植物细胞培养生产黄酮类化合物研究进展

黄酮类化合物是中药的一种主要有效成分,本文综述了利用植物细胞培养方法合成黄酮类化合物的研究状况和各种环境条件对植物细胞生长和黄酮类化合物合成的影响。     

微生物合成黄酮类研究进展

黄酮类化合物是植物特有的多酚类化合物,具有抗氧化、抗炎、抗肿瘤、改善血液循环等生理功能,在保健品、化妆品和医药等方面具有广阔的应用前景。黄酮类化合物主要通过植物提取制备,受时间空间及植物种类等因素限制,且分离纯化步骤复杂,产率较低。随着合成生物学与代谢工程的发展,构建黄酮类物质的生物合成代谢途径线路,并对基因来源、基因序列、基因组合方式、菌株底盘改造等方面进行筛选和优化已取得较大成果。现已能用工程酵母和大肠杆菌等微生物合成二氢黄酮、黄酮、异黄酮、黄酮醇、花色素和黄烷酮等黄酮类化合物,在此基础上还可经甲基化酶或糖基化酶修饰,增加新的生物活性。综述了目前国内外微生物合成各类黄酮类物质的研究进展,并对将来的发展趋势进行了讨论和分析。     

植物来源药用天然产物的合成生物学研究进展

大多数药用天然产物在植物中含量低微,提取分离困难;而且这些化合物一般结构复杂,化学合成难度大,还容易造成环境污染。基于合成生物学技术获得药用天然产物具有绿色环保和可持续发展等优点。文中以药用萜类化合物人参皂苷、紫杉醇、青蒿素、丹参酮,生物碱类化合物长春新碱、吗啡以及黄酮类化合物灯盏花素为例,总结了植物来源药用萜类、生物碱类和黄酮类化合物的生物合成途径及合成生物学研究进展,介绍了药用天然产物合成生物学研究的关键技术与方法,并展望了合成生物学技术在药用天然产物研究与开发方面的应用前景。     

微生物合成黄酮糖苷类天然产物研究进展

黄酮糖苷类天然产物是植物中黄酮类化合物的主要存在形式,通过糖基化修饰,可以改变其水溶性、稳定性等,赋予其新的生物活性和功能。黄酮类化合物的糖基化修饰通常由植物源或微生物源的糖基转移酶催化,根据糖基的位置、类型和数量的不同,可形成多种类型的黄酮糖苷类产物。随着合成生物学和代谢工程的快速发展,在微生物中合成植物源黄酮糖苷类天然产物取得了重要进展。综述了糖基转移酶的聚类分析及糖基供体的途径改造,并对代谢工程优化黄酮糖苷类天然产物的微生物合成进行了分析讨论,并对其发展前景进行了展望。     

金线莲里的活性成分

正金线莲为我国传统的名贵中草药,具有多种活性成分,素有"金草"之美誉。近年5来,"金线莲热"持续不下,价格也居高不下。那么,我们就金线莲活性成分来分析其为何如此"热"。黄酮类黄酮类化合物是一类具有2-苯基色原酮结构的化合物,广泛分布于自然界中,绝大多数植物体内都含有黄酮类化合物。在植物体中,黄酮类化合物常与糖结合成苷类,只有小部分以游离态(苷元)的形式存在。植物中的黄酮类化合物对于植物本身也具有重要的意义,在植物的生长、发育、开花、结果过程中均起着重要的作用,具有抗菌防病的功效。黄酮类化合物具有多种     

蜂胶中黄酮类化合物药理作用研究进展

黄酮类化合物是广泛存在于自然植物中的次级代谢产物,具有多种保健功能。蜂胶(propolis)是蜜蜂收集不同树植物的树脂、分泌物与蜜蜂唾液混合而成的具有芳香气味的物质,含有丰富的黄酮类化合物。综述了对蜂胶中黄酮类化合物的抗肿瘤、损伤保护、降血糖、抗氧化等多种药理作用的研究进展,以期为蜂胶黄酮类化合物相关药用研究提供参考。     

