柔荑软珊瑚Nephthea sp.中两种具有细胞毒活性的甾醇化合物

采用抗肿瘤活性追踪法对采自中国南海西沙群岛永兴岛柔荑软珊瑚Nephthea sp.中抗肿瘤活性成分进行研究, 报道了两种具有细胞毒活性的甾醇化合物, 经过MS, IR, ¹H NMR, ¹³C NMR (DEPT), HSQC 和HMBC等光谱技术鉴定为: 24-甲基胆甾-5-烯-3β,8β-二醇(1)和24-亚甲基胆甾-4-烯-3β,6β-二醇(2), 化合物1为新化合物, 利用X-ray单晶衍射技术验证化合物2的立体结构. 化合物1对肝癌细胞(BEL-7402), 小鼠白血瘤细胞(P₃₈₈)和人结肠癌细胞(LOVO)作用的IC₅₀值分别为18.0, 25.5和20.6 μg/mL; 化合物2对肿瘤细胞P₃₈₈和人乳腺癌细胞(MCF)作用的IC₅₀值分别为1.0和2.5 μg/mL.     

海洋放线菌Streptomyces sp.124092中的细胞毒活性成分

对海洋放线菌Streptomyces sp.发酵液的提取物进行柱层析分离, 得到5个化合物. 经MS, NMR, 1H-1H COSY, HSQC和HMBC等数据鉴定, 其结构分别为3-氨基-丙酸对甲苯酯(1)、6-Amino-3-(4-hydroxybenzyl)-1,4-diazonane-2,5-dione(2)、正丁基-α-D-吡喃甘露糖苷(3)、大豆苷元(4)和1H-3-吲哚甲酸(5). 其中化合物1和2为新化合物, 细胞毒活性测试结果表明, 化合物1~4对人肝癌细胞(SMMC-7721)具有不同程度的生长抑制活性.     

D-谷氨酰胺的制备

报道了以化学合成和生物转化的方法制备光学纯D-谷氨酰胺. 首先在中试规模上用化学方法合成DL-谷氨酰胺. 即以廉价的DL-谷氨酸为原料, 采用邻苯二甲酰基作为保护基保护L-谷氨酸的α-氨基, 醋酐回流15 min, 使其分子内脱水生成N-邻苯二甲酰-DL-谷氨酸酐, 在常温、常压条件下, 分别与2 mol/L氨水反应生成中间产物N-邻苯二甲酰-DL-谷氨酰胺, 中间产物在室温条件下与0.5 mol/L水合肼反应48 h脱除保护基, 以57%总收率得到DL-谷氨酰胺. 在37 ℃, pH 4.8的条件下, 利用大肠杆菌(E. coli. AS 1.505)脱羧酶将底物浓度30 g/L的DL-谷氨酰胺中L型对映体在8 h内完全转化为4-氨基丁酰胺, 分离得到D-谷氨酰胺.     

三个新的海绵Spongia suriganensis神经酰胺

报道从中国南海硇洲岛产海绵Spongia suriganensis的乙醇浸提物中分离得到3个新的同系列神经酰胺2-N-(1,3,4-三羟基-17-甲基)十八烷基-2'-羟基-18-甲基二十碳酰胺(1), 2-N-(1,3,4-三羟基-17-甲基)十八烷基-2'-羟基-19-甲基二十一碳酰胺(2)和2-N-(1,3,4-三羟基-17-甲基)十八烷基-2'-羟基-20-甲基二十二碳酰胺(3), 其结构经过MS, IR, ¹H NMR, ¹³C NMR (DEPT), HMQC及HMBC等现代光谱手段和水解化学方法来确定.     

