Lipid constituents of Trifolium resupinatum var. microcephalum

The two new compounds (3-methyl-1-nonene-3-ol and 2',3'-dihydroxy propyl pentadecanoate) and four known compounds were isolated from Trifolium resupinatum L. var. microcephalum Zoh. (Leguminosae). All the compounds were reported for the first time from this plant. The stuructures of the isolates were determined by 1D, 2D NMR techniques and MS spectroscopy.     

Two new pyrrolizidine alkaloids from Senecio nemorensis

Two new compounds, including petasinoside A and chloridate-[N-chloromethyl-hectorine], were isolated from Senecio nemorensis. The structures of these compounds were elucidated by spectroscopic methods including 1D and 2D NMR experiments.     

利用选择性激发核磁共振对混合物中的两种化合物进行结构解析

利用现代NMR的1D、2D技术对一个混合物进行了分析。结果表明：混合物由两种化合物组成。为了同时准确确定两种化合物的结构，本工作应用了1D-TOCSY技术，利用该技术选择性强的特点来补充常规的1D、2DHMR实验所提供的分子结构的信息。在没有进行预分离的条件下，顺利地完成了样品中两种化合物的核磁信号归属，并最终确定了它们的结构。     

A New Coumarin and Carbazole Alkaloid from Clausena vestita D. D. Tao

Phytochemical investigation of the EtOH extract of Clausena vestita D. D. Tao led to the isolation of one new coumarin, clauslactone U ( 1 ), and one new carbazole alkaloid, clauszoline N ( 2 ), together with 28 known compounds. The structures of these compounds were established by using MS and 1D‐ and 2D‐NMR techniques, and by comparison with known analogues.     

1H and 13C NMR spectral assignments of four dammarane triterpenoids from carnauba wax

The phytochemical investigation of carnauba wax led to the isolation of three new dammarane triterpenoids 1, 2 and 4, together with the known triterpene 3. The structures of the new compounds were determined by 1D and 2D NMR spectroscopy and by comparison with published data for closely related compounds.     

Isostreptazolin and sannaphenol, two new metabolites from Streptomyces sannanensis

Two new compounds, isostreptazolin (1) and sannaphenol (2), were isolated from the culture broth of Streptomyces sannanensis and their structures elucidated on the basis of 1D and 2D NMR as well as MS, IR and UV spectroscopic data analysis. The cytotoxic activity of 1 and 2 were evaluated. Both compounds were inactive against H460 and HeLa cell lines at 100 mM.     

The isolation and antimicrobial activities of three monocylic sesquiterpenes from Syringa pinnatifolia

We report the isolation of a new sesquiterpene, named as syripinol (1), and two known compounds from the volatile oil of the stems of Syringa pinnatifolia, for the first time. The structures of the isolated compounds were elucidated on the basis of spectroscopic methods including UV, IR, ESI-MS, 1D and 2D NMR techniques. The antibacterial activities of the compounds were also evaluated against various bacteria which showed good results.     

Complete 1H and 13C data assignments of two new guaianolides isolated from Ainsliaea fragrans

Two new guaianolides, 8alpha-hydroxy-11alpha,13-dihydroglucozaluzanin C and 11alpha,13-dihydroglucozaluzanin C, were isolated from Ainsliaea fragrans, along with two known guaianolides, 8alpha-hydroxy-11alpha,13-dihydrozaluzanin C and glucozaluzanin C. The structures of the new compounds were unambiguously established by HR-ESI-MS, one-dimensional (1D) (DEPT), two-dimensional (2D) ((1)H-(1)H COSY, HSQC, HMBC, ROESY) NMR experiments and by comparison with structurally related compounds. The known compounds were identified by comparison of spectral data with published references. Some NMR data of the known compounds were reported for the first time.     

Spicachlorantins G-J, new lindenane sesquiterpenoid dimers from the roots of Chloranthus spicatus

Four new lindenane sesquiterpenoid dimers, spicachlorantins G-J (1-4), were isolated from the roots of Chloranthus spicatus together with seven known compounds, including chloramultilide A, shizukaol B, shizukaol D, shizukaol F, shizukaol P, chlorahololide D, and cycloshizukaol A. The planar structures of the new compounds were established by 1D-, 2D-NMR, and MS analyses. The absolute configurations of these compounds were determined by analyzing rotating Overhauser enhancement and exchange spectroscopy (ROESY) and circular dichroism (CD) spectra.     

