In vivo treatment of acute Chlamydia pneumoniae infection with the flavonoids quercetin and luteolin and an alkyl gallate, octyl gallate, in a mouse model

Increasing evidence suggests that plant polyphenolic compounds may protect from cardiovascular diseases, which have been addressed to their antioxidative properties. In addition, these compounds have been shown to possess anti-inflammatory and anti-microbial potential. In the present study we tested the effects of two flavonoid compounds, quercetin and luteolin, and one alkyl gallate, octyl gallate, on the course of acute Chlamydia pneumoniae infection in vivo. C57BL/6J mice were treated with quercetin, luteolin or octyl gallate for 3 days prior to and 10 days after C. pneumoniae inoculation. Lung tissue was analysed for the presence of chlamydia by culture and quantitative PCR, and inflammatory responses were assessed. Luteolin was found histologically to suppress inflammation in lung tissue, the development of C. pneumoniae-specific antibodies and the presence of chlamydia in lung tissue. Octyl gallate had no significant effect on the course of infection, but quercetin increased both the inflammatory responses and the chlamydial load in the lungs. The infection and inflammation-enhancing effects of quercetin treatment may be attributable to the dose and the route of administration and should be reassessed in further studies with lower doses or with different metabolites of the compound. Contrariwise, the effects of luteolin treatment suggest this compound to have potential in decreasing the infection load and inflammatory reactions in vivo.     

The effect of quercetin on pro-apoptotic activity of cisplatin in HeLa cells

It is well known that some tumour cells are very resistant to chemotherapy-induced cell death which indicate poor prognosis for patients. Thus the aim of the present study was to investigate the effect of quercetin on pro-apoptotic activity of cisplatin in human cervix carcinoma cells (HeLa). Three variants of experiments were performed. In the first one cells were incubated with studied drugs separately for 8 and 24h. In the second, drugs were added to the culture medium simultaneously. In third cisplatin or quercetin addition was followed by subsequent quercetin or cisplatin treatment, respectively. We observed different apoptotic effects, dependent on the drug succession. Preincubation of cells with quercetin followed by cisplatin treatment appeared to be the most effective and was correlated with strong activation of caspase-3 and inhibition of both heat shock proteins (Hsp72) and multi-drug resistance proteins (MRP) levels. Our results indicate that quercetin pretreatment sensitizes HeLa cells to cisplatin-induced apoptosis in HeLa cells.     

Simultaneous determination of quercetin, kaempferol and (E)-cinnamic acid in vegetative organs of Schisandra chinensis Baill. by HPLC

A reversed-phase high-performance liquid chromatographic (RP-HPLC) separation method with UV spectrophotometric detection has been developed for the determination of major components in leaves and caulomas of Schisandra chinensis Baill. The flavonols (quercetin and kaempferol) and (E)-cinnamic acid were analysed after extraction with alcohol from the dry plant material. Identification was based on retention times and UV spectra by comparison with commercial standards. Quercetin, kaempferol and (E)-cinnamic acid were separated within 12 min using acetonitrile–aqueous 0.05% ortho-phosphoric acid (40:60 v/v) mobile phase. The method has been successfully applied for the quantitative analysis of all three major components in several samples from different harvests using propylparaben as the internal standard.     

Dimethyl sulfoxide, but not acidosis-induced metallothionein mRNA expression in neonatal rat primary astrocyte cultures is inhibited by the bioflavonoid, quercetin

Metallothionein (MT) mRNA levels were analyzed following exposure of neonatal rat primary astrocyte cultures to physiologic pH (7.4), acidosis (pH 6.5 and 6.0), and dimethyl sulfoxide (DMSO). Treatments were carried out both in the presence and absence of the bioflavonoid, quercetin. Total RNA was probed on northern blots with [α³²P]dCTP-labeled synthetic cDNA probes specific for rat MT isoform mRNAs. MT-I and MT-II mRNA levels in astrocytes exposed to pH 6.5 or pH 6.0 were increased compared to controls (pH 7.4). Treatment with DMSO in the presence and absence of acidosis, also increased MT-I and MT-II mRNA levels compared to controls (pH 7.4). The DMSO-induced increase in MT mRNA expression was reversed by treatment of astrocytes with quercetin, such that MT-I and MT-II mRNA levels in DMSO plus quercetin-treated astrocytes were indistinguishable from mRNA levels in their respective controls at pH 7.4, pH 6.5, and pH 6.0. These findings suggest that both acidosis and DMSO exposure are associated with increased astrocytic MT synthesis at the mRNA level, and that quercetin, effectively blocks MT mRNA induction by DMSO.     