植物黄酮类化合物的研究进展

植物黄酮类化合物作为一类具有较高药用价值的化合物,一直是国内外生物类和医药类研究的热门课题。随着研究的不断进展,黄酮类化合物的药用价值及其构效关系也不断被发掘,越来越多的黄酮类化合物药物制剂也相继投入临床应用。综述了近年来植物黄酮类化合物的研究进展,对其种类结构、理化性质、药理活性及分离提纯与鉴定作了较为系统的阐述。针对生产工艺中存在的主要问题,提出了相应的解决方法。展望了其在医药卫生方面的应用前景。     

植物查尔酮异构酶研究进展

黄酮类化合物属于多酚类次生代谢物,具有广泛的药用价值。查尔酮异构酶（CHI）是黄酮类代谢途径中的一个关键酶,催化分子内环化反应,使双环的查尔酮转化为有生物学活性的三环（2S）-黄烷酮。植物体内的CHI活性与类黄酮物质的合成有着密切联系,CHI转基因研究对于提高植物类黄酮含量有重要意义。简要概述了查尔酮异构酶的结构特点、催化反应机理以及CHI转基因的研究进展。     

不同植物源的黄烷酮-3-羟化酶的催化特性

[背景]黄烷酮-3-羟化酶(flavanone-3-hydroxylase,F3H)是黄酮类化合物代谢途径中的关键酶之一,不同植物来源的F3H催化特性可能存在差异,并对黄酮类化合物的生物合成产生重要影响.[目的]比较分析不同植物源F3H的酶学性质、异源催化能力差异,为今后在黄酮类化合物代谢工程中F3H的选用提供参考.[...     

黄酮类化合物促进癌细胞凋亡的分子机理研究进展

黄酮类化合物是一类低分子天然植物成分,这类化合物具有共同的母核C6-C3-C6。黄酮类化合物具有抗炎、抗氧化、抗肿瘤、改善心血管功能等生物活性。国内、外的大量研究表明,促进肿瘤细胞的凋亡是其抗肿瘤的机理之一。随着分子生物学技术的发展,黄酮类化合物诱导肿瘤细胞凋亡的分子机理也逐渐被阐明。本文简要综述国内外黄酮类化合物诱导癌细胞凋亡的分子机理研究进展。     

搅拌式生物反应器悬浮培养水母雪莲细胞的研究

应用 2L通气搅拌式生物反应器一步批式培养水母雪莲细胞。采用倾斜式搅拌桨代替透平桨 ,研究了搅拌转速、通气量和接种量对细胞生长和黄酮合成的影响 ,发现在 75r min、70 0～1000L min和 4.0～ 5.0gDCW L接种量下细胞生长和黄酮合成比较好。经过 12d培养细胞干重达 13.8gDCW L ,黄酮产量 416mg L ,黄酮含量占细胞干重的 30%。水母雪莲细胞生长及黄酮合成的进程表明 ,黄酮积累与细胞生长呈正相关。对细胞聚集体分布的研究发现 ,流变压力使细胞聚集体分裂 ,使反应器中细胞生长受到影响 ,黄酮产量较摇瓶中降低     

Cytoplasmic accumulation of flavonoids in flower petals and its relevance to yellow flower colouration

It is widely accepted that the mix of flavonoids in the cell vacuole is the source of flavonoid based petal colour, and that analysis of the petal extract reveals the nature and relative levels of vacuolar flavonoid pigments. However, it has recently been established with lisianthus flowers that some petal flavonoids can be excluded from the vacuolar mix through deposition in the cell wall or through complexation with proteins inside the vacuole, and that these flavonoids are not readily extractable. The present work demonstrates that flavonoids can also be compartmented within the cell cytoplasm. Using adaxial epidermal peels from the petals of lisianthus (Eustoma grandiflorum), Lathyrus chrysanthus and Dianthus caryophyllus, light and laser scanning confocal microscopy studies revealed a significant concentration of petal flavonoids in the cell cytoplasm of some tissues. With lisianthus, flavonoid analyses of isolated protoplasts and vacuoles were used to establish that ca 14% of petal flavonoids are located in the cytoplasm (cf. 30% in the cell wall and 56% in the vacuole). The cytoplasmic flavonoids are predominantly acylated glycosides (cf. non-acylated in the cell wall). Flavonoid aggregation on a cytoplasmic protein substrate provides a rational mechanism to account for how colourless flavonoid glycosides can produce yellow colouration in petals, and perhaps also in other plant parts. High vacuolar concentrations of such flavonoids are shown to be insufficient.     