Negombins A-I, new chlorinated polyfunctional diterpenoids from the marine sponge Negombata species

Nine novel compounds designated negombins A-I (1-9) were isolated, together with latrunculin, from the Tanzanian sponge Negombata sp. The nine are sacculatane type diterpenes, previously only known from liverworts. The structures of the compounds were elucidated by interpretation of MS and 1D and 2D NMR spectra. A possible biogenesis initiated by the naturally rare chloronium ion is suggested, possibly hinting to a guest microorganism as the source of the compounds. Compound 4 is toxic to brine shrimp larvae.     

毛细管区带电泳测定D1蛋白酶的活性及其抑制剂先导化合物的筛选

建立了毛细管区带电泳技术快速测定D1蛋白酶活性及其抑制剂先导化合物的筛选方法。实验选用未涂层熔融石英毛细管(43 cm 5mm)和磷酸盐缓冲溶液(50 mmol/L, pH 3.0)作为分离介质,运行电压18 kV,测定了D1蛋白酶的活性并对部分抑制剂先导化合物进行了筛选。结果表明, ITP26和ITP21两种异噁唑噻唑哌啶类先导化合物对蛋白酶活性具有抑制作用,抑制率分别为26%和13%。     

Selectable one-dimensional or two-dimensional gas chromatography-olfactometry/mass spectrometry with preparative fraction collection for analysis of ultra-trace amounts of odor compounds

A novel selectable one-dimensional ((1)D) or two-dimensional ((2)D) gas chromatography-olfactometry/mass spectrometry with preparative fraction collection (selectable (1)D/(2)D GC-O/MS with PFC) system was developed. The main advantages of this system are the simple and fast selection of (1)D GC-O/MS or (2)D GC-O/MS or (1)D GC-PFC or (2)D GC-PFC operation with a mouse click (without any instrumental set-up change), and total transfer of enriched compounds with thermal desorption (TD) on the same system for identification with (2)D GC-O/MS analysis. Recovery of PFC enrichment with 20 injection cycles of 15 model compounds at 500pg each (e.g. alcohol, aldehyde, ester, lactone, and phenol) was very good with recoveries in the range of 98-116%. The feasibility and benefit of the proposed system was demonstrated with an identification of off-flavor compounds (e.g. 2,4,6-trichloroanisole (TCA), 2-isobutyl-3-methoxypyrazine (IBMP), and geosmin) in spiked wine at odor perception threshold level (5-50ngL(-1)). After parallel stir bar sorptive extraction (SBSE) for 20 aliquots of a sample and subsequent PFC enrichment for the odor-active fractions from the 20 stir bars, three off-flavor compounds were clearly resolved and detected with TD-(2)D GC-O/MS in scan mode. The good efficiency of SBSE-PFC enrichment in the range of 71-78% shows that all analytical steps, e.g. SBSE, TD, (1)D/(2)D GC-O/MS, and PFC, are quantitative and identification of off-flavor compounds at ngL(-1) level in wine is possible.     

Three New Phenol Compounds from Iris dichotoma Pall.

Three new phenolic compounds, irisdichototins D, E, and F ( 1 – 3 , resp.) were isolated from the stems of Iris dichotoma. The structures of the new compounds were elucidated by spectroscopic analyses, including 2D‐NMR techniques.     

Two compounds from the endophytic Colletotrichum sp. of Ginkgo biloba

Two compounds, apigenin-8-C-beta-D-glucopyranoside and 2-(hydroxymethylthio)ethanol, were extracted from the fermentation products of a strain of endophytic fungus, Colletotrichum sp. NTB-2, isolated from the leafstalk of Ginkgo biloba. The structures of the two compounds were determined on the basis of extensive spectroscopic analysis, including 1D and 2D NMR spectral data. The compounds wereobtained from microorganisms for the first time.     

