Flavonoids from the leaves ofRhododendron brachycarpum

The flavonoids isolated from the leaves ofRhododendron brachycarpum, were identified as quercetin, avicularin, quercitrin and hyperin.     

维吾尔药孜尔克中总黄酮、微量元素及脂肪含量的测定

目的:对维吾尔医药孜尔克中总黄酮、微量元素及脂肪含量进行测定。方法:采用分光光度法,测定孜尔克的根和果实中总黄酮的含量。采用索氏抽提法提取并测定孜尔克的根和果实的脂肪含量。用原子吸收分光光度法测定孜尔克中根和果实中钙、铁、钠、钾、铜、锌、锰7种微量元素。结果:总黄酮在0.006~0.06mg.ml-1之间与吸光度有良好的线性关系。回归方程:C=0.0732A-0.002267(mg.ml-1)。相关系数R2=0.9916。元素测定中钙、铁含量较高。结论:本法操作简便,快速,为进一步研究和综合开发利用这一民族药材提供了依据。     

GC-MS analysis,determination of total phenolics,flavonoid content and free radical scavenging activities of various crude extracts of Moringa peregrina (Forssk.) Fiori leaves

ObjectiveTo perform phytochemical screening, estimate total phenolics, flavonoids and to evaluate antioxidant potential of Moringa peregrina (M. peregrina) leaves.MethodsThe dried powdered leaves of M. peregrina (150 g) were extracted exhaustively by Soxhlet with ethanol and then fractionated into hexane, chloroform, ethy alacetate and methanol. All the prepared extracts were also analyzed by gas chromatography-mass spectrometry to identify and characterize the chemical compounds present in the crude extracts. Folin- Ciocalteu reagent and aluminium chloride colorimetric methods were used to estimate total phenolic and flavonoid content of extracts. Hydrogen peroxide and 1,1 diphenyl -2-picrylhydrazyl were used to determine in vitro antioxidant activity.ResultsPhytochemical analysis of ethanol extract showed presence of major classes of phytochemicals. Gas chromatography-mass spectrometry results revealed presence of 19 phytoconstituents in hexane extract, 6 in ethyl acetate and 7 compounds in methanolic extract. Methanol extract was found to contain the highest phenolic content and flavonoids. In vitro antioxidant activities of all crude extracts were significant and comparable with the standard ascorbic acid.ConclusionsResults of this study show that the leaves of M. peregrina are the rich source of phenolic compounds that can play an important role in preventing the progression of many diseases.     

The flavonoid rutin and its aglycone quercetin modulate the microglia inflammatory profile improving antiglioma activity

Microglia cells are the immune effector in the Central Nervous System (CNS). However, studies have showed that they contribute more to glioma progression than to its elimination. Rutin and its aglycone quercetin are flavonoids present in many fruits as well as plants and have been demonstrated to bear anti-inflammatory, antioxidant and antitumor properties also to human glioblastoma cell lines. Previous studies also demonstrated that rutin, isolated from the Brazilian plant Dimorphandra mollis Bent., presents immunomodulatory effect on astrocytes and microglia. In this study, we investigate the antitumor and immunomodulatory properties of rutin and its aglycone quercetin on the viability of glioma cells alone and under direct and indirect interaction with microglia. Flavonoid treatment of rat C6 glioma cells induced inhibition of proliferation and migration, and also induced microglia chemotaxis that was associated to the up regulation of tumor necrosis factor (TNF) and the down regulation of Interleukin 10 (IL-10) at protein and mRNA expression levels, regulation of mRNA expression for chemokines CCL2, CCL5 and CX3CL1, and Heparin Binding Growth Factor (HDGF), Insulin-like growth factor (IGF) and Glial cell-derived neurotrophic factor (GDNF) growth factors. Treatment of human U251 and TG1 glioblastoma cells with both flavonoids also modulated negatively the expression of mRNA for IL-6 and IL-10 and positively the expression of mRNA for TNF characterizing changes to the immune regulatory profile. Treatment of microglia and C6 cells either in co-cultures or during indirect interaction, via conditioned media from glioma cells treated with flavonoids or via conditioned media from microglia treated with flavonoids reduced proliferation and migration of glioma cells. It also directed microglia towards an inflammatory profile with increased expression of mRNA for IL-1β, IL-6, IL-18 and decreased expression of mRNA for nitric oxide synthase 2 (NOS2) and prostaglandin-endoperoxide synthase 2 (PTGS2), arginase and transforming growth factor beta (TGF-β), as well as Insulin-like growth factor (IGF). Treatment of U251 cells with flavonoids also reduced tumorigenesis when the cells were xenotransplanted in rat brains, and directed microglia and also astrocytes in the microenvironment of tumor cell implantation as well as in the brain parenchyma to a not favorable molecular inflammatory profile to the glioma growth, as observed in cultures. Together these results demonstrate that the flavonoid rutin and its aglycone quercetin present antiglioma effects related to the property of modulating the microglial inflammatory profile and may be considered for molecular and preclinical studies as adjuvant molecules for treatment of gliomas.     

