Synthesis and studies of antibacterial activity of pongaglabol

Pongaglabol [8-hydroxy-5-phenyl-furo[2,3-h]benzo(b)pyran-7-one] was synthesized and tested for antibacterial effects againstShigella dysenteriae, Salmonella typhi, Streptococcus β-haemolyticus andStaphylococcus aureus. The synthesized compounds were characterized using UV, IR and¹H NMR spectral data     

地锦草总黄酮最佳提取分离工艺的研究

采用四因素三水平的正交实验方法,对地锦草总黄酮的最佳提取工艺进行了探索.采用乙酸乙酯萃取、酸碱沉淀、铅盐沉淀3种方法,对其最佳分离工艺进行了探索.正交实验结果表明:温浸法中四因素对地锦草黄酮的影响顺序为乙醇浓度>样液比>提取温度>提取时间.通过实验得到了地锦草总黄酮的最佳提取工艺:以10倍体积的50%的乙醇水溶液在80℃浸提1 h.地锦草总黄酮的最佳分离方法为酸碱沉淀法.这些数据为中药地锦草的开发和应用提供了科学依据.     

Synthesis of 2,2’-Biflavanones from Flavone via Electroreduction and Photolysis

Biflavonoids, widely distributed in natural plants, had strong biological activities including spasmolysis, peripheral vasodilatation, antibradykinin activity and antispasmogenic action against prostaglandin PGE1, inhibition of cyclic GMP and cyclic AMP phosphodiesterase and inhibition of hepatoma cells. Recently, some biflavonoids were demonstrated to enhance suppersion of lymphocyte proliferation, inhibition of phospholipaseCr1, anti-inflammatory activity, anti-HIV activity, anticompleme…     

A new flavone from Malaysia Borneo Marsdenia tinctoria

Marsdenia tinctoria is an indigo producing plant commonly found in Borneo, Malaysia. In this present study, one new flavone kapitone (1) and three known compounds, that is 3,2’-dihydroxyflavone (2), 1-methylcyclobutene (3) and dimethyl isatoate (4) were isolated from the Malaysia Borneo M. tinctoria R. Br. (Apocynaceae). These compounds were isolated and characterised using extensive chromatographic and spectroscopic methods.     

Penimethavone A,a flavone from a gorgonian-derived fungus Penicillium chrysogenum

A novel flavone, penimethavone A (1), possessing a rare unique methyl group at ring-B, was isolated from the fungus Penicillium chrysogenum cultured from a gorgonian Carijoa sp. collected from the South China Sea. The structure was elucidated by extensive spectroscopic analysis and by comparison with related known compound. Compound 1 showed selective and moderate cytotoxicity against cervical cancer (HeLa) and rhabdomyosarcoma cell lines with IC₅₀ values of 8.41 and 8.18 μM, respectively.     

Flavone-Rich Fractions and Extracts from Oroxylum indicum and Their Antibacterial Activities against Clinically Isolated Zoonotic Bacteria and Free Radical Scavenging Effects

Oroxylum indicum extracts from the seeds collected from Lampang and Pattani provinces in Thailand, and young fruits and flowers exhibited in vitro display antioxidant and antibacterial activities against clinically isolated zoonotic bacteria including Staphylococcus intermedius, Streptococcus suis, Pseudomonas aeruginosa, β-hemolytic Escherichia coli and Staphylococcus aureus. The orange crystals and yellow precipitates were obtained from the preparation processes of the seed extracts. The orange-red crystals from the seeds collected from Lampang province exhibited strong in vitro 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging effects (EC₅₀ value = 25.99 ± 3.30 μg/mL) and antibacterial effects on S. intermedius and β-hemolytic E. coli while the yellow precipitate from the same source exhibited only antioxidant activity. Quantitative analysis of phytochemicals in O. indicum samples by spectrophotometric and HPLC techniques showed that they contained different amounts of total phenolic, total flavonoid and three major flavones; baicalin, baicalein and chrysin contents. Young fruit extract, which contained low amounts of flavone contents, still promoted antibacterial effects against the tested bacteria with IC₅₀ values lower than 1 mg/mL and MIC values between 4 to 10 mg/mL in S. intermedius, S. aureus and S suis while higher IC₅₀ and MIC values against P. aeruginosa and β-hemolytic E. coli were found. From scanning electron microscopy, the extract of the young fruit of O. indicum promoted morphological changes in the bacterial cells by disrupting the bacterial cell walls, inducing leakage of the cellular content, and generating the abnormal accumulation of cells. The mechanism of action of the extract for this antibacterial effect may be the disruption of the cell membrane and abnormal cell aggregations. Regression analysis of the results suggests the correlation between total phenolic and total flavonoid contents and antioxidant and antibacterial effects. Baicalin was found to have a high correlation with an inhibitory effect against β-hemolytic E. coli while three unidentified peaks, which could be flavones, showed high correlations with an inhibitory effect against S. intermedius, S. suis, P. aeruginosa and S. aureus.     

