一株红树来源真菌Penicillium citrinum HL-5126中两个新异香豆素化合物（英文）

综合运用多种现代色谱学分离方法对红树来源真菌Penicillium citrinum HL-5126中的次级代谢产物进行了研究,从中分离获得2个新的异香豆素类化合物,通过1DNMR,2DNMR和HR-ESI-MS等波谱鉴定技术确定结构分别为penicimarin J (1)和penicimarin K (2).通过测定圆二色谱并与文献数据对照,确定了化合物1和2的绝对构型.化合物1和2对α-Glucosidase显示一定的抑制活性, IC50值分别为18.37和25.86μg/mL.     

两个新的海绵烷型二萜内酯

从海绵SpongiazimoccasubspeciesirregulariaLemdenfeld中分离到2个新的海绵烷型二萜(2),(3),依次命名为zimoclatoneB和zimoclactoeC。应用1D和2DNMR和X射线单晶衍射分析方法测定了这两个新二萜的化学结构及相对构型。     

杂环生物碱类化合物的分离及结构鉴定

首次报道从中国南海西沙群岛海绵spongiaobligue中分离得到3个新的含氮生物碱杂环化合物,通过MS,1DNMR,20NMR等波谱数据及元素分析确定它们的结构。     

柱色谱法分离地榆中的鞣质和皂甙

柱色谱法分离地榆中的鞣质和皂甙王满力，陈桐（贵州工学院化工系贵阳５５０００３）ｌ前言从中草药植物中革取的鞣质和皂甙极不易分离，严重地制约了它们的开发利用￣［１，２］。本文采用色谱半干柱酸度梯度淋洗法￣［２，３］，可将地榆中鞣质和皂甙完全分离，并观察到...     

低交换量大孔弱碱树脂的合成、表征及其对绞股蓝皂甙的吸附性能

为筛选适用于天然皂甙分离纯化的吸附树脂,以高交联聚苯乙烯型大孔树脂S-008(Ⅰ)为原料,经氯甲基化和胺化反应,合成了低交换量弱碱树脂(Ⅱ—Ⅴ)。然后,对其结构进行了表征,测定了它们对绞股蓝皂甙的吸附性能。结果说明,胺化试剂与反应条件影响产物树脂的结构,并进而影响产物树脂对绞股蓝皂甙的吸附性能。     

内生真菌叶下珠生拟茎点霉的次级代谢产物研究（英文）

从广藿香内生真菌叶下珠生拟茎点霉(PhomopsisphyllanthicolaA658)中分离纯化得到6个聚酮类化合物,分别鉴定为dothioreloneO(1),2-[3,5-二羟基-2-(7-羟基辛酰基)苯基]乙酸(2),dothioreloneM(3),dothioreloneK(4),cytosporoneB(5),和cytosporoneC(6).其中化合物1为新化合物,化合物2为新天然产物,新化合物的结构进一步通过HR-ESIMS,1DNMR和2DNMR等光谱技术确定.此外,对分离所得的化合物进行了体外细胞毒测试,结果表明化合物3～5显示出不同程度的细胞毒活性.     

石杉碱O的结构鉴定

蛇足石杉[Huperziaserrata(Thunb.)Trev.]中,R~f与石杉碱甲相近部位分离得到一个新生物碱,经IR,MS,1D和2DNMR确定了其化学结构,为一个有内氢键烯醇型新的lycopodine类生物碱,命名为石杉碱O(HuperzineO)。     

交联聚(乙烯基苯乙酮)树脂的合成、表征及其对绞股蓝皂甙的吸附性能

为筛选适合于天然皂甙分离的吸附树脂,我们通过交联聚装乙烯的FriedelGrafts酰化反应,合成了一系列交联聚(乙烯基苯乙酮)树脂Ⅰ—Ⅸ,用红外光谱/元素分析方法测定了树脂的羰基含量,并对其物理结构进行了表征。树脂对绞股蓝皂甙的静态吸附实验说明,只有具有较高羰基含量和较大比表面的树脂才能对水溶液中的皂甙表现出较大的吸附量。     

高效液相色谱质谱质谱法分析人参皂甙

 以反相高效液相色谱法分离了 9种人参皂甙。操作条件为乙腈 水梯度洗脱 ,二极管阵列检测器检测并在2 0 2nm下提取色谱图。利用三级四极杆质谱研究了 9种人参皂甙的一级质谱 (主要给出相对分子质量信息 )和二级质谱 (提供碎片结构信息 )。通过它们质谱图的差异对其进行了鉴别 ,并将方法用于实际样品中的 9种人参皂甙的定性。     

人参皂甙的反相高效液相色谱多台阶梯度优化方法

建立了一种反相高效液相色谱多台阶梯度分离人参皂甙的方法.该方法以乙腈-水溶液为流动相,通过一系列等度实验,获得了8种人参皂甙Rg1,Re,Rf,Rg2,Rb1,Rc,Rb2和Rd的色谱保留参数,发现两参数保留方程不适合用于人参皂甙这种天然产物的分离条件的优化,而三参数保留方程的高精度才可满足预测的要求.在三参数保留方程的基础上,通过计算确定了8种人参皂甙(包括3台阶梯度)的液相色谱分离条件.通过实验对此优化条件进行了验证,实验结果显示了较好的预测精度和分离度.将本方法用于分离人参皂甙,分析时间短且分离度高,显示了等度台阶梯度优化方法对确定色谱分离条件的优越性.     

