领春木枝叶化学成分的研究

为了研究领春木(Euptelea pleiospermum Hook.f.et Thoms)的化学成分,利用各种柱色谱及高压液相色谱等方法进行分离和纯化,根据理化性质和光谱数据分析鉴定了9个化合物。他们分别为:白桦脂酸(1);齐墩果酸(2);N-反式对羟基肉桂酰基-对羟基苯乙胺(3);N-反式阿魏酰酪胺(4);N-顺式阿魏酰酪胺(5);丁香脂素(6);N-顺式阿魏酰-3-甲氧基酪胺(7);N-反式阿魏酰-3-甲氧基酪胺(8);3-羟基-30-去甲基-20-酮基-28-羽扇豆酸(9)。所有化合物均为首次从领春木中分离得到。     

Synthesis of 3-fluoro-6-S-(2-S-pyridyl) nucleosides as potential lead cytostatic agents

The 3-deoxy-3-fluoro-6-S-(2-S-pyridyl)-6-thio-β-d-glucopyranosyl nucleoside analogs 7 were prepared via two facile synthetic routes. Their precursors, 3-fluoro-6-thio-glucopyranosyl nucleosides 5a-e, were obtained by the sequence of deacetylation of 3-deoxy-3-fluoro-β-d-glucopyranosyl nucleosides 2a-e, selective tosylation of the primary OH of 3 and finally treatment with potassium thioacetate. The desired thiolpyridine protected analogs 7a-c,f,g were obtained by the sequence of deacetylation of 5a-c followed by thiopyridinylation and/or condensation of the corresponding heterocyclic bases with the newly synthesized peracetylated 6-S-(2-S-pyridyl) sugar precursor 13, which was obtained via a novel synthetic route from glycosyl donor 12. None of the compounds 6 and 7 showed antiviral activity, but the 5-fluorouracil derivative 7c and particularly the uracil derivative 7b were endowed with an interesting and selective cytostatic action against a variety of murine and human tumor cell cultures.     

Phylogenetic relationships of species in <Emphasis Type="Italic">Pseudoroegneria</Emphasis> (Poaceae: Triticeae) and related genera inferred from nuclear rDNA ITS (internal transcribed spacer) sequences

To evaluate the phylogenetic relationships of species in Pseudoroegneria and related genera, the nuclear ribosomal internal transcribed spacer (ITS) sequences were analyzed for eighteen Pseudoroegneria (St), two Elytrigia (E ^e St), two Douglasdeweya (StP), three Lophopyrum (E ^e and E ^b ), three Agropyron (P), two Hordeum (H), two Australopyrum (W) and two Psathyrostachys (Ns) accessions. The main results were: (i) Pseudoroegneria gracillima, P. stipifolia, P. cognata and P. strigosa (2x) were in one clade, while P. libanotica, P. tauri and P. spicata (2x) were in the other clade, indicating there are the differentiations of St genome among diploid Pseudoroegneria species; (ii) P. geniculata ssp. scythica, P. geniculata ssp. pruinifera, Elytriga caespitosa and Et. caespitosa ssp. nodosa formed the E ^e St clade with 6-bp indel in ITS1 regions; and (iii) Douglasdeweya wangii, D. deweyi, Agropyron cristatum and A. puberulum comprised the P clade. It is unreasonable to treat P. geniculata ssp. scythica and P. geniculata ssp. pruinifera as the subspecies of P. geniculata, and they should be transferred to a new genus Trichopyrum, which consists of species with E ^e St genomes. It is also suggested that one of the diploid donor of D. wangii and D. deweyi is derived from Agropyron species, and it is reasonable to treat tetraploid species with StP genomes into Douglasdeweya.     

