Isolation and purification of inflacoumarin A and licochalcone A from licorice by high-speed counter-current chromatography

High-speed counter-current chromatography (HSCCC) technique in semi-preparative scale has been applied to isolate and purify bioactive flavone compounds from the ethanol extract of Glycyrrhiza inflata Bat., a particular plant species of licorice. HSCCC separation was performed with a two-phase solvent system composed of n-hexane-chloroform-methanol-water (5:6:3:2, v/v) by eluting the lower mobile phase at a flow rate of 1.8 ml/min and a revolution speed of 800 rpm. Purification was performed with a two-phase solvent system composed of n-hexane-chloroform-methanol-water (1.5:6:3:2, v/v) by eluting the lower mobile phase at a flow-rate of 1.5 ml/min and a revolution speed of 800 rpm. Two major flavone peaks: inflacoumarin A and licochalcone A were collected and the respective yields of the peaks amount to 6 mg (8.6%, w/w) and 8 mg (11.4%, w/w) from 70 mg of the crude extract sample. The purities of inflacoumarin A and licochalcone A reached 99.6% and 99.1%, respectively, after a sequential purification run. The structures of inflacoumarin A and licochalcone A were positively confirmed by 1H NMR and 13C NMR, 1H-13C-COSY, UV, FT-IR and electron ionization MS analyses.     

Synthesis of Arcyriarubin A and Arcyriaflavin A via Cross-Coupling of Indolylboronic Acid with Dibromomaleimides

Arcyriarubin A was first isolated by Steglich in 1980; it is also the key intermediate in the synthesis of indolocarbazole compounds. A new synthetic approach to the natural products arcyriaflavin A and arcyriarubin A is described. The key step is a Suzuki cross-coupling reaction using indolylboronic acid as the starting material. The preparation of arcyriaflavin A was accomplished in eight steps from indole for a total yield of 21%.     

抗HIV天然产物Calanolide A及其类似物的合成进展

Calanolide A是从藤黄科红厚壳属植物(Calophyllum lanigerum)中分离的一种吡喃型香豆素类化合物, 对HIV-1- RT有很强的抑制作用, 是目前抗HIV的热点先导物. 综述了该化合物及其类似物的全合成研究进展, 分析了它的合成路线, 讨论了各合成方法的优缺点.     

Hirsutellide A立体异构体的单晶结构与抗分支杆菌生物活性研究

研究了hirsutellide A立体异构体的X衍射单晶结构及其抗分支杆菌活性. 该化合物具有扭曲马鞍型18元大环结构; 在体外生物活性测试中, 化合物未表现出明显的抗分支杆菌活性. 由实验结果可以看出在天然环酯肽hirsutellide A中3'-C手性中心是其生物活性关键位点之一.     

One Step of Palladium Catalyzed Benzodioxane Ring C–O Bond Formation,Synthesis of Isoamericanol A and Isoamericanin A

Abstract

A number of benzodioxane compounds were synthesized using the palladium‐catalyzed etherification of aryl halides by employing triphenylphosphane ligands. This method was used as key step in the synthesis of two natural products isoamericanol A and isoamericanin A.     

Assignment of the absolute configuration of blasticidin A and revision of that of aflastatin A

The absolute configuration of blasticidin A, a strong inhibitor of aflatoxin production by Aspergillus parasiticus, was assigned by adding the data of relative configurations at its diol and pentaol moieties to previously known stereochemistry. Similarity of the NMR data of blasticidin A to those of aflastatin A allowed us to revise the stereochemistry of the diol and pentaol moieties of aflastatin A.     

Facile Synthesis of Isoamericanol and Isoamericanin A

A number of benzodioxane compounds were synthesized using the palladium-catalyzed etherification of aryl halides by employing triphenylphosphane ligands. This method was used as key step in the synthesis of isoamericanol A and isoamericanin A.     

