Synthesis and bioactivity of 5-(1-aryl-1H-tetrazol-5-ylsulfanylmethyl)-N-xylopyranosyl-1,3,4-oxa(thia)diazol-2-amines

A series of new N′-[N-(2,3,4-tri-O-acetyl-β-d-xylopyranosyl)thiocarbamoyl]-2-[(1-aryl-1H-tetrazol-5-yl)sulfanyl]acetohydrazides 5a–5e were synthesized rapidly in high yields from 2-(1-aryl-1H-tetrazol-5-ylsulfanyl)acetohydrazides 3a–3e and 2,3,4-tri-O-acetyl-β-d-xylopyranosyl isothiocyanate 4, then 5a–5e were converted to a series of new 5-(1-aryl-1H-tetrazol-5-ylsulfanylmethyl)-N-(2,3,4-tri-O-acetyl-β-d-xylopyranosyl)-1,3,4-oxadiazole-2-amines 6a–6e and 5-(1-aryl-1H-tetrazol-5-ylsulfanylmethyl)-N-(2,3,4-tri-O-acetyl-β-d-xylopyranosyl)-1,3,4-thiadiazole-2-amines 7a–7e, respectively under mercuric acetate/alcohol system or acetic anhydride/phosphoric acid system, then deacetylated in the solution of CH₃ONa/CH₃OH. All of the novel compounds were characterized by IR, ¹H NMR, ¹³C NMR, MS and elemental analysis. The structures of compounds 2e, 3e, 5a and 5c have been determined by X-ray diffraction analysis. Some of the synthesized compounds displayed PTP1B inhibition and microorganism inhibition.     

A convenient synthesis of novel pyranosyl homo-C-nucleosides and their antidiabetic activities

A series of pyranosyl homo-C-nucleosides have been synthesized by reaction of butenonyl C-glycosides (5a–5j, and 8) and cyanoacetamide in presence of t-BuOK followed by further modifications. The reaction proceeds by Michael addition of cyanoacetamide to the butenonyl C-glycosides and subsequent dehydrative cyclization and oxidative aromatization to give glycosylmethyl pyridones (6a–6j, 7a–7j, 9, and 10). The glycosylmethyl pyridones (6a–6e) on reaction with POCl₃ under reflux gave respective glycosylmethyl pyridines (11a–11e and 12a–12e) in good yields. The synthesized compounds were screened for their in vitro α-glucosidase, glucose-6-phosphatase and glycogen phosphorylase inhibitory activities. One of the pyridylmethyl homo-C-nucleoside, compound 11d, displayed 52% inhibition of glucose-6-phosphatase as compared to the standard drug sodium orthovanadate while compound 12a showed a significant antihyperglycemic effect of 17.1% in the diabetic rats as compared to the standard drug metformin.     

Cariniferosides A–F and other steroidal biglycosides from the starfish Asteropsis carinifera

Six new steroidal biglycosides, cariniferosides A–F (1–6), were isolated along with six previously known glycosides, 7–12, from the alcoholic extract of the starfish Asteropsis carinifera. The structures of 1–6 were determined by extensive NMR and ESIMS techniques. The isolated compounds did not show any apparent cytotoxicity in cancer cell lines HCT-116, RPMI-7951, and T-47D, but sulfated compounds 6, 11, and 12 demonstrated a significant inhibition of RPMI-7951 and T-47D cell colony formation in a soft agar clonogenic assay.     

A new epoxidic ganoderic acid and other phytoconstituents from Ganoderma lucidum

A new epoxidic ganoderic acid, 8α,9α-epoxy-3,7,11,15,23-pentaoxo-5α-lanosta-26-oic acid (1), together with the known compounds 3β-hydroxy-7,11,15,23-tetraoxo-5α-lanosta-8-en-26-oic acid (2), ergosta-7,22-diene-3β-yl pentadecanoate (3), ergosta-7,22-diene-3β-ol (4), β-sitosterol (5), fatty acids (6–10), fatty acid ester (11) and octadecane (12) were isolated from the fruiting bodies of Ganoderma lucidum from south India. Their structures were determined by ¹H, ¹³C, ¹³C DEPT, ¹H–¹H COSY, HMBC, HSQC, NOESY NMR, FT-IR, UV–vis and FABMS spectral analysis. Compounds (1–3) exhibited good antifungal activity against Candida albicans in disc diffusion assay (100 μg/disc). Steroid ester (3) showed moderate anti-inflammatory activity (59.7% inhibition, 100 mg/kg body weight) in carrageenan-induced paw edema.     