Stereoselective reduction of 2-azido-1-phenylethanone derivatives by whole cells of marine-derived fungi applied to synthesis of enantioenriched β-hydroxy-1,2,3-triazoles

Several marine-derived fungi were evaluated by the bioreduction of 2-azido-1-phenylethanone 1, and the strains A. sydowii CBMAI 935 and M. racemosus CBMAI 847 were selected for the reduction of 2-azido-1-phenylethanone derivatives 2–4. Whole cells of A. sydowii CBMAI 935 promoted the reduction of 2-azido-1-phenylethanones 1–4 with high selectivities to yield the (S)-2-azido-1-phenylethanols 1a–4a. Bioreduction of compounds 1–4 by M. racemosus CBMAI 847 led to (R)-2-azido-1-phenylethanols for 1, 2 and 4 and (S)-2-azido-1-phenylethanol 3. Enantiomerically enriched 2-azido-1-phenylethanols 1a–4a and phenylacetylene 5 were applied in the synthesis of β-hydroxy-1,2,3-triazoles using CuSO₄ and sodium ascorbate leading to regioselective formation of enantioenriched 1,4-disubstituted 1,2,3-triazole compounds 1b–4b.     

Comparison of Soybean Tissue Extracted with Different Solvents

The enantioselective hydrolysis of (R,S)-3-acetoxymethyl-7,8-difluoro-2,3-dihydro-4H-[1,4]benzoxazine (I) with enzymes was investigated. Optically active I and its hydrolyzate, 7,8-difluoro-2,3-dihydro-3-hydroxymethyl-4H-[1,4]benzoxazine (II), are the intermediates for preparing optically active ofloxacins, whose racemate is known to be an excellent antibacterial agent. Lipoprotein lipase from Pseudomonas fluorescens (LPL Amano 3) was found to predominantly hydrolyze (S)-I, giving (R)-I in 54% e.e. and (R)-II in 44% e.e. On the other hand, lipase from Candida cylindracea was found to predominantly hydrolyze (R)-I, giving (S)-I in 24% e.e. and (S)-II in 20% e.e. Since, the optical purities of I and II thus obtained were not particularly high, these optically active I and II were converted into 3-acetoxymethyl-7,8-difluoro-2,3-dihydro-4-(3,5-dinitrobenzoyl)-4H-[1,4]benzoxazine (IV). After recrystallizing IV from ethyl acetate-hexane, (S)- and (R)-II were obtained with high enantiomeric excess by removing the crystallized racemic IV and subsequently hydrolyzing the resulting optically active IV with alkali. The reduction of II afforded 7,8-difluoro-2,3-dihydro-3-methyl-4H-[1,4]benzoxazine (III), for which the optical purity was estimated to be >96%e.e. by HPLC analysis. (R)- and (S)-ofloxacin were prepared from (R)- and (S)-III with retention of their configuration.     

Cholinesterase inhibitory triterpenoids from the bark of Garcinia hombroniana

Abstract

Context: Garcinia hombroniana Pierre, known as manggis hutan in Malaysia is a rich source of xanthones and benzophenones.

Objectives: This study was aimed to isolate and characterize potential cholinesterase inhibitors from the extracts of G. hombroniana bark and investigate their interactions with the enzymes.

Materials and methods: The dichloromethane extract afforded five triterpenoids which were characterized by NMR and mass spectral techniques. Cholinesterase inhibitory assay and molecular docking were performed to get insight of the inhibitory activity and molecular interactions of the compounds. The compounds were also tested for their antioxidant capacity.

Results: The isolated triterpenoids were identified as: 2β-hydroxy-3α-O-caffeoyltaraxar-14-en-28-oic acid (1), taraxerol (2), taraxerone (3), betulin (4) and betulinic acid (5). Compound 1 was the most active dual inhibitor of both AChE and BChE. Compound 1 also showed good antioxidant activities.

Conclusion: Compound 1 had dual and moderate inhibitory activity on AChE and BChE worthy for further investigations.     

Adherence ofMycobacterium leprae to the nasal mucosa is influenced by surface integrity and viability

The intranasal route is one of the main routes of Mycobacterium leprae infection and there is paucity of information regarding the mode of spread of the pattern. The adherence of M.leprae to the nasal mucosa, its trapping within the sinuses of the head, and its fate after entry into the host was studied using mouse model. A comparison of the adherence profile of M. leprae and Mycobacterium tuberculosis showed that while larger numbers of M. tuberculosis were demonstrated within lungs, greater numbers of M.leprae were present within the sinuses of the head. Adherence of M.leprae to the nasal mucosa was dependent on surface integrity since opsonization and heat killing resulted in decreased numbers of M.leprae in the nasal sinuses and a greater amount entering the lungs. The adherence appeared to the independent of the viability of the bacilli, as similar numbers of formalin-fixed, rifampicin-treated and viable M.leprae entered the lungs in the initial stages. However the numbers of rifampicin-treated M. leprae in the nasal sinuses were 12-fold lower than the numbers of viable M.leprae. These results indicated that both viability and surface integrity were important in the entry of M.leprae and it’s consequent dissemination.     