Brij35增敏荧光法测定塑料饮料瓶中双酚A

建立了测定塑料饮料瓶中双酚A的Brij35增敏荧光分析法.实验考察了不同介质及pH、静置时间、介质用量、金属离子等因素对双酚A(BPA)荧光强度的影响.结果表明,在所探讨的7种介质中Brij 35荧光增敏效果最好,据此建立了一种用Brij35增敏荧光光度法测定双酚A的新方法.方法线性范围为2.0×10-8～1.0×10-5 mol/L,检出限为2.5×10-8 mol/L,相对标准偏差为1.92％.该方法快速、简便、灵敏度高,对实际样品塑料饮料瓶中双酚A的检测,结果满意.     

Synthesis of plakevulin A and structure-activity relationships of its related compounds against DNA polymerases

Synthesis of plakevulin A and structure-activity relationships of its related compounds against DNA polymerases is described. We have achieved a total synthesis and revised the structure of plakevulin A. Several analogues including untenone A, manzamenone A, and optically active plakevulin A, were prepared and tested with an enzyme inhibition assay for mammalian DNA polymerases. The effect of the methyl ester moiety, and the substituents at the 1- and 4-positions of plakevulin A on DNA polymerase activities are discussed.     

红树林内生真菌Paecilomyces sp.(tree1-7)次级代谢产物及其活性研究

近年来海洋微生物作为许多活性次级代谢的源泉而受到世界范围内的天然产物和药理学家的广泛关注[1],特别是来自海洋真菌的次级代谢产物具有巨大的潜力,因为其次级代谢产物往往具有新颖的骨架[2].我们实验小组已从中国南海红树林内生真菌的次级代谢产物中分离到大量新颖的有活性结构的化合物[3-5].     

Sansalvamide A固相合成新方法

报道了Pd催化丁基二乙基硅烷树脂与N-Boc-4-溴代苯丙氨酸甲酯直接反应形成Si—Ar键一步构建出硅基连接分子的新方法, 并采用Boc策略增长肽链, 以PyBOP (benzotriazole-1-yl-oxy-tris-pyrrolidino-phosphonium hexafluoro- phosphate)为环合剂固相合成了sansalvamide A.     

Total Synthesis,Absolute Configuration,and Biological Activity of Xyloallenoide A

The novel natural product xyloallenoide A, isolated from the marine mangrove endophytic fungus from the South China Sea, and its diastereoisomer xyloallenoide A1, which contain N‐methyl‐substituted amino acids, were synthesized. The absolute configurations of the amino acid units of xyloallenoide A were finally confirmed to be L ‐Lys, Me‐D ‐Val, and Me‐L ‐Ala. This report represents a practical and attractive alternative for the synthesis of N‐methyl‐substituted cyclotripeptides. In the preliminary bioassay, synthetic xyloallenoide A showed marginal activities against KB (IC₅₀=9.6 μM ) and KBv200 cells (IC₅₀=10.3 μM ), and xyloallenoide A1 was inactive against KB and KBv200 cells.     

New Dopamine Derivative from Lycium Barbarum

Incontinuationofourworkoncyclicpeptidesandamides'-',wetestedextractsofthefruitsofLyciumbarbarumwhichwasusedasatonicandsedativeintraditionalChinesemedicineandfoundtheextractscontainedconstituentwhichshowedpositivereactionwithninhydrinafterhydrolysis.ThusweinvestigatedtheplantandanewdopaminederivativeInamedlyciumideAwasisolated.Figure1.ThestructureoflyciumideAIJLyciumideAIwasobtainedascolorlessgum.Itcouldbededucedasanamidesincethecompoundshowednegativereactionwithninhydrinbutpositiveafterhyd…     

Efficient synthetic method of Psammaplin A

A new concise and efficient synthetic method of Psammaplin A was developed. Psammaplin A was obtained with 50% overall yield in nine steps from p-hydroxybenzaldehyde and ethyl acetoacetate via Knoevenagel condensation and direct nitrosation as key steps. This method might be very efficient to construct a quite diverse library of Psammaplin A type analogs.     