Synthesis,antitumour activities and molecular docking of thiocarboxylic acid ester-based NSAID scaffolds: COX-2 inhibition and mechanistic studies

A new series of NSAID thioesters were synthesized and evaluated for their in vitro antitumor effects against a panel of four human tumor cell lines, namely: HepG2, MCF-7, HCT-116 and Caco-2, using the MTT assay. Compared to the reference drugs 5-FU, afatinib and celecoxib, compounds 2b, 3b, 6a, 7a, 7b and 8a showed potent broad-spectrum antitumor activity against the selected tumour cell lines. Accordingly, these compounds were selected for mechanistic studies about COX inhibition and kinase assays. In vitro COX-1/COX-2 enzyme inhibition assay results indicated that compounds 2b, 3b, 6a, 7a, 7b, 8a and 8?b selectively inhibited the COX-2 enzyme (IC₅₀?=?～0.20–0.69?μM), with SI values of (>72.5–250) compared with celecoxib (IC₅₀?=?0.16?μM, COX-2 SI:?>?312.5); however, all the tested compounds did not inhibit the COX-1 enzyme (IC₅₀?>?50?μM). On the other hand, EGFR, HER2, HER4 and cSrc kinase inhibition assays were evaluated at a 10?μM concentration. The selected candidates displayed limited activities against the various tested kinases; the compounds 2a, 3b, 6a, 7a, 7b and 8a showed no activity to weak activity (% inhibition?=?～0–10%). The molecular docking study revealed the importance of the thioester moiety for the interaction of the drugs with the amino acids in the active sites of COX-2. The aforementioned results indicated that thioester based on NSAID scaffolds derivatives may serve as new antitumor compounds.     

Structural and functional analysis of aa3-type and cbb3-type cytochrome c oxidases of Paracoccus denitrificans reveals significant differences in proton-pump design

In Paracoccusdenitrificans the aa₃-type cytochrome c oxidase and the bb₃-type quinol oxidase have previously been characterized in detail, both biochemically and genetically. Here we report on the isolation of a genomic locus that harbours the gene cluster ccoNOQP, and demonstrate that it encodes an alternative cbb₃-type cytochrome c oxidase. This oxidase has previously been shown to be specifically induced at low oxygen tensions, suggesting that its expression is controlled by an oxygen-sensing mechanism. This view is corroborated by the observation that the ccoNOQP gene cluster is preceded by a gene that encodes an FNR homologue and that its promoter region contains an FNR-binding motif. Biochemical and physiological analyses of a set of oxidase mutants revealed that, at least under the conditions tested, cytochromes aa₃, bb₃. and cbb₃ make up the complete set of terminal oxidases in P. denitrificans. Proton-translocation measurements of these oxidase mutants indicate that all three oxidase types have the capacity to pump protons. Previously, however, we have reported decreased H⁺/e coupling efficiencies of the cbb₃-type     

Synthesis and biological evaluation of novel 4-(hetero) aryl-2-piperazino quinazolines as anti-leishmanial and anti-proliferative agents

A series of new class of 4-(hetero)aryl-2-piperazino quinazolines were synthesized and assessed for in vitro activity against extracellular promastigotes and intracellular amastigotes of Leishmania donovani. Among the compounds evaluated, compound 4bb and 4cb showed the selectivity index (SI) value > 8.03 and 4.21, respectively, which is promising as compared with sodium stilbogluconate (SSG) and pentamidine with the SI of 6.38 and 2.07, respectively. The synthesized compounds were also tested for anti-proliferation activity in a panel of mammalian cell lines. Compound 4aa which is quite inactive and 4ab which is hardly selective in anti-leishmanial assay are found to have significant activity in anti-proliferative assay.     

Synthesis,antitumour and antioxidant activities of novel α,β-unsaturated ketones and related heterocyclic analogues: EGFR inhibition and molecular modelling study

New α,β-unsaturated ketones 4a,b; 5a–c; and 6a,b; as well as 4-H pyran 7; pyrazoline 8a,b; isoxazoline 9; pyridine 10–11; and quinoline-4-carboxylic acid 12a,b derivatives were synthesized and evaluated for in vitro antitumour activity against HepG2, MCF-7, HeLa, and PC-3 cancer cell lines. Antioxidant activity was investigated by the ability of these compounds to scavenge the 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) radical cation (ABTS^?+). Compounds 6a, 6b, 7, and 8b exhibited potent antitumour activities against all tested cell lines with [IC₅₀] ?5.5–18.1 µΜ), in addition to significantly high ABTS^?+ scavenging activities. In vitro EGFR kinase assay for 6a, 6b, 7, and 8b as the most potent antitumour compounds showed that; compounds 6b, and 7 exhibited worthy EGFR inhibition activity with IC₅₀ values of 0.56 and 1.6?µM, respectively, while compounds 6a and 8b showed good inhibition activity with IC₅₀ values of 4.66 and 2.16?µM, respectively, compared with sorafenib reference drug (IC₅₀?=?1.28?µM). Molecular modelling studies for compounds 6b, 7, and 8b were conducted to exhibit the binding mode towards EGFR kinase, which showed similar interaction with erlotinib.     

