal cancer, particularly with natural dietary compounds. Chemoprevention is defined as the use of natural dietary compounds and/or synthetic substances that can delay, prevent, or even reverse the development of adenomas, as well as the progression from adenoma to carcinoma. The molecular mechanisms of their chemopreventive action are associated with the modulation of signaling cascades, gene expressions involved in the regulation of cell proliferation, differentiation, and apoptosis and the suppression of chronic inflammation, metastasis, and angiogenesis. Here, we summarize the currently known targets and signaling pathways whereby natural dietary compounds interfere with the development of colorectal cancer, and thus providing evidence for these substances in colonic cancer chemopreventive action.     

主成分分析法在米糠品质判断中的应用

介绍了米糠中粗SiO<,2>含量的测定方法以及主成分分析方法.通过主成分分析方法分析了15个米糠样品中粗纤维(CF)、粗脂肪(EE)、粗灰分(Ash)、粗蛋白质(CP)、粗二氧化硅(粗SiO<,2>)5个理化指标,结果表明米糠中的CF、EE、粗SiO<,2>能有效判断米糠的品质变化.     

窨制对茉莉花茶抑制癌细胞增殖的影响

目的探究茉莉花茶窨制过程中茶叶主要活性成分及抑制肝癌和胃癌细胞增殖能力的变化。方法利用四极杆飞行时间液相色谱质谱联用法和高效液相色谱法、紫外分光光度法对茉莉花茶主要活性成分进行定性和定量分析;利用主成分分析方法对窨制过程的茉莉花茶样本进行分析;利用四唑盐比色法(methyl thiazolyl tetrazolim,MTT)测定茉莉花茶抑制肝癌和胃癌细胞增殖的活性。结果本研究从茉莉花茶中鉴定出8种酚酸类及其衍生物、7种儿茶素、2种原花青素二聚体和6种黄酮醇苷类化合物。茉莉花茶细毛尖在窨制花茶过程中,其含有的黄酮、总儿茶素、生物碱、咖啡碱、没食子酸、表没食子儿茶素(epigallocatechin, EGC)、没食子儿茶素没食子酸酯(gallocatechin gallate,GCG)和表儿茶素没食子酸酯(epicatechin gallate,ECG)的含量逐渐下降;茉莉花茶龙峰在窨制成花茶过程中,其总多酚、可可碱、EGC、表儿茶素(epicatechin,EC)、表没食子儿茶素没食子酸酯(epigallocatechin gallate, EGCG)、GCG和ECG的含量逐渐上升,茶碱、没食子酸、GC含量则下降。主成分分析结果显示,不同窨制次数的茉莉花茶各自聚为一类。MTT结果显示,茉莉花茶细毛尖和龙峰的水浸出物抑制肝癌细胞HepG2增殖的IC_(50)分别为264.81～272.69μg/mL和377.46～435.95μg/mL,抑制胃癌细胞细胞BGC823的IC_(50)分别为42.49～46.35μg/mL和24.85～57.57μg/mL。茉莉花茶抑制胃癌细胞增殖能力强于肝癌,细毛尖窨制后,抑制肝癌细胞增殖能力无显著变化,抑制胃癌细胞增殖能力先下降后上升;龙峰窨制后,抑制肝癌细胞增殖能力下降15.5%,抑制胃癌细胞增殖能力增强45.3%。结论本研究初步明确了茉莉花茶的抗癌功效,明晰了茉莉花茶窨制过程中的主要活性成分和抗癌功效的变化,为消费者正确认识茉莉花茶提供科学数据支撑。     

Comparative evaluation of four free radical scavengers for the inhibition of individual glycidyl ester formation in rice bran oil determined by UPLC-MS/MS

This research investigated the effect of carnosic acid (CA), tert-butyl hydroquinone (TBHQ), sesamol (SL) and L-ascorbyl palmitate (AP) on the inhibition of glycidyl esters (GEs) and oxidation parameter changes in rice bran oil (RBO) during heat processing. The electron spin resonance (ESR) analysis showed that the free radical scavenging ability of them was ranked as CA > TBHQ > SL > AP. With the addition of CA, TBHQ, SL and AP (0.6 g kg⁻¹), the GEs content was reduced significantly from 987.98 ± 8.45 to 283.87 ± 4.78, 303.21 ± 4.38, 440.52 ± 3.82 and 500.55 ± 2.99 μg kg⁻¹, respectively. All four free radical scavengers had the highest inhibitory effect on C18:2-GE, followed by C18:1-GE and C16:0-GE. Moreover, the free radical scavengers were also effective to inhibit oil oxidation. Overall, the natural-free radical scavenger may be a promising candidate to mitigate GE formation and oil oxidation due to its effectiveness and safety.     

富硒无花果提取物片急性毒性及体外肿瘤细胞生长抑制试验研究

目的 探究自制富硒无花果提取物片的急性毒性及其体外肿瘤增殖抑制和诱导凋亡作用。方法 以富硒无花果为原料自制富硒无花果提取物片。采用SD大鼠进行急性经口毒性试验。体外用细胞计数试剂盒(cell counting kit-8, CCK-8)法观察富硒无花果提取物片对4种人源性肿瘤细胞[肺腺癌A549、肝癌(hepatitis, Hep) G2、结肠癌HCT116、乳腺癌MDA-MB-231]增殖的影响, 并采用流式细胞术分析其对细胞周期的影响。结果 富硒无花果提取物片对SD大鼠急性经口LD50大于10 g/kg?bw, 为实际无毒级别。富硒无花果提取物片对HepG2、HCT116、MDA-MB-231增殖抑制作用不明显, 对A549的最高抑制率为14.15%(P＜0.05), 量效关系显著; 流式细胞术周期分析表明其对A549细胞周期无明显影响(P＞0.05), 降低HCT116S期细胞比例, 降低HepG2G0/G1的细胞数目降低, 增加S期的细胞数目(P＜0.05)。结论 富硒无花果提取物片急性经口毒性为实际无毒级别, 对肺腺癌A549具有增殖抑制作用, 能将肝癌HepG2细胞的生长周期阻滞在S期。