A Novel Compound From Ceratostigma Minus

PreviouspaPershavereportedtheisoIationofseveralcompounds,plumbasidesA-C,plumbagin,quercetin,myricetin,quercetin3-O-glucoside,myricetin3-O-rhamnosideandmaltol-O-glucosidefromCeratostigmaminusl'2.Thecontinuationofourresearchworkforbioactivecompoundshaveledtotheisolationofanovelcompound,plumbocatechinA1.Thestructureelucidationof1weremadeby2D-NMRtechniques.PlumbocatechinA1wasobtainedasanamorPhouspowder-EIMSclearlyrevealedthemolecularweighttobe346andHREIMSestablisheditselementalformulaasC…     

Analysis of the Composition of Lyophilisates Obtained from Aloe arborescens Gel of Leaves of Different Ages from Controlled Crops

The aim of the study is to evaluate the composition of lyophilisates obtained from Aloe arborescens leaf gel at the age of one to four years. The leaves were obtained from controlled crops, which allowed to exclude environmental factors as variables. It was confirmed that the lyophilisates obtained from different years of Aloe arborescens leaf gel varied in chromatographic analyses in terms of aloin A and aloenin A content (high-performance liquid chromatography with diode-array detection HPLC-DAD, high-performance liquid chromatography with tandem mass spectrometric detection HPLC-MS/MS). Similarly, while testing the phenolic acids and the sum of polyphenols content, differences in their levels in leaf gel lyophilisates from plants of individual years were observed (spectrophotometric method UV-VIS). The lyophilisate composition analysis showed that the one-year-old leaves were characterized by the highest content of aloin A and aloenin A. While the content of polyphenols, including phenolic acids, was higher in the leaves of older plants. The antioxidant potential of the tested lyophilisates was assessed simultaneously. Regardless of the research model used (CUPRAC, DPPH, ABTS), an antioxidant effect was noted for Aloe arborescens leaves.     

4-叔丁氧羰酰胺基-呋喃-2-甲酸甲酯的合成

以呋喃甲醛为起始原料,经过5步反应合成了天然产物Proximicin A的     

苷类研究ⅩⅩⅥ: 苯丙素苷Eutigoside A的合成研究

首次报道了苯丙素苷类化合物EutigosideA,即1-O-[2-(4-羟基苯基)乙基]-6-O-(E)-香豆酰基-β-D-吡喃葡萄糖的全合成。从四乙酰溴代葡萄糖出发,经过成苷、脱乙酰基两步反应,制备了2-对烯丙氧基苯基-β-D-吡喃葡萄糖苷(3),采用酰氯法在低温下将对乙酰氧基肉桂酰基引入化合物3的葡萄糖6位,再经过脱烯丙基、脱乙酰基两步,便顺利地合成了天然苯丙素苷EutigosideA。以化合物3为原料,经过对葡萄糖4,6位亚苄基化、2,3位乙酰化、4,6位脱亚苄基、选择性6位乙酰化及4位引入对乙酰氧基肉桂酰基等五步反应,得到了保护的苯丙素苷(OsmanthusideA(10);但在NH~3/MeOH条件下脱乙酰基时,化合物10中的香豆酰基从葡萄糖的4位迁移至6位,最终又得到了EutigosideA。     

Structure Revision of Caesalpinistas A and B and Isolation of a New Furanoditerpenoid from the Cotyledons of Caesalpinia decapetala var. japonica

A known cassane‐type furanoditerpenoid, caesalpinista B ( 1 ), and a new diterpenoid, deoxycaesaljaponin A ( 2 ), were isolated from the cotyledons of Caesalpinia decapetala var. japonica. The previously reported configurational assignments of 1 and the related diterpenoid caesalpinista A ( 3 ) were revised on the basis of X‐ray crystallography and chemical conversion. The structure of 2 was elucidated by spectroscopic data and chemical conversion into 3 .     

Chemical synthesis and firefly luciferase produced dehydroluciferyl-coenzyme A

Dehydroluciferyl-coenzyme A (L-CoA) was chemically synthesized and characterized by MS, UV-vis spectrometry and RP-HPLC. The identity of the chemically synthesized compound with the one that was produced by firefly luciferase was confirmed. Moreover, the reversibility of the enzymatic conversion of dehydroluciferin ? dehydroluciferyl-adenylate ? L-CoA was also confirmed. The chemical synthesis of L-CoA, described here, may help the clarification of the activator effect of CoA on luciferase bioluminescent assays, in which the enzyme catalyzed formation of L-CoA and the consequent destruction of L-AMP is one of the possible explanations for that effect.