Synthesis and evaluation of N-substituted indole-3-carboxamide derivatives as inhibitors of lipid peroxidation and superoxide anion formation

The in vitro antioxidant effects of novel N-substituted indole-3-carboxamides (I3CDs) 1-10 on rat liver microsomal NADPH-dependent lipid peroxidation (LP) levels and their free radicals scavenging properties were determined by the inhibition of superoxide anion formation (SOD). Among the synthesized compounds, 4, 5, 8 and 9 significantly inhibited SOD with an inhibition range at 84–100% at 10^{? 3} M concentration. The presence of halo substituents both ortho- and para- positions of these compounds resulted 100% inhibition of SOD. Comparison the activity results of halogenated and non-halogenated derivatives suggested that the halogenated compounds are more active than the non-halogenated compounds. On the other hand, the introduction of a para fluoro benzyl in the 1-position of indole (compounds 7, 8) has more impact on the SOD inhibition when the benzamide ring was mono halogenated. However, none of other compounds had a significant inhibitory effects on the level of lipid peroxidation.     

The cysteine 703 to isoleucine or histidine mutation of the oxidosqualene-lanosterol cyclase from Saccharomyces cerevisiae generates an iridal-type triterpenoid

The Cys703 to Ile or His mutation within Saccharomyces cerevisiae oxidosqualene-lanosterol cyclase ERG7 (ERG7^C703I/H) generates an unusual truncated bicyclic rearranged intermediate, (8R,9R,10R)-polypoda-5,13E,17E,21-tetraen-3β-ol, related to iridal-skeleton triterpenoid. Numerous oxidosqualene-cyclized truncated intermediates, including tricyclic, unrearranged tetracyclic with 17α/β exocyclic hydrocarbon side chain, rearranged tetracyclic, and chair–chair–chair tricyclic intermediates (compounds 3–9), were also isolated from the ERG7^C703X site-saturated mutations or the ERG7^F699T/C703I double mutation, indicating the functional role of the Cys703 residue in stabilizing the bicyclic C-8 cation and the rearranged intermediate or interacting with Phe699, and opened a new avenue of engineering ERG7 for producing biological active agents.     

猪链球菌4型疫苗用菌株的筛选

【背景】猪链球菌4型（Streptococcus suis serotype 4,SS4）分离率日益升高,对养殖业和公共卫生安全造成严重危害,目前尚无有效的SS4疫苗。【目的】筛选致病力强、抗原性好、遗传性状稳定的SS4疫苗菌种。【方法】以7株SS4分离株（代号为A1—A7）为受试菌株,通过累积法测定菌株半数致死量（LD₅₀）,ELISA测定免疫小鼠血清中IgG效价,攻毒保护试验测定免疫保护率,并采集小鼠脏器观察病理组织学变化。再连续传代培养受试菌株,分别对第10、20、30代菌株进行致病性和抗原性试验。【结果】A1—A7菌株对小鼠的LD₅₀分别为2.19×10⁸、1.76×10⁸、1.83×10⁸、1.01×10⁸、4.05×10⁸、1.19×10⁸和9.03×10⁷ CFU。二免7 d后,A1、A2、A3、A4、A6、A7免疫组IgG效价分别为1：1 600、1：1 600、1：3 200、1：6 400、1：3 200和1：6 400,免疫保护率分别为30%、30%、50%、70%、60%和80%,而且A4、A7免疫组小鼠组织病变较其余4组轻微。体外传至30代后,A4菌株的LD₅₀上升至3.81×10⁸ CFU,IgG效价下降至1：1 600,免疫保护率下降至40%,而A7菌株的LD₅₀上升至2.49×10⁸ CFU,IgG效价和免疫保护率稳定保持为1：6 400和80%,而且A7免疫组小鼠的组织病变较A4免疫组轻微。【结论】A7菌株（原始编号为HBgu18-4）具有强致病力和良好的抗原性,而且遗传性状均一、稳定,可作为SS4制苗候选菌株。     