中国南海裸鳃目软体动物美丽拟皮片鳃(Dermatobranchus orna-tus)及其可能的食源动物柳珊瑚Muricella sp.的化学成分研究

从中国南海的裸鳃目软体动物美丽拟皮片鳃(Dermatobranchus ornatus)中分离得到4个eunicellane型二萜: Ophirin (1), calicophirin B (2), 13-去乙酰氧基 calicophirin B (3)及3-去乙酰基-13-去乙酰氧基calicophirin B (4); 而由同时、同地采集到的柳珊瑚Muricella sp. 中则分离得到calicophirin B (2), 13-去乙酰氧基 calicophirin B (3), astrogorgin (5) 及类似物6. 这些化合物的结构经波谱学实验并与文献报道的数据相对照得以确定, 并首次对Ophirin (1) 的NMR数据进行了全归属. Ophirin (1) 的单晶X衍射实验不但进一步确证了化合物的结构, 而且使这一类化合物的立体结构表述得到修正. 本文是对Dermatobranchus属软体动物化学成分研究的首次报道; 研究提示, 美丽拟皮片鳃能通过选择适当的食物, 并将食物中有用的次生代谢产物转移、富集到身体的特定部位, 使之成为自身的化学防性物质. 美丽拟皮片鳃与Muricella 属柳珊瑚中共同出现的类似化合物支持二者间可能存在的捕食与被捕食的生态学关系.     

多羟基甾醇25(R)-异螺甾环-5-烯-2β,3α,19-三醇的合成

以薯蓣皂素为原料, 经过磺酰酯化、N-溴代丁二酰亚胺(NBS)氧化加成、Pb(OAc)₄远程氧化关环、消去反应、间氯过氧苯甲酸(mCPBA)氧化、高氯酸开环及锌粉还原7步反应, 合成多羟基甾体25(R)-异螺甾环-5-烯-2β,3α,19-三醇. 并用IR, ¹H NMR, ¹³C NMR, MS及元素分析对各中间体及目标化合物进行了表征.     

手性β-氨基醇催化α,β-不饱和酮的不对称环氧化反应

将以烯烃为原料通过Sharpless不对称双羟化等多步反应合成的8种手性β-氨基醇, 作为有机小分子催化剂, 用于催化α,β-不饱和酮的不对称环氧化反应．考察了影响对映选择性的催化剂结构、催化剂用量、氧化剂种类、溶剂、反应温度等因素．结果表明, 当催化剂用量为30 mol%、氧化剂为TBHP(叔丁基过氧化氢)、正己烷溶剂、在室温下、以(1S,2R)-(＋)-1,2-二苯基-2-甲氨基乙醇(3)作催化剂时, 所得环氧化物的对映体过量最高为70% ee, 产率最高为84%.     

红树尖瓣海莲内生真菌Penicillium sp.J41221的代谢产物及其抗菌活性研究

在生物活性指导下,从一株来源于药用红树尖瓣海莲的内生真菌Penicillium sp.(J41221)中分离鉴定了6个化合物,包括4个四环三萜类化合物和2个甾醇类化合物,结构分别为:11-羰基-12α-乙酰氧基-4,4-二甲基-24-甲烯基-5α-胆甾-8,14-二烯-2α,3β-二醇(1),12α-乙酰氧基-4,4-二甲基-24-甲烯基-5α-胆甾-8-单烯-3β,11β-二醇(2),12α-乙酰氧基-4,4-二甲基-24-甲烯基-5α-胆甾-8,14-二烯-3β,11β-二醇(3),12α-乙酰氧基-4,4-二甲基-24-甲烯基-5α-胆甾-8,14-二烯-2α,3β,11β-三醇(4),啤酒甾醇(5)和(3β,5α,6β,22E)-6-甲氧基麦角甾-7,22-二烯-3,5-二醇(6).其中化合物1为首次从生物中获得,且1和2的波谱数据迄今未见任何报道.抗菌活性结果表明,化合物2和4对金黄色葡萄球菌、大肠杆菌和四联球菌均显示一定的抑制活性,最小抑菌浓度(MIC)分别为5和4.86μmol/L.     