Suppressive Effects of the Flavonoids Quercetin and Luteolin on the Accumulation of Lipid Rafts after Signal Transduction via Receptors

Quercetin (QUER) and luteolin (LUTE) are dietary flavonoids capable of regulating the production of cytokines, such as tumor necrosis factor-α (TNF-α), and interleukin-6 (IL-6). However, their mechanisms of action are not fully understood. In lipopolysaccharide-triggered (LPS)-triggered signaling via Toll-like receptor 4 (TLR4), QUER and LUTE suppresses not only the degradation of the inhibitor of κB (IκB), with resultant activation of nuclear factor-κB (NF-κB), but also the phosphorylation of p38 and Akt in bone marrow-derived macrophages that have been stimulated with LPS. We report here that, in TNF-α-induced signaling, QUER and LUTE significantly suppressed the production of IL-6 and activation of NF-κB. Accumulation of lipid rafts, the initial step in the signaling pathway, was significantly inhibited when macrophages were treated with QUER or with LUTE prior to exposure to LPS. Similarly, the accumulation of lipid rafts was inhibited by the flavonoids when B cells were activated via the membrane IgM and when T cells were activated via CD3. In contrast, QUER and LUTE did not inhibit the activation of phorbol myristate acetate-induced NF-κB in macrophages. Our observations suggest that QUER and LUTE interact with receptors on the cell surface and suppress the accumulation of lipid rafts that occurs downstream of the activation of the receptors.     

Antiviral Activity of Chrysin Derivatives against Coxsackievirus B3 in vitro and in vivo

Chrysin is a 5,7-dihydroxyflavone and was recently shown to potently inhibit enterovirus 71 (EV71) by suppressing viral 3C protease (3C^pro) activity. In the current study, we investigated whether chrysin also shows antiviral activity against coxsackievirus B3 (CVB3), which belongs to the same genus (Enterovirus) as EV71, and assessed its ability to prevent the resulting acute pancreatitis and myocarditis. We found that chrysin showed antiviral activity against CVB3 at 10 μM, but exhibited mild cellular cytotoxicity at 50 μM, prompting us to synthesize derivatives of chrysin to increase the antiviral activity and reduce its cytotoxicity. Among four 4-substituted benzyl derivatives derived from C(5) benzyl-protected derivatives 7, 9–11 had significant antiviral activity and showed the most potent activity against CVB3 with low cytotoxicity in Vero cells. Intraperitoneal injection of CVB3 in BALB/c mice with 1×10⁶ TCID₅₀ (50% tissue culture infective dose) of CVB3 induced acute pancreatitis with ablation of acinar cells and increased serum CXCL1 levels, whereas the daily administration of 9 for 5 days significantly alleviated the pancreatic inflammation and reduced the elevation in serum CXCL1 levels. Collectively, we assessed the anti-CVB3 activities of chrysin and its derivatives, and found that among 4-substituted benzyl derivatives, 9 exhibited the highest activity against CVB3 in vivo, and protected mice from CVB3-induced pancreatic damage, simultaneously lowering serum CXCL1 levels.     

高空环境对鸡冠花黄酮类化合物合成的诱变效应

目的 探讨高空环境对鸡冠花黄酮类化合物合成的影响。方法 利用高空气球搭载了两个品种鸡冠花(Celosia cristata L.)的种子,进行空间诱变处理。飞行高度为40.112km,飞行时间近4h,回收后播种栽培,采收子一代(SP1)花序。将各组样品花序的乙醇提取物与Mg+HCl,Zn+HCl,1%FeCl3-乙醇液,2%AlCl3-乙醇液,1%NaOH进行显色反应,呈现黄酮类化合物性质特征颜色。又以槲皮素、山柰酚、异鼠李素为对照品,采用HPLC法测定分析了各搭载组花序中黄酮醇的含量,并与地面对照组比较。结果 两个品种鸡冠花搭载组花序中黄酮醇总量分别为0.91%、0.424%,比对照组分别提高116.00%、68.25%,异鼠李素含量的增幅最为显著,槲皮素含量的变动则不一致。结论 高空环境诱变处理对鸡冠花花序中黄酮类化合物合成产生了显著效应。     

高效液相色谱法测定复方银杏叶片中银杏总黄酮的含量

目的建立复方银杏叶片中银杏总黄酮含量测定方法。方法采用高效液相色谱法,用Symmetry-C18色谱柱(250mm×4.6 mm,5μm),以甲醇-0.4%磷酸溶液(52∶48)为流动相,流速为1.0 ml.min-1,检测波长360 nm,柱温35℃。结果该法线性关系良好,平均加样回收率为98.35%,RSD为1.17%(n=5)。结论该法操作简便,分离效果好,结果准确,专属性强,可作为复方银杏叶片的质量控制方法。     

Stereospecific high-performance liquid chromatographic validation of homoeriodictyol in serum and Yerba Santa (Eriodictyon glutinosum)

A stereospecific method of analysis of racemic homoeriodictyol (eriodictyol 3′-methyl ether) in biological fluids is necessary to study pharmacokinetics and disposition in fruits and herbs. A simple high-performance liquid chromatographic method was developed for the determination of homoeriodictyol enantiomers. Separation was achieved in a Chiralcel^® OJ-RH column with UV-detection at 288 nm. The standard curves in serum were linear ranging from 0.5 to 100.0 μg/ml for each enantiomer. The mean extraction efficiency was >88.0%. Precision of the assay was <15% (CV), and was within 12% at the limit of quantitation (0.5 μg/ml). Bias of the assay was <15%, and was within 6% at the limit of quantitation. The assay was applied successfully to stereospecific disposition of homoeriodictyol enantiomers in rats and to the quantification of homoeriodictyol enantiomers in Yerba Santa (Eriodictyon glutinosum).     

可见光及紫外光分光光度法测定丁香总黄酮含量的研究

目的研究可见光及紫外分光光度法测定丁香总黄酮含量的方法。方法可见光分光光度法是以芦丁为参照品,硝酸铝作显色剂,在510 nm波长测定总黄酮含量。紫外分光光度法是以芦丁为参照品,在359 nm波长测定总黄酮含量。结果可见光法平均回收率是99.46%,紫外光法是99.13%。RSD分别是1.15%和0.90%。结论紫外分光光度法是一种较理想的测定方法。