Suppression of bacterial cell–cell signalling,biofilm formation and type III secretion system by citrus flavonoids

Aim: This study investigated the quorum sensing, biofilm and type three secretion system (TTSS) inhibitory properties of citrus flavonoids. Methods and Results: Flavonoids were tested for their ability to inhibit quorum sensing using Vibrio harveyi reporter assay. Biofilm assays were carried out in 96‐well plates. Inhibition of biofilm formation in Escherichia coli O157:H7 and V. harveyi by citrus flavonoids was measured. Furthermore, effect of naringenin on expression of V. harveyi TTSS was investigated by semi‐quantitative PCR. Differential responses for different flavonoids were observed for different cell–cell signalling systems. Among the tested flavonoids, naringenin, kaempferol, quercetin and apigenin were effective antagonists of cell–cell signalling. Furthermore, these flavonoids suppressed the biofilm formation in V. harveyi and E. coli O157:H7. In addition, naringenin altered the expression of genes encoding TTSS in V. harveyi. Conclusion: The results of the study indicate a potential modulation of bacterial cell–cell communication, E. coli O157:H7 biofilm and V. harveyi virulence, by flavonoids especially naringenin, quercetin, sinensetin and apigenin. Among the tested flavonoids, naringenin emerged as potent and possibly a nonspecific inhibitor of autoinducer‐mediated cell–cell signalling. Naringenin and other flavonoids are prominent secondary metabolites present in citrus species. Therefore, citrus, being a major source of some of these flavonoids and by virtue of widely consumed fruit, may modulate the intestinal microflora. Significance and Impact of the Study: Currently, a limited number of naturally occurring compounds have demonstrated their potential in inhibition of cell–cell communications; therefore, citrus flavonoids may be useful as lead compounds for the development of antipathogenic agents.     

Induction of PC12 cell differentiation by flavonoids is dependent upon extracellular signal-regulated kinase activation

Many of the physiological benefits attributed to flavonoids are thought to stem from their potent antioxidant and free radical scavenging properties. Recently, it was shown that flavonoids protect nerve cells from oxidative stress by multiple mechanisms, only one of which is directly related to their antioxidant activity, suggesting that specific flavonoids may have other properties that could make them useful in the treatment of conditions that lead to nerve cell death. In particular, it was asked if any flavonoid could mimic neurotrophic proteins. To examine this possibility, we looked at the ability of flavonoids to induce nerve cell differentiation using PC12 cells. PC12 cells were treated with a variety of flavonoids to determine if there was a correlation between their neuroprotective activity and their neurite outgrowth-promoting activity. In addition, the signaling pathways required for flavonoid-induced differentiation were examined. We found that only a small subset of the flavonoids that were neuroprotective could induce neurite outgrowth by an extracellular signal-regulated kinase-dependent process. There was a strong correlation between the concentrations of the flavonoids that were neuroprotective and the concentrations that induced differentiation. These results suggest that the consumption of specific flavonoids could have further beneficial effects on nerve cells following injury, in pathological conditions or in normal aging.     

四种前体对胀果甘草细胞悬浮培养生产甘草黄酮的调控效果评价

在胀果甘草细胞悬浮体系中加入苯丙氨酸、酪氨酸、肉桂酸和乙酸钠来研究前体对甘草细胞生产甘草黄酮的影响。结果显示,4种前体在合适的浓度下对细胞的生长没有明显的抑制作用,而且均能促进细胞内甘草黄酮的生物合成,但高浓度的肉桂酸对细胞的生长有一定的抑制作用。苯丙氨酸的最佳添加浓度为20 mg/L,酪氨酸、肉桂酸、乙酸钠的最佳添加浓度都是5 mg/L。此时,均可使培养体系的甘草黄酮产量高达100 mg/L以上,其中酪氨酸的添加使得产量高达对照的1.43倍。苯丙氨酸、肉桂酸和乙酸钠3种前体的添加时间均以第10天为宜,酪氨酸添加时间以第5天为最佳。而且,在添加苯丙氨酸和乙酸钠后的第3天收获细胞,此时细胞的生物量和甘草黄酮产量最大。此外,苯丙氨酸、乙酸钠的添加可以增加黄酮合成的关键酶之一——苯丙氨酸裂解酶的活性。酪氨酸对苯丙氨酸裂解酶影响不大,而肉桂酸的添加却导致其活性显著降低。     