六～八元瓜环与三种N-苄基取代笼状客体的相互作用

合成了3种具有对不同瓜环选择性各异的双探针N-苄基取代笼状客体, 它们分别是N-苄基六次甲基四胺盐酸盐(1), N-苄基喹啉环啶盐酸盐(2), N-苄基-1,4-二氮杂双环[2.2.1]辛烷盐酸盐(3), 利用¹H NMR和MS等方法对这些客体进行了表征. ¹H NMR显示, 六元瓜环仅对这些客体的苄基探针部分具有选择性作用, 形成作用比为1∶1的不对称包结配合物; 七元瓜环对客体1和3的苄基探针部分具有选择性作用, 形成作用比为1∶1的不对称包结配合物, 而对客体2的笼状奎宁环啶基部分具有选择性作用, 也形成作用比为1∶1的包结配合物; 八元瓜环也仅对这些客体的苄基探针部分具有选择性作用, 形成作用比为1∶2的对称包结配合物.     

2-(N'-乙基咔唑-3'-烯基)-8-羟基喹啉的合成及理论研究

设计合成了2-(N'-乙基咔唑-3'-烯基)-8-羟基喹啉. 以UV-Vis, ¹H NMR, FT-IR, 元素分析和MS进行了结构表征, 并测定了产物的光致发光(PL)性质. 运用Gaussian98量子化学程序包, 采用B3LYP密度泛函(DFT)的方法, 在6-31G(d,p)水平上对分子的几何构型进行结构优化; 预测目标产物的振动光谱, 结果表明与实验值相符.     

Novel Polyketides Isolated from Streptomyces sp.

From the endophytic strain Streptomyces sp. CS of Maytenus hookeri, five novel type III polyketides, compounds 1 – 5 , were isolated. Their structures were elucidated by spectroscopic analyses including 1D‐ and 2D‐NMR experiments, and by HR‐ESI‐MS.     

A Novel Oxidative N-Demethylation of 12-Membered Macrolide with Lead Tetraacetate

Erythromycin has been extensively used in the treatment of bacterial infections for over 50 years1. In addition to the antimicrobial effect, the quite unique antiinflammatory activity of the erythromycin derivatives has attracted much attention as new the…     

A new diketopiperazine derivative from a deep sea-derived Streptomyces sp. SCSIO 04496

A new diketopiperazine (DKP) derivative, (6R,3Z)-3-benzylidene-6-isobutyl-1-methyl piperazine-2,5-dione (1), as well as five known DKPs 2–6 was isolated from a deep sea-derived Streptomyces sp. SCSIO 04496. The structure of 1 was elucidated using a combination of 1D and 2D NMR, HR-ESI-MS and chiral-phase HPLC techniques. Compounds 1–6 did not show cytotoxic activity at a concentration of 100 μM in bioactivity assay.     

Purification and Characterization of Novel Anti-MRSA Peptides Produced by Brevibacillus sp. SPR-20

Methicillin-resistant Staphylococcus aureus (MRSA) is listed as a high-priority pathogen because its infection is associated with a high mortality rate. It is urgent to search for new agents to treat such an infection. Our previous study isolated a soil bacterium (Brevibacillus sp. SPR-20), showing the highest antimicrobial activity against S. aureus TISTR 517 and MRSA strains. The present study aimed to purify and characterize anti-MRSA substances produced by SPR-20. The result showed that five active substances (P1–P5) were found, and they were identified by LC-MS/MS that provided the peptide sequences of 14–15 residues. Circular dichroism showed that all peptides contained β-strand and disordered conformations as the major secondary structures. Only P1–P4 adopted more α-helix conformations when incubated with 50 mM SDS. These anti-MRSA peptides could inhibit S. aureus and MRSA in concentrations of 2–32 μg/mL. P1 (NH₂-VVVNVLVKVLPPPVV-COOH) had the highest activity and was identified as a novel antimicrobial peptide (AMP). The stability study revealed that P1 was stable in response to temperature, proteolytic enzymes, surfactant, and pH. The electron micrograph showed that P1 induced bacterial membrane damage when treated at 1× MIC in the first hour of incubation. The killing kinetics of P1 was dependent on concentration and time. Mechanisms of P1 on tested pathogens involved membrane permeability, leakage of genetic material, and cell lysis. The P1 peptide at a concentration up to 32 μg/mL showed hemolysis of less than 10%, supporting its safety for human erythrocytes. This study provides promising anti-MRSA peptides that might be developed for effective antibiotics in the post-antibiotic era.     