Approach to the study of flavone di‐C‐glycosides by high performance liquid chromatography‐tandem ion trap mass spectrometry and its application to characterization of flavonoid composition in Viola yedoensis

The mass spectrometric (MS) analysis of flavone di‐C‐glycosides has been a difficult task due to pure standards being unavailable commercially and to that the reported relative intensities of some diagnostic ions varied with MS instruments. In this study, five flavone di‐C‐glycoside standards from Viola yedoensis have been systematically studied by high performance liquid chromatography‐electrospray ionization‐tandem ion trap mass spectrometry (HPLC‐ESI‐IT‐MSⁿ) in the negative ion mode to analyze their fragmentation patterns. A new MS² and MS³ hierarchical fragmentation for the identification of the sugar nature (hexoses or pentoses) at C‐6 and C‐8 is presented based on previously established rules of fragmentation. Here, for the first time, we report that the MS² and MS³ structure‐diagnostic fragments about the glycosylation types and positions are highly dependent on the configuration of the sugars at C‐6 and C‐8. The base peak (^0,2X₁^0,2X₂^? ion) in MS³ spectra of di‐C‐glycosides could be used as a diagnostic ion for flavone aglycones. These newly proposed fragmentation behaviors have been successfully applied to the characterization of flavone di‐C‐glycosides found in V. yedoensis. A total of 35 flavonoid glycosides, including 1 flavone mono‐C‐hexoside, 2 flavone 6,8‐di‐C‐hexosides, 11 flavone 6,8‐di‐C‐pentosides, 13 flavone 6,8‐C‐hexosyl‐C‐pentosides, 5 acetylated flavone C‐glycosides and 3 flavonol O‐glycosides, were identified or tentatively identified on the base of their UV profiles, MS and MSⁿ (n = 5) data, or by comparing with reference substances. Among these, the acetylated flavone C‐glycosides were reported from V. yedoensis for the first time. Copyright © 2014 John Wiley & Sons, Ltd.     

茶叶中总黄酮含量测定方法的研究

茶叶中富含羟基苯甲酸类、肉桂酸类及原花色素等多酚类物质,这些物质都具有邻苯二羟基结构,碱性环境下与铝离子形成络合物,影响总黄酮的测定。本实验用亚硝酸钠-硝酸铝法和三氯化铝法测定茶叶总黄酮含量的结果作了比较。实验结果表明,亚硝酸钠-硝酸铝法的测定结果比三氯化铝法约高60mg/g,三氯化铝法在酸性环境下进行,酸度实验显示,适宜酸度为pH≥5.0。鞣酸干扰实验表明,平均误差为0.017mg,随着鞣酸量的增加,测得值无上升趋势。三氯化铝法的线性方程:y=0.000638 0.8623x,相关系数:r=0.9998;样品加标回收率为98.05%。因此,对含酚类较多的植物应采用三氯化铝法测定其总黄酮的含量。     

豆腐果苷-喹啉和黄酮衍生物的合成及镇静活性研究

以L-脯氨酸为有机催化剂一步合成了豆腐果苷-喹啉酮(2),在此基础上合成了一系列豆腐果苷-喹啉衍生物3a～3c,4和5a～5c;以苄溴、豆腐果苷、邻羟基苯乙酮,氨基脲盐酸盐、羟胺盐酸盐、甲氧基胺盐酸盐为原料合成出豆腐果苷-黄酮衍生物8和9a～9c.产物结构经1H NMR,IR和HRMS确认.初步生物活性测试结果表明5b和9b具有较好的镇静催眠活性.     

A new flavone C-glucoside from Glycosmis arborea (Rutaceae)

<正>A new C-glycosyl flavone 7,4'-dihydroxy-5-methoxyflavone-6-C-β-D-glucopyranoside 1 has been isolated and characterized form ethanolic extract of leaves part of Glycosmis arborea.The structure of compound was verified by means of high field 1D and 2D NMR(DEFT,COSY,DQF-HSQC,HMBC) and HRMS spectral analysis,respectively.