α-Hydroxyphosphonate Oligonucleotides: A Promising DNA Type?

Abstract

The synthesis of monomers ( S )-1, ( R )-1 and 2 derived from (5′ S )-, (5′ R )-2′-deoxythymidine-5′-C-phosphonic acids and 2′,5′-dideoxythymidine-5′-C-phosphonic acids was elaborated. The protection of the 5′-hydroxyl by the methoxycarbonyl group was a key step of the synthesis. Prepared monomers were used for the solid-phase assembly of several types oligothymidylate 15-mers ( S )-3, ( S )-4, ( S )-5, ( R )-4 and ( R )-5 containing the chiral 3′-O-P-CH(OH)-5″ internucleotide linkage. Their hybridization properties with dA₁₅ and rA₁₅ were studied as well as their resistance against nuclease cleavage.     

武夷菌素高产基因工程菌株Streptomyces albulus OoWysR活性成分的分离鉴定

【背景】武夷菌素高产基因工程菌株Streptomyce albulus OoWysR具有明显的抑菌效果。【目的】明确S.albulus OoWysR的活性成分。【方法】采用柱层析法,利用大孔吸附树脂、离子交换树脂和高效液相色谱等对S.albulus OoWysR的活性成分进行分离纯化,经高分辨率电喷雾电离质谱(high-resolution electrospray ionization mass spectrometry,HR-ESI-MS)和核磁共振(nuclear magnetic resonance,NMR)等波谱技术对化合物化学结构进行鉴定,并通过生长速率法测定化合物的生物活性。【结果】从S.albulus OoWysR中分离鉴定出4个化合物,分别为对羟基苯甲酸(1)、吡咯-2-羧酸(2)、对羟基苯乙醇(3)和云南霉素(4)。化合物1对玉米弯孢病菌、番茄叶霉病菌、玉米小斑病菌和烟草赤星病菌具有一定的抑制作用;化合物2对番茄灰霉病菌、大豆菌核病菌、苹果腐烂病菌、玉米小斑病菌、小麦赤霉病菌、稻瘟病菌和烟草赤星病菌具有一定的抑制作用;化合物3对番茄灰霉病菌、苹果轮纹病菌、玉米小斑病...     

Community Structure,Geochemical Characteristics and Mineralogy of a Hypersaline Microbial Mat,Cabo Rojo,PR

Seasonal variations in precipitation changed the community composition and microbial activity in a hypersaline, tropical microbial mat, in Cabo Rojo, PR. Using a combination of dissection, light, and transmission electron microscopy, terminal restriction fragment length polymorphism (T-RFLP), in situ microelectrode studies, and ³⁵ S isotope incubations, we documented the major differences between wet and dry seasons. During the wet season (precipitation 177 mm), cyanobacterial (green layer) and anoxyphototrophic (pink layer) communities, as well as the black FeS layer were well-developed, and T-RFLP patterns indicated a diverse community. The rate of oxygenic photosynthesis was 49 μ M min ^{? 1} . Aerobic respiration was 29 μ M min ^{? 1} , and sulfate reduction was 264 nmol cm ^{? 3} h ^{? 1} . During the dry season (precipitation 51 mm), cyanobacteria and anoxyphototrophs were less diverse and abundant, and T-RFLP patterns were less complex. The O ₂ production rate was reduced to 9 μ M min ^{? 1} , as was O ₂ consumption (7 μ M min ^{? 1} ) and sulfate reduction (26 nmol cm ^{? 3} h ^{? 1} ). Aragonite, calcite, halite, and quartz were the predominant minerals. Seasonal differences were found in the green and pink layers for both halite and quartz. Gypsum was not observed, likely due to a sample handling artifact. The fluctuations in community composition and metabolic activity, principally reflected in fluctuations in binding and trapping potential of the uppermost mat community, might be responsible for the observed differences in mineralogy.     