槲皮素对血小板的抑制作用及其机理分析

作者在以往工作的基础上,采用体内外试验观察了槲皮素对血小板的作用。结果发现,槲皮素可显著抑制二磷酸腺苷、胶原、钙离子载体和花生四烯酸诱导的血小板聚集及血小板5—羟色胺的释放反应;槲皮素能减少血小板血栓烷B_2量、升高6—酮—前列腺素F_(1α)量和6—酮—前列腺素F_(1α)/血栓烷B_2的比值。初步探讨了槲皮素的作用机理,认为其主要是通过影响ADP 和TXA_2途径抑制血小板活化。     

槲皮素分子烙印聚合物的单体优化、性能评价及其在薄层色谱分离中的应用

以黄酮类化合物槲皮素为模板,选用甲基丙烯酸(MAA)、丙烯酰胺(AM)、N,N-二乙基胺乙基甲基丙烯酸酯(DEAEM)、2-乙烯吡啶(2-VP)为功能单体,制备对槲皮素具有特定亲和性和选择性的分子烙印聚合物,采用平衡结合实验考察它们对底物的吸附特性,发现以离子作用结合的功能单体2-VP和DEAEM对槲皮素具有较好的烙印效果。研究并将这种烙印聚合物作为薄层色谱的固定相,成功地分离了模板分子及其结构类似物。此外本文还考察了聚合物的粒度和重复使用次数对吸附效果的影响。     

反相高效液相色谱法测定绞股蓝50%总皂苷提取物中芦丁和槲皮素的含量

目的建立绞股蓝50%总皂苷提取物中芦丁与槲皮素的含量测定方法。方法采用高效液相色谱仪,使用TURN-ER KromasilTMC18色谱柱(250 mm×4.6 mm,5μm),流动相为0.4%磷酸水溶液-甲醇-乙腈进行梯度洗脱,流速为0.5 ml.min-1,检测波长为360 nm;柱温为40℃。结果芦丁在0.37~3.70μg范围内有良好的线性关系,r=0.999 9。槲皮素在0.05~0.50μg范围内有良好的线性关系,r=0.999 9;芦丁的平均加样回收率为99.2%,RSD为1.69%;槲皮素的平均加样回收率为99.1%,RSD为2.21%。结论该方法简便快捷,准确度高。     

HPLC法测定黄芪中槲皮素和山奈酚的含量

目的:建立黄芪中槲皮素和山奈酚含量的测定方法。方法:采用反相高效液相色谱法(HPLC)测定不同来源黄芪中槲皮素和山奈酚含量。结果:不同来源样品中2种黄酮苷元的定量分析结果分别为槲皮素平均回收率97.88%,RSD=1.07%;山奈酚平均回收率为99.83%,RSD=1.10%。结论:黄芪中含有槲皮素和山奈酚,其含量随产地而变化。     

芦丁与槲皮素对成骨细胞代谢影响的比较研究

目的:对比研究芦丁(Rutin)与其苷元槲皮素(Quercetin)对成骨细胞形成的影响,以探讨二者防治骨质疏松的作用机理。方法:新生大鼠颅骨分离培养成骨(ROB)细胞,MTT法测定细胞增殖,比色法测定碱性磷酸酶(ALP)活性,茜素红(AR-S)染色法测定矿化结节数,以观察Rutin与Quercetin对ROB细胞骨形成过程中增殖、分化和矿化作用的影响。结果:Quercetin可明显促进ROB细胞的增殖与矿化,故能增强ROB细胞形成活性;Rutin仅能促进ROB细胞增殖,而对矿化作用无影响,却能抑制ROB细胞分化,因而无明显促进骨形成活性。结论:Querce- tin中3-OH形成糖苷(Rutin)后可引起体外培养的成骨细胞活性降低,故含有Rutin的食物或中药防治骨质疏症的机理可能是通过其体内代谢物Quercetin刺激成骨细胞形成而发挥作用的。     

HPLC法测定柴胡属植物地上部分黄酮类含量

目的:建立柴胡属植物地上部分中槲皮素、异鼠李素、山奈素HPLC的含量测定方法。方法:伊利特-C18柱(250 mm×4．6 mm,5μm),以甲醇-水(60:40),磷酸调节pH至3．0为流动相,流速:1．0 ml·min-1,检测波长:360 nm。结果:槲皮素在0．70-5．57μg(r槲=0．999 7),异鼠李素在0．16～1．30μg(r异=0．999 2),山奈素在0．09-0．71μg(r山=0．999 4)范围内呈良好的线性关系。平均回收率分别为97．0％,96．8％,97．4％,RSD分别为2．2％,2．2％,1．1％。结论:本法专属性强,灵敏度高,重现性好,适于黄酮类成分的分离与测定。