The terminal oxidases of Paracoccus denitrificans

Three distinct types of terminal oxidases participate in the aerobic respiratory pathways of Paracoccus denitrificans. Two alternative genes encoding sub unit I of the aa₃-type cytochrome c oxidase have been isolated before, namely ctaDI and ctaDII. Each of these genes can be expressed separately to complement a double mutant (ActaDI, ActaDII), indicating that they are isoforms of subunit I of the aa₃-type oxidase. The genomic locus of a quinol oxidase has been isolated: cyoABC. Thisprotohaem-containing oxidase, called cytochrome bb₃, is the oniy quinoi oxidase expressed under the conditions used, in a triple oxidase mutant (ActaDI, ActaDII, cyoB::Km^R) an alternative cyto-chrome c oxidase has been characterized; this cbb₃-type oxidase has been partially purified. Both cytochrome aa₃ and cytochrome bb₃ are redox-driven proton pumps. The proton-pumping capacity of cytochrome cbb₃ has been analysed; arguments for and against the active transport of protons by this novel oxidase complex are discussed.     

New polyacetylene glucosides from the florets of Carthamus tinctorius and their weak anti-inflammatory activities

Eight new linear polyacetylene glucosides (1–8), containing two C₁₀-, one C₁₃- and five C₁₄-acetylenes, together with three known polyacetylenes (9–11) were isolated from the florets of Carthamus tinctorius L. Their structures were elucidated by means of spectroscopic methods and chemical evidence. The absolute configurations of compounds 3–9 were confirmed by Snatzke and Gerards’s method, observing the induced circular dichroism after addition of dirhodium tetrakis (trifluoroacetate) [Rh₂(OCOCF₃)₄] in CHCl₃. All the isolated compounds (1–11) were also tested for inhibitory activities against LPS-induced NO production in murine macrophages and just showed weak activities at concentrations of 1 × 10⁻⁵ M.     

The pre-steady state reaction of ferrocytochrome c with the cytochrome c-cytochrome aa3 complex

1. Using stopped-flow technique we have investigated the electron transfer form cytochrome c to cytochrome aa₃ and to the (porphyrin) cytochrome c-cytochromeaa₃ complex.2. In a low ionic strength medium, the pre-steady state reaction occurs in a biphasic way with rate constants of at least 2 · 10⁸ M^?1 · s^?1 and about 10⁷ M^?1 · s^?1 (I = 8.8 mM, pH 7.0, 10° C), respectively.3. A comparison of the rate constants, determined in the presence of an excess of cytochrome c with those found in the presence of an excess of cytochrome aa₃ reveals the existence of two slower reacting sites on the functional unit (2 hemes and 2 coppers) of cytochrome aa₃. On basis of these results we discuss various models. If no site-site interactions are assumed (non-cooperative model) cytochrome aa₃ has 2 high and 2 low affinity sites available for the reaction with ferrocytochrome c. If negative cooperativity occurs, cytochrome aa₃ has 2 high affinity sites which change into 2 low affinity sites upon binding of one cytochrome c molecule. The latter model is favoured.     

Synthesis and antioxidant,cytotoxicity and antimicrobial activities of novel curcumin mimics

Claisen-Schmidt condensation of 3-(1,2,3,6-tetrahydro-1-methylpyridin-4-yl)-2,4,5- trimethoxybenzaldehyde 3 and various aromatic, heterocyclic and alicyclic amides of 3- aminoacetophenone 6(a–s) afforded novel curcumin mimics. All the synthesized compounds were characterized by IR, ¹H NMR, Mass spectroscopy and evaluated for antioxidant, cytotoxicity and antimicrobial activity. Out of the 20 compounds screened, compounds 7i, 7l, 7q, and 7n have shown excellent radical scavenging activity, compounds 7o, 7t, 7f, and 7r have shown significant xanthine oxidase inhibition, and compounds 7a, 7k and 7l were found to be potent inhibitors of selected cancer cell lines. Compounds 7h, 7t, 7l, 7i, and 7e have shown good antibacterial activity, whereas compounds 7j, 7f, 7o, 7h, and 7t exhibited significant antifungal activity.     