Fatty Acid n-Propyl and Ethyl Esters in the Volatile Oil from Dentcorn,Zea mays L. var. indentata,Silage

(+)-Marmelo Lactones A(VA) and B (VB) were synthesized from erythro-γ-methyl-l-glutamic acid (IA) and threo acid (IB), respectively. The absolute configurations of natural marmelo lactones were thus determined to be (2R, 4S) for (+)-marmelo lactone A and (2R, 4R) for ( – )-marmelo lactone B.     

Limonoids from the fruits of Melia toosendan

Four (1–4) new and seven known limonoids were isolated from the EtOH extract of the fruits of Melia toosendan. The structures of the new compounds were established on the basis of spectroscopic methods to be 12-O-methyl-1-O-deacetylnimbolinin B (1), 12-O-methy-1-O-tigloyl-1-O-deacetylnimbolinin B (2), 12-O-ethylnimbolinin B (3), and 1-O-cinnamoyl-1-O-debenzoylohchinal (4). Additionally, two new tirucallane-type triterpenoids, named meliasenins S (5) and T (6), were obtained from the same fractions during purification of the limonoids.     

Calpain inhibitory flavonoids isolated from Orostachys japonicus

The n-butanol (n-BuOH) fraction of Orostachys japonicus A. Berger (Crassulaceae) significantly inhibited calpain activity. Through the activity-guided isolation from the n-BuOH fraction, herbacetin 8-O-α-D-ribopyranoside (1), kaempferol (2), quercetin (3), afzelin (4), astragalin (5), isoquercetin (6) and quercitrin (7) were obtained. Their structures were determined by spectroscopic techniques. Among them, compound 3 and 5 had significant calpain inhibitory activities.     

Constituents with tyrosinase inhibitory activities from branches of Ficus erecta var. sieboldii King

Phytochemical investigation of the branches of Ficus erecta var. sieboldii King resulted in the isolation of eight constituents: p-hydroxybenzoic acid (1), methyl p-hydroxybenzoate (2), vanillic acid (3), methyl vanillate (4), syringic acid (5), β-sitosterol (6), α-amyrin acetate (7), and ethyl linoleate (8). Their chemical structures were identified via spectroscopic means as well as by comparing their data with literature values. Studies on tyrosinase inhibition activities were conducted for the isolated compounds. Among them, p-hydroxybenzoic acid (1) and methyl p-hydroxybenzoate (2) were identified as active tyrosinase inhibitors with IC₅₀ values of 0.98?±?0.042 and 0.66?±?0.025?mM, respectively, showing comparable activities to that of arbutin (IC₅₀?=?0.32?±?0.015?mM), a standard control. Inhibition kinetics, as analyzed by Lineweaver-Burk plots, indicated that compounds 1 and 2 were competitive inhibitors of diphenolase of mushroom tyrosinase. Notably, isolated compounds 1–8 were reported for the first time as constituents of F. erecta.     

Synthesis and Biological Evaluation of 9-(f-2, c-3-Bishydroxymethyl-r-cyclopropylmethyl)-9H-adenine (A Lower Methylene Homolog of Carbocyclic Oxetanocin) and Related Compounds

Abstract

Adenine (7 and 16), thymine (9a and 18a), and 5-fluorouracil (9b and 18b) involving f-2, c-3-bishydroxymethyl-r-1-cyclopropylmethyl- and t-2 t-3-bishydroxymethyl-r-1-cyclopropylmethyl residues were synthesized, starting from trans-1, 4-dibenzyloxy-2-butene and its cis isomer, respectively. These compounds were evaluated for anti HSV-1 activity.     

白花鬼针草中多烯炔类成分的分离及其生物活性研究

为了解白花鬼针草(Bidens pilosa var.radiata)的化学成分,采用多种色谱技术从其提取物中分离多烯炔类成分,并对其生物活性进行研究。结果表明,从白花鬼针草乙酸乙酯提取部位中分离鉴定出4个多烯炔类化合物,分别为5-acetoxy-2-phenylethinyl-thiophene (1)、1-phenylhepta-1,3,5-triyne (2)、5-phenyl-2-(1-propynyl)-thiophene (3)和icthyothereol acetate (4)。体外活性评价结果表明,化合物1～4均具有中等抗MRSA活性,且均对人肝LO_2细胞无毒性。首次为化合物1提供核磁数据并进行结构解析,化合物3、4为首次从该属植物中分离得到。     

