Phenolic Compounds of Plants of the Scutellaria L. Genus. Distribution, Structure, and Properties

Information on flavones, flavanones, flavanonols, flavonols, chalcones, isoflavones, biflavonoids, lignoflavonoids, and lignane glycosides and stilbenes isolated from plants of the Scutellaria L. genus was systematized and reviewed. A list of 208 phenolic compounds was given according to flavonoid type with an indication of the plant sources, structures, and physicochemical properties and citations of the original articles.     

RP-HPLC法测定艾纳香中艾纳香素和二氢黄酮醇含量

采用反相高效液相色谱法测定艾纳香中的艾纳香素和二氢黄酮醇含量。确定色谱条件为:色谱柱ZORBAXXDB-C18(4.6mm×150mm,5μm),流动相为V(甲醇)¨V(水)=60¨40,流速0.8ml/min,检测波长290nm,柱温为30℃。在此条件下,艾纳香素和二氢黄酮醇与其它组分得到良好的分离,艾纳香素的线性范围为0.0032～0.048μg/μl(r=0.9999),二氢黄酮醇的线性范围为0.0032～0.048μg/μl(r=0.9993);艾纳香素和二氢黄酮醇的精密度RSD(n=5)分别为1.08%和1.26%,平均回收率(n=5)达98.36%和97.86%。     

MALDI‐MS of flavonoids: a systematic investigation of ionization and in‐source dissociation mechanisms

Matrix assisted laser desorption ionization (MALDI) is a technique widely employed in the analysis of proteins and peptides, and nowadays it has also been applied to small molecules. There is little significant information regarding the in‐source dissociation processes on MALDI for natural products. Twenty‐six flavonoids (flavanones, flavones and flavonols) were analyzed by MALDI using different methods (with different matrices) and without matrix to comprehend the in‐source reactions and establish good analysis methods for these compounds. Depending on the class, structure and the laser intensity applied, methoxylated flavonoid aglycones can eliminate methyl radicals (˙CH₃) in the source, such as flavonols, but lithium 2,4‐dihydroxybenzoate matrix suppresses the ˙CH₃ eliminations and retro‐Diels–Alder cleavages in the source. All of the flavonoid O‐glycosides evaluated herein eliminated the sugar in source, even in the presence of the matrix, and its product radical ions ([M‐H‐sugar]^?˙) were observed in the negative mode. The flavone C‐glycosides suffered intense dissociation, which was reduced by the addition of a matrix and the application of low laser intensity, mainly in the negative mode. Depending on the hydroxyl substituents, the [M‐H‐H]^?˙ ion was observed with variable relative intensity in the spectra. Copyright © 2015 John Wiley & Sons, Ltd.     

3种香叶基取代黄烷酮的合成及抗肿瘤活性

3种香叶基黄烷酮是从毛泡桐(Paulownia tomentosa)水果中分离出的3种具有相似结构的黄酮类化合物。我们以廉价的2,4,6-三羟基苯乙酮,羟基苯甲醛为原料经过取代、氯甲基甲基醚保护、羟醛缩合、分子内的麦克加成反应以及脱甲基甲基醚合成了3个香叶基取代黄烷酮。其结构经过核磁共振氢谱及碳谱(1H NMR,13C NMR)和高分辨质谱(HRMS)等技术手段进行了表征,并采用四氮唑蓝(MTT)法测试了合成化合物对肺癌细胞A459的体外抗肿瘤活性。结果表明,所合成的化合物均具有一定的抗肺癌细胞活性,其中化合物2抗肺癌活性明显优于化合物1和3,其半数抑制浓度为25.6μmol/L,为临床疾病的治疗和药物的研发提供了参考。     

Minor polyphenols from <Emphasis Type="Italic">Maackia amurensis</Emphasis> wood

The rare α,4,2′,4′-tetrahydroxydihydrochalcone, flavanones liquiritigenin and naringenin, isoflavones calycosin and 5-methoxydaidzein, and reduced stilbene dihydroresveratrol were isolated for the first time from Maackia amurensis wood. The structures of the pure compounds were established using 2D NMR COSY, NOE, HMBC, and HSQC experiments. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 575–577, November–December, 2008.     

A review on biological sources,chemistry and pharmacological activities of pinostrobin

Pinostrobin, a dietary bioflavonoid discovered more than 6 decades ago in the heart-wood of pine (Pinus strobus), has depicted many pharmacological activities including anti-viral, anti-oxidant, anti-leukaemic, anti-inflammatory and anti-aromatase activities. It is an inhibitor of sodium channel and Ca²⁺ signalling pathways and also inhibits intestinal smooth muscle contractions. In spite of the fact that pinostrobin has an application as functional foods, till-to-date no comprehensive review on pinostrobin has been carried out. Hence, the present review deals with the biological sources, chemistry and pharmacological activities of pinostrobin.     

Polyphenols from Citrus Tacle® Extract Endowed with HMGCR Inhibitory Activity: An Antihypercholesterolemia Natural Remedy

Tacle^® is a citrus fruit obtained from the crossbreeding of Clementine and Tarocco cultivars. This fruit retains a promising nutraceutical potential most likely due to a high content in polyphenols, among which the main constituents are the two glycosides naringin and hesperidin. Herein, we evaluated, through an in vitro assay, the capability of Tacle extracts to inhibit the hydroxymethylglutaryl-CoA reductase enzyme, which plays a key role in cholesterol biosynthesis. The results obtained spurred us to investigate whether the anti-enzymatic activity observed may be due to a direct interaction of aglycones naringenin and hesperetin with the enzyme catalytic site. Molecular docking simulations indicated that these two compounds are able to anchor to the protein with binding modes and affinities similar to those found for statins, which represent mainstream medications against hypercholesterolemia. The overall results showed an interesting nutraceutical potential of Tacle, suggesting that its extract could be used for dietary supplementation in the treatment of moderate hypercholesterolemia.     

Synthesis and structure elucidation of a series of pyranochromene chalcones and flavanones using 1D and 2D NMR spectroscopy and X‐ray crystallography

A series of novel pyranochromene chalcones and corresponding flavanones were synthesized. This is the first report on the confirmation of the absolute configuration of chromene‐based flavanones using X‐ray crystallography. These compounds were characterized by 2D NMR spectroscopy, and their assignments are reported herein. The 3D structure of the chalcone 3b and flavanone 4g was determined by X‐ray crystallography, and the structure of the flavanone was confirmed to be in the S configuration at C‐2. Copyright © 2014 John Wiley & Sons, Ltd.     

Obtaining new flavanones exhibiting antifungal activities by methyltrioxorhenium-catalyzed epoxidation-methanolysis of flavones

New 3-hydroxy-2-methoxyflavanones have been obtained through epoxidation-methanolysis of the corresponding flavone with urea-hydrogen peroxide (UHP)/methyltrioxorhenium (CH₃ReO₃, MTO) catalytic system in methanol as nucleophilic solvent. After acetylation of the reaction mixtures, the corresponding cis- and trans-3-acetoxy-2-methoxyflavanones have been isolated and characterized by spectroscopic analyses. Their antifungal activity has been tested in vitro against three fungal strains of common saprotrophic soil and seed fungi, such as Trichoderma koningii, Fusarium solani and Cladosporium herbarum, potentially pathogenic for humans. Some aspects of the structure-activity relationship of the most active compounds have been evaluated. The mycelial growth of T. koningii and C. herbarum has been totally inhibited from cis-3-acetoxy-2,6-dimethoxyflavanone 7c and cis-3-acetoxy-2,7-dimethoxyflavanone 13c at the lowest concentration (0.5×10⁻⁴ M).