软枣猕猴桃总黄酮对V79细胞的辐射防护作用

目的:研究软枣猕猴桃总黄酮的辐射防护活性。方法:以V79细胞辐射损伤模型为体外验证模型,利用回流醇提法提取的软枣猕猴桃总黄酮于辐射前处理细胞,细胞经8 Gy60Coγ射线辐射后,用多功能酶标仪检测细胞的存活率,用流式细胞仪检测细胞内活性氧及细胞凋亡率的变化。结果:用50～200μg/mL的软枣猕猴桃总黄酮于辐射前给药细胞,进行24 h培育,能抑制细胞内因辐射引起的活性氧上升,从而提高细胞存活率。结论:软枣猕猴桃总黄酮能清除细胞内由辐射产生的活性氧,降低细胞凋亡率,达到保护V79细胞的效果。     

前体对水母雪莲悬浮培养细胞黄酮合成的影响

在水母雪莲（Saussurea medusa Maxim)细胞悬浮体系中加入苯丙氨酸、肉桂酸和乙酸钠3种前体。结果显示,3种前体均能促进细胞内黄酮的生物合成,但它们对细胞的生长也有一定的抑制作用。实验表明,3种前体的添加时间均以第6天为宜。苯丙氨酸的最佳添加浓度为0.05mmol/L,肉桂酸、乙酸钠的最佳添加浓度都是0.1mmol/L。3种前体中,难溶于水的肉桂酸对黄酮合成的促进作用最强,它可使培养物的黄酮产量高达1801mg/L,是对照1．98倍。苯丙氨酸、乙酸钠两种前体协同添加,比它们单独加入更能促进细胞的黄酮合成。     

Dietary flavonoids and modulation of natural killer cells: implications in malignant and viral diseases

Flavonoids are a large group of secondary plant metabolites present in the diet with numerous potentially health-beneficial biological activities. In addition to antioxidant, anti-inflammatory, cholesterol-lowering, and many other biological functions reported in the literature, flavonoids appear to inhibit cancer cell proliferation and stimulate immune function. Although the immunomodulatory potential of flavonoids has been intensively investigated, only little is known about their impact on natural killer (NK) cells. Enhancing NK cell activity, however, would have strong implications for a possible clinical use of flavonoids, especially in the treatment and prevention of diseases like cancer and viral infections. Therefore, the purpose of this review is to summarize the currently available information on NK cell modulation by flavonoids. Many of the structurally diverse flavonoids stimulate NK cell activity and have thus great potential as diet-derived immune-modulatory chemopreventive agents and may even serve as therapeutic compounds or lead structures for the development of novel drugs for the treatment of both malignant and viral diseases.     

Tapetosomes in Brassica tapetum accumulate endoplasmic reticulum-derived flavonoids and alkanes for delivery to the pollen surface

Tapetosomes are abundant organelles in tapetum cells during the active stage of pollen maturation in Brassicaceae species. They possess endoplasmic reticulum (ER)-derived vesicles and oleosin-coated lipid droplets, but their overall composition and function have not been established. In situ localization analyses of developing Brassica napus anthers revealed flavonoids present exclusively in tapetum cells, first in an ER network along with flavonoid-3'-hydroxylase and then in ER-derived tapetosomes. Flavonoids were absent in the cytosol, elaioplasts, vacuoles, and nuclei. Subcellular fractionation of developing anthers localized both flavonoids and alkanes in tapetosomes. Subtapetosome fractionation localized flavonoids in ER-derived vesicles, and alkanes and oleosins in lipid droplets. After tapetum cell death, flavonoids, alkanes, and oleosins were located on mature pollen. In the Arabidopsis thaliana mutants tt12 and tt19 devoid of a flavonoid transporter, flavonoids were present in the cytosol in reduced amounts but absent in tapetosomes and were subsequently located on mature pollen. tt4, tt12, and tt19 pollen was more susceptible than wild-type pollen to UV-B irradiation on subsequent germination. Thus, tapetosomes accumulate ER-derived flavonoids, alkanes, and oleosins for discharge to the pollen surface upon cell death. This tapetosome-originated pollen coat protects the haploidic pollen from UV light damage and water loss and aids water uptake.