Reaction of Astaxanthin with Peroxynitrite

The in vitro reactivities of astaxanthin toward peroxynitrite were investigated and the reaction products after scavenging with peroxynitrite were analyzed in order to determine the complete mechanism of this reaction. A series of carotenoids, 13-apo-astaxanthinone (1), 12′-apo-15′-nitroastaxanthinal (2), 12′-apo-astaxanthinal (3), 10′-apo-astaxanthinal (4), 9-cis-14′-s-cis-15′-nitroastaxanthin (5), 14′-s-cis-15′-nitroastaxanthin (6), 13-cis-14′-s-cis-15′-nitroastaxanthin (7), 10′-s-cis-11′-cis-11′-nitroastaxanthin (8), 13,15,13′-tri-cis-15′-nitroastaxanthin (9), 9-cis-astaxanthin (10), and 13-cis-astaxanthin (11), were isolated from the reaction products of carotenoids with peroxynitrite. Our previous studies achieved for the first time the isolation of nitro derivatives from the reaction of astaxanthin with peroxynitrite. Here we identify the major remaining reaction products of this reaction and investigate the stabilities of the nitro astaxanthins.     

Hydroxylation of (+)-menthol by Macrophomina phaseolina

Abstract

Biotransformation of (+)-menthol with Macrophomina phaseolina led to hydroxylations at C-1, C-2, C-6, C-7, C-8 and C-9, with the C-8 position being preferentially oxidized. The resulting metabolites were identified as 8-hydroxymenthol (2), 6R-hydroxymenthol (3), 1R-hydroxymenthol (4), 9-hydroxymenthol (5), 2R,8-dihydroxymenthol (6), 8S,9-dihydroxymenthol (7), 6R,8-dihydroxymenthol (8), 1R,8-dihydroxymenthol (9) and 7,8-dihydroxymenthol (10). Metabolites 6–10 are described here for the first time. Their structures were characterized by spectroscopic analysis.     

黄皮果皮中的抗菌活性成分研究

为了解黄皮[Clausena lansium(Lour.)Skeels]果皮中的抗菌活性成分,采用硅胶柱色谱、Sephadex LH-20凝胶柱色谱等方法,从黄皮果皮的乙醇提取物中分离得到10个化合物,经波谱学分析鉴定为:lansine(1)、3-甲酰基咔唑(2)、3-甲酰基-6-甲氧基咔唑(3)、6-甲氧基咔唑-3-羧酸甲酯(4)、(6R,7E,9S)-9-羟基-4,7-巨豆二烯-3-酮(5)、7-羟基香豆素(6)、8-羟基呋喃香豆素(7)、辛黄皮酰胺(8)、对羟基肉桂酸甲酯(9)和胡萝卜苷(10)。其中化合物5和9为首次从黄皮属植物中分离得到,化合物8的碳谱数据是首次报道。用滤纸片琼脂扩散法测定化合物的抗菌活性,结果表明,化合物1、2、3、6、7和9对金黄色葡萄球菌(Staphylococcus aureus)有抑制作用。这有利于更好地开发利用黄皮这一药食两用的水果资源。     

A Rennin-like Enzyme from Penicillium expansum

dl-(1,3/2)-3-Acetamido-1,2-di-O-benzylcyclohex-4-enediol (IIIa) and dl-(1,3/4)-1-acetamido-3,4-di-O-benzylcyclohex-5-enediol (IIIb) were synthesized from dl-trans-1,2-di-O-benzylcyclohex-3-enediol (I) via the corresponding azide derivatives (IIa-b) prepared by bromination and subsequent treatment with sodium azide in N,N-dimethylformamide. Compounds (IIIa and IIIb) were converted into a variety of deoxyinosamine and deoxyinosadiamine derivatives via epoxides (VIII and IX) or by cis-hydroxylation with osmium tetroxide. Hexaacetyl-rac-inosamine-1 (XVIIIc) was synthesized from dl-(1,3,4/2,5)-3-acetamido-1,2-di-O-benzyl-5-bromocyclohexanetriol (VIa) via conduramine derivatives (XVIIa-c). Conformationai analysis of partially O-benzylated aminocyclitol derivatives were studied by means of NMR spectroscopy.