Polarized Raman spectrum of single crystal uridylyl (3′–5′) adenosine: Local Raman tensors of some functional groups

Polarized Raman scattering measurements have been made of a single crystal of uridylyl(3′–5′)adenosine (UpA) by the use of a Raman microscope with 488.0 nm excitation. The UpA crystal belongs to space group P2₁ (monoclinic), and Raman intensities I_aa, I_bb, and I_c′c′, have been determined for each Raman band. These intensities correspond to the aa, bb, and c′c′ components of the crystal Raman tensor, where c′ is defined as an axis perpendicular to the crystallographic a axis in the ac plane. From these experimental data, and by taking the known crystal structure into account, anisotropic and isotropic molecular Raman tensors have been calculated for the following 11 normal modes: ring stretching modes of the adenine residue (protonated) at 1560, 1516, 1330, and 715 cm⁻¹; ring stretching modes of the uracil residue at 1696, 1657, 1615, 1228, and 790 cm⁻¹; PO⁻₂ symmetric stretching mode at 1080 cm⁻¹; P(—)O single bond stretching mode at 801 cm₋₁. These pieces of information of the Raman tensors are considered to be useful for estimating the orientations of the DNA and RNA strands in a biological complex from a polarized Raman spectroscopic measurement of such a complex. © 1998 John Wiley & Sons, Inc. Biopoly 45: 135–147, 1998     

Efficient synthesis of exomethylene- and keto-exomethylene-d-glucopyranosyl nucleoside analogs as potential cytotoxic agents

A novel series of exomethylene- and keto-exomethylene-d-glucopyranonucleosides with thymine, uracil, and 5-fluorouracil as heterocyclic bases have been designed and synthesized. Wittig condensation of the 3-keto glucoside 1 gave the corresponding 1,2:5,6-di-O-isopropylidene-3-deoxy-3-methylene-d-glucofuranose (2), which after hydrolysis and acetylation led to the precursor 1,2,4,6-tetra-O-acetyl-3-deoxy-3-methylene-d-glucopyranose (4).Compound 4 was condensed with silylated thymine, uracil, and 5-fluorouracil, respectively, deacetylated and acetalated to afford 1-(3′-deoxy-4′,6′-O-isopropylidene-3′-methylene-β-d-glucopyranosyl)pyrimidines 7a–c. Oxidation of the free hydroxyl group in the 2′-position of the sugar moiety led to the formation of the labile 1-(3′-deoxy-4′,6′-O-isopropylidene-3′-methylene-β-d-glucopyranosyl-2′-ulose)pyrimidines 8a–c. Finally, deisopropylidenation of the resulted derivatives 8a–c afforded the diol nucleosides 9a–c. The target keto-exomethylene analogs 9a–c were more cytostatic against a variety of tumor cell lines than the corresponding saturated-hydroxy-exomethylene derivatives 6. In particular, the 5-fluorouracil derivative 9c was highly cytostatic at an IC₅₀ (50% inhibitory concentration) ranging between 0.56 and 9.4 μg/mL, which was comparable to the free parental 5-fluorouracil base.     

Synthesis and bioactivities of novel thioether/sulfone derivatives containing 1,2,3-thiadiazole and 1,3,4-oxadiazole/thiadiazole moiety

A series of new thioether/sulfone compounds containing 1,2,3-thiadiazole and 1,3,4-oxadiazole/1,3,4-thiadiazole moiety were synthesized, the structures of all products were confirmed by IR, ¹H NMR, ¹³C NMR, and element analysis. Preliminary antifungal activity test showed that compound 8a exhibited moderate antifungal activity against Fusarium oxysporum at 50 μg/mL. Preliminary antiviral activity results showed that compounds 7a, 7c, 7d, 8a, and 9a displayed high antiviral activity against tobacco mosaic virus. The present work demonstrates that thioether/sulfone heterocyclic derivatives could be considered as new lead compounds for antiviral studies.     

Potential allelopatic effects of stilbenoids and flavonoids from leaves of Carex distachya Desf.

The potential allelopathic effects of 14 stilbenoids and five flavonoids, isolated from leaves of Carex distachya Desf., were evaluated on the seed germination and seedling growth of three coexisting Mediterranean species (Dactylis hispanica, Petrorhagia velutina, and Phleum subulatum). The structures of the metabolites have been elucidated on the basis of their spectroscopic features (1D and 2D NMR experiments and EI–MS and ESI–MS data). The bioassays showed species-specific effects of the metabolites from C. distachya, specially on the plant growth (root and shoot elongation) which resulted significantly stimulated or inhibited at 10⁻⁴ M concentration. The effects on root elongation is generally greater than the shoot growth at all the tested concentrations (10⁻⁴–10⁻⁸ M). Cluster of biological data showed interesting relationships between the chemical structures of the compounds and their biological effects.