Employing ultra high pressure liquid chromatography as the second dimension in a comprehensive two-dimensional system for analysis of Stevia rebaudiana extracts

Stevia rebaudiana extracts and plant materials are increasingly used as natural sweeteners. Polyphenolic and stevioside compounds contained in S. rebaudiana extracts were separated by comprehensive LC. A polyamine column operated in normal phase mode was used for the first dimension separation (D1), and a UHPLC C18 column operated in reversed phase mode was used for the second dimension separation (D2). The sub-2 μm column (2.1 mm × 30 mm, maintained at 70°C) and the UHPLC pump employed for D2 elution allowed a separation/cycle time of 20 s, with a backpressure oscillating between 805 and 922 bar at 3.4 mL/min. The reduced D2 cycle time allowed 3-12 D2 samplings for each peak eluted by D1. Polyphenolic and stevioside compounds were identified by combining the information coming from the position of the compounds in the 2D plot and UV spectra with that of reference materials.     

锦灯笼果实的化学成分研究

从锦灯笼中分离得到5个甾体类化合物,分别鉴定为酸浆素A(1,alkekengilin A)、酸浆素B(2,alkekengilin B)、酸浆苦素D(3,physalin D)、酸浆苦素P(4,physalin P)、4,7-二去氢新酸浆苦素B(5,4,7-didehydro-neophysalin B).其中酸浆素A(1,alkekengilin A)和酸浆素B(2,alkekengilin B)为新的天然产物.运用现代波谱技术对上述化合物的结构进行了确证.     

Sesquiterpene compounds from Inula viscosa

Two new compounds, 2,5-dihydroxyisocostic acid and 2,3-dihydroxycostic acid together with three known sesquiterpene compounds, Isocostic acid, Carabrone and Tomentosin, have been isolated from the acetone extract of Inula viscosa (L.) Aiton. The structures of all new compounds were determined by spectroscopic methods, in particular 1D and 2D (1)H- and (13)C-NMR. The (13)C-NMR spectra of Isocostic acid and of Tomentosin are reported here for the first time.     

Long-chain alkanoic acid esters of lupeol from Dorstenia harmsiana Engl. (Moraceae)

In addition to lupeol (1a), three long-chain alkanoic acid esters of lupeol, in which two were new, were isolated from the hexane and ethyl acetate twigs extract of Dorstenia harmsiana Engl. (Moraceae). The structures of the new compounds were elucidated on the basis of 1D and 2D NMR experiments. Some isolated compounds were evaluated for their antimicrobial activities. The lupeol and its three long-chain alkanoic acid esters showed antifungal and antibacterial activities.     

Auroglaucin-related neuroprotective compounds from Vietnamese marine sediment-derived fungus Aspergillus niveoglaucus

Abstract

Two new auroglaucin-derived compounds, niveoglaucins A (1) and B (2), together with four known related compounds were isolated from extract of the marine sediment-derived strain of Aspergillus niveoglaucus. The structures of these compounds were determined by 1D and 2D NMR spectroscopy and high resolution MS. The plausible biosynthetic pathway was proposed for new compounds 1 and 2. The neuroprotective activity in 6-OHDA-induced Parkinson’s disease cell model was shown for niveoglaucin A (1).     

二腈基衍生物的合成及其光限幅性质

设计并合成了一系列含不同末端给电子基团及共轭链长度的1,1-二腈基-2,2-二苯基乙烯类化合物(D1-D7),用核磁共振氢谱(1H NMR)、核磁共振碳谱(13C NMR)和高分辨质谱(HRMS)对分子结构进行了表征.选用N,N-二甲基甲酰胺(DMF)为溶剂,测定了它们的线性光物理性质,用光漂白法研究了它们的光稳定性,用热失重法测试了它们的热稳定性.研究了这7个化合物针对800 nm脉冲激光(掺钛蓝宝石激光器,脉冲宽度~130 fs,重复频率1000 Hz)的光限幅性质.结果表明:以二烷基氨基为给电子基团的4个化合物(D4-D7)对800 nm的飞秒脉冲激光均具有显著的光限幅性能,限幅机制为双光子吸收(2PA),而端基给电子能力较弱、共轭链长较短的D1-D3光限幅效果并不明显.此外,D4-D7都具有较好的热稳定性和光稳定性.而且,该系列化合物的双光子吸收截面、光稳定性和热稳定性都具有随分子结构中给电子基团增强或共轭链增长而增大或提高的趋势.D7具有最好的综合性能,是一个有应用潜力的光限幅材料.