Sesquiterpenes from the leaves of Nicotiana tabacum and their anti-tobacco mosaic virus activity

In searching for more bioactive compounds, phytochemical investigations on the acetone extract of the leaves of Nicotiana tabacum resulted in the isolation of two new sesquiterpenes, nicosesquiterpene A and B(1 and 2), along with four known sesquiterpene derivatives(3–6). Structural elucidation of 1 and 2 was performed by spectral methods, such as HRMS, IR, UV, 1D and 2D NMR spectroscopy. Compounds 1 and 2are the first naturally occurring pterosin-type sesquiterpene bearing an isopropyl moiety. Compounds1–6 were also evaluated for their anti-tobacco mosaic virus(anti-TMV) activity. The results showed that compounds 1 and 2 exhibited high anti-TMV activity with inhibition rates of 36.7% and 45.6%,respectively, which is higher than that of positive control. The other compounds also showed potential activity with inhibition rates in the range of 22.7%–29.2%.     

Isolation and structural elucidation of a novel rotenoid from the seeds of Clitoria fairchildiana

The seeds of Clitoria fairchildiana provided a new rotenoid, 6-hydroxy-2,3,9-trimethoxy-[1]benzopyrano[3,4-b][1]benzopyran-12(6H)-one. The structural elucidation was performed using detailed analyses of H- and 13C-NMR spectra including 2DNMR spectroscopic techniques (1H-13CHETCOR) and by comparison with spectrometric data from the literature. The anti-inflammatory activity was investigated using a capillary permeability assay.     

A Novel Ursane Triterpene from Rubus swinhoei

As a part of investigation on the plant of Rubus, we studied the chemical constituents of the roots of R. swinhoei. A novel ursane triterpene, named swinhoeic acid, was isolated and converted into its methyl-ester with CH2N2. This paper deals with its structure elucidation.Figure 1 The structure of 1 and 1a Figure 2 The key HMBC correlationsCompound 1a, was obtained as white powder, [?] - 66 (c 0.1, CHCl3). Its molecular formula was assigned as C31H48O5 by HR-EIMS ([M]+ m/z 500.3487…     

Determination of the absolute configuration of peptide natural products by using stable isotope labeling and mass spectrometry

Structure elucidation of natural products including the absolute configuration is a complex task that involves different analytical methods like mass spectrometry, NMR spectroscopy, and chemical derivation, which are usually performed after the isolation of the compound of interest. Here, a combination of stable isotope labeling of Photorhabdus and Xenorhabdus strains and their transaminase mutants followed by detailed MS analysis enabled the structure elucidation of novel cyclopeptides named GameXPeptides including their absolute configuration in crude extracts without their actual isolation.     

Elucidating ‘undecipherable’ chemical structures using computer‐assisted structure elucidation approaches

Structure elucidation using 2D NMR data and application of traditional methods of structure elucidation are known to fail for certain problems. In this work, it is shown that computer‐assisted structure elucidation methods are capable of solving such problems. We conclude that it is now impossible to evaluate the capabilities of novel NMR experimental techniques in isolation from expert systems developed for processing fuzzy, incomplete and contradictory information obtained from 2D NMR spectra. Copyright © 2012 John Wiley & Sons, Ltd.     

Antibiotika aus actinomyceten. Isolierung und konstitution von aklavinon—I und aklavinon—II,zwei neuen anthracyclinonen aus fermentationsansätzen von streptomyces galilaeus

The isolation and structure elucidation of two stereoisomers of aklavinone are reported.     

Morierinin: a new cytotoxic cucurbitacin from the leaves of Morierina montana Vieill

An extract of the leaves of Morierina montana collected in New Caledonia was found to be cytotoxic for KB cells. A bioassay-guided fractionation procedure led to the isolation of a series of cucurbitacins of which one, morierinin (1), is new. The isolation and structure elucidation of 1 are described.     

Viscosamine: the first naturally occurring trimeric 3-alkyl pyridinium alkaloid

[structure: see text] Pyridinium alkaloids are widely distributed in marine sponges of different genera. Chemical investigation of the Arctic sponge Haliclona viscosa led to the isolation of a new trimeric 3-alkyl pyridinium alkaloid (viscosamine). Trimers have not been described as natural products yet. The isolation and the structure elucidation of viscosamine are discussed in detail.     

Minor and trace sterols in marine invertebrates 52. isolation,structure elucidation and partial synthesis of 24-propyl-24,28-methylenecholest-5-en-3β-ol

The isolation and structure elucidation of the first cyclopropyl-containing sterol (1) resulting from quadruple bioalkylation of the sterol side chain is reported.     

Stylissadines A and B: the first tetrameric pyrrole-imidazole alkaloids

[reaction: see text] Pyrrole-imidazole alkaloids are widely distributed in marine sponges of the orders Halichondrida and Agelasida. Chemical investigation of the Caribbean sponge Stylissa caribica led to the isolation of the first tetrameric pyrrole-imidazole alkaloids. The so-called stylissadines are the largest and most complex pyrrole-imidazole alkaloids discovered so far and are therefore a major challenge for the structure determination by NMR spectroscopy. Their isolation and structure elucidation are discussed in detail.