Antibacterial triterpenoids from the leaves of Ilex hainanensis Merr.

One new triterpenoid (1) and seven known analogues (2–8) were isolated from the leaves of Ilex hainanensis Merr.. Their structures were established by analysis of their MS, 1D and 2D NMR spectroscopic data and comparison with those in the literature. The antibacterial activity of compounds 1–8 were evaluated by determination of minimum inhibitory concentration using twofold microdilution broth method against Streptococcus mutans ATCC 25175 (Gram-positive) and Fusobacterium nucleatum ATCC 10953 (Gram-negative). Compounds 3 and 5 showed significant antibacterial activity against S. mutans in concentration of 9.7 μg/mL, while showed little antibacterial activity against F. nucleatum. On the contrary, the inhibitory activity of compounds 1, 2 and 6 against F. nucleatum were higher than them against S. mutans.     

An HPLC method for simultaneous quantitative determination of seven secoiridoid glucosides separated from the roots of Ilex pubescens

A simple and specific high‐performance liquid chromatographic method has been developed and validated to simultaneously determine seven secoiridoid glucosides for the first time. Three of them were separated from the ethanolic extract of the roots of Ilex pubescens for the first time, namely nuezhenide A, ligusides B and oleonuezhenide. In quantitative analysis, all of the calibration curves showed good linear regression (r > 0.999) within the tested ranges, and the mean recoveries of three different concentrations ranged from 97.6 to 101.2%. The limit of detection and limit of quantification were <4.18 and 11.63 ng mL⁻¹, respectively. The relative standard deviation for repeatability and the precision of seven analytes were <3.4 and 1.9%, respectively. The established method was successfully applied to simultaneous determination of seven secoiridoid glucosides in 11 batches of samples collected from different habitats in China.     

正交试验法优选山绿茶中乌苏酸提取工艺

筛选山绿茶中乌苏酸的最佳提取工艺。采用正交设计L9(34)考察液固比、提取时间、乙醇浓度和提取次数4个因素,用高效液相色谱法测定山绿茶中乌苏酸的含量。山绿茶中乌苏酸的最佳提取工艺为A2B3C3D1,即选择液固比(mL/g)10∶1、提取时间4h、乙醇浓度90%、提取次数1次。本法工艺合理,质量稳定,适宜于工业化生产。     

红外光谱法直接鉴别苦丁茶的研究

本文利用傅立叶变换红外光谱(FTIR)法快速、直接地测定了11种苦丁茶,并对所获得的指纹图谱进行特征峰指认和对比分析。结果表明:各种苦丁茶化学成分相同,而由于各成分间的相对含量的不同,使每种样品都有自己独特的红外谱图,不同产地、不同级别苦丁茶的红外吸收频率、吸收峰的相对强度都存在比较大的差异。同时还运用傅立叶变换红外光谱技术对不同产地、不同级别苦丁茶的混合化学体系进行了全组分快速分析,为苦丁茶的鉴别及质量控制提供了可靠的依据。     

Triterpene saponins with XOD inhibitory activity from the roots of Ilex pubescens

A new triterpene saponin with 28-nor-urs-12(13),18(17)-dien-3β-ol as aglycone,named ilexsaponin C(1) was isolated from the roots of Ilex pubescens,together with three known saponins 2,3 and 4.The structure of 1 was elucidated on the basis of spectral analysis including 1D and 2D NMR and HR-ESI-MS.Saponins 1 and 4 exhibited significant XOD inhibitory activity in the test.     

A pair of new diastereoisomeric phenylpropanoid-substituted flavan from the leaves of Ilex centrochinensis

Abstract

A pair of new diastereoisomeric flavan, containing an additional phenylpropanoid (C₆–C₃) unit in the molecule, has been isolated from the leaves of Ilex centrochinensis. Their structures were identified by extensive spectral analysis and comparison with the data of known analogues.     

MALDI‐ and LDI‐MS saponin fingerprint of leaves and stick components of commercial yerba mate (Ilex paraguariensis)

Yerba mate (YM) is massively produced and consumed as an infusion in South America and spreading all over the world. This product is obtained from dried leaves of Ilex paraguariensis Saint Hilaire, mixed with fragments of dried branches (sticks). For its commercialization, YM must have a minimum percentage of leaves because its presence determines YM quality and price. Till today, a mechanical methodology to determine the relative amount of components (sticks, leaves, and powder) is used. There is not any modern analytical method that provides information for quick characterization of the YM components. Typical saponin fingerprints for leaves and sticks were found by using ultraviolet matrix‐assisted laser desorption ionization and ultraviolet laser desorption ionization mass spectrometry. Then, their possible application as useful tools for quick characterization of components of commercial YM (leaves and sticks) is presented. Furthermore, fingerprints obtained from authentic samples of Ilex paraguariensis and Ilex dumosa are also included and discussed. Each Ilex show typical saponin fingerprints for leaves and sticks.     

Extraction and Crystal Structure of Pedunculoside

The title compound of pedunculoside (C36H58O10), a main active triterpenoid saponin of Ilicis Rotundae Cortex, was isolated from the dried bark of Ilex rotunda Thunb., and characterized by X-ray diffraction analysis. It crystallizes in the orthorhombic system, space group P212121 with C36H58O10, a=13.046(3), b=21.038(4), c=28.413(6) , V=7798.28(3) ·3, Z=8, Dc=1.109 g/cm3, Mr=650.82, F(000)=2832, and μ=0.080 mm-1. The final R=0.0765 and wR=0.1736 for 15117 observed reflections (I > 2σ(I)). The molecular crystal structure of pedunculoside shows relative stereochemistry of 3β,19α,23-trihydroxy-urs-12-en-28-oic acid-28-O-β-D-glucopy- ranosyl ester. The molecule is composed of one glucopyranosyl ring and five six-membered rings with ring junctures of A/B trans, B/C trans, and D/E cis. There are two C36H58O10 molecules in an asymmetric unit, and the title compound is stacked into a 2D layer structure through hydrogen bonds.     

Three New E‐Secoursane Triterpenoid Saponins from the Leaves of Ilex dunniana

Three new triterpenoid saponins with an 18,19‐secours‐13(18)‐ene skeleton, dunnianaolactones A–C ( 1 – 3 , resp.), together with nine known compounds i.e., the ursane‐type triterpene saponin 4 , the two benzofuran lignans 5 and 6 , five flavonoid glycosides, and 4‐hydroxybenzoic acid, were isolated from the leaves of Ilex dunniana Levl . (Aquifoliaceae). Their structures were elucidated by means of spectroscopic and chemical methods. The configuration of dunnianaolactone A ( 1 ) was further confirmed by X‐ray crystal‐structure analysis.