Novel cyclohexene and benzamide derivatives from marine-associated Streptomyces sp. ZZ502

Three new compounds and the known benzamides of 2-acetamido-3-hydroxybenzamide, 2-amino-3-hydroxybenzamide, and 2-aminobenzamide were isolated from the culture of a marine actinomycete Streptomyces sp. ZZ502. Structures of the new compounds were determined as 3-amino-2-carboxamine-6(R)-chloro-4(R),5(S)-dihydroxy-cyclohex-2-en-1-one, 3-amino-2-carboxamine-4(S),6(S)-dihydroxy-cyclohex-2-en-1-one, and 3-hydroxy-2-propionamidobenzamide based on extensive NMR spectroscopical analysis, HRESIMS data, ECD calculation, and X-ray diffraction analysis. None of these isolated compounds showed activity in inhibiting the proliferation of glioma cells nor the growth of methicillin-resistant Staphylococcus aureus, Escherichia coli, and Candida albicans.     

Microbial transformation of resveratrol by endophyte Streptomyces sp. A12 isolated from Polygonum cuspidatum

Resveratrol (1) undergoes microbial transformation when fermented with Streptomyces sp. A12 to yield 3, 5, 4′-trimethoxy-trans-stilbene (2). The structure of the compound 2 was elucidated using the modern spectroscopic techniques. This is the first report of the microbial transformation of resveratrol to compound 2 using the endophyte isolated from Polygonum cuspidatum.     

A rare diketopiperazine glycoside from marine-sourced Streptomyces sp. ZZ446

Abstract

Two diketopiperazines were isolated from a culture of the marine-derived actinomycete Streptomyces sp. ZZ446. Their structures were elucidated as maculosin (1) and maculosin-O-α-L-rhamnopyranoside (2) based on their NMR and HRESIMS data, specific rotation, and chemical degradation. Maculosin-O-α-L-rhamnopyranoside (2) is a new diketopiperazine glycoside, a structural class not reported previously from the natural sources. Both compounds showed antimicrobial activity against methicillin-resistant Staphylococcus aureus, Escherichia coli, and Candida albicans with MIC values in a range from 26.0 to 37.0?μg/mL.

     

A New Virginae Butanolide from Streptomyces sp.

A novel butanolide, named virginaebutanolide F (1), was isolated from the lyophilized culture broth of Slreptomyces sp., along with a known compound virginaebutanolide C (2). Their structures including the stereochemistry were elucidated on the basis of extensive 1D and 2D NMR as well as HRESI-MS and CD spectroscopic analysis.     

Angucycline antibiotics and its derivatives from marine-derived actinomycete Streptomyces sp. A6H

Vineomycin A₁ (1) and B₂ (2) were isolated from the culture broth of marine actinomycete Streptomyces sp. A6H. Five hydrolysis products were obtained by rational hydrolysis and methanolysis of the fermentation extract. Their structures were characterised as aquayamycin (3), vineomycinone B₂ (4), 9-C-_D-olivosyltetrangulol (5), 7-O-methylgaltamycinone (6) and vineomycinone B₂ methyl ester (7). In addition to these compounds, two ester derivatives, vineolactone A (8) and vineomycinone B₂ benzyl ester (9) of compound 4 were generated semisynthetically. Compound 6 is a new analogue of galtamycinone, while compounds 8 and 9 are new members of vineomycins. Cytotoxic activities and antimicrobial activities were determined for all compounds. The results indicate that only compound 1 showed significant activities with IC₅₀ value of 0.34 μM against H1975 and MIC value of 4 μg/mL against Staphylococcus aureus.     

Four new anthraquinones from a soil actinomycete Streptomyces sp. WS-13394 and their bioactivities

Further chemical study of secondary metabolites from the soil actinomycete Streptomyces sp. WS-13394 resulted in the isolation of four new alkylated anthraquinone analogues (5–8). Their structures were elucidated on the basis of extensive spectroscopic analysis, including HR-ESI-MS, 1D and 2D NMR. The new compounds, together with analogues obtained before (1–4), were tested for their in vitro cytotoxicity against Huh-7 and SGC-7901.