PTP1B inhibitory activity of kaurane diterpenes isolated from Siegesbeckia glabrescens

Protein tyrosine phosphatase 1B (PTP1B) is considered as a therapeutic target for the treatment of diabetes and obesity. In our preliminary screening study, a MeOH extract of the aerial part of Siegesbeckia glabrescens was found to inhibit PTP1B activity at 30 μg/mL. Bioassay‐guided fractionation led to the isolation of two active diterpenes, ent-16βH,17-isobutyryloxy-kauran-19-oic acid (1) and ent-16βH,17-acetoxy-18-isobutyryloxy-kauran-19-oic acid (2), along with ent-16βH,17-hydroxy-kauran-19-oic acid (3). Compounds 1 and 2 inhibited the PTP1B activity with IC₅₀ values of 8.7 ± 0.9 and 30.6 ± 2.1 μM, respectively. Kinetic studies suggest that both 1 and 2 are non-competitive inhibitors of PTP1B. However, compound 3 substituted with a hydroxyl group at C-17 in kaurane-type showed no inhibitory effects towards PTP1B.     

New Aromatic Esters of Progesterone as Antiandrogens

The in vivo and in vitro antiandrogenic activity of four new progesterone derivatives: 4-bromo-17α-(p-fluorobenzoyloxy)-4-pregnene-3,20-dione 1,4-bromo-17α-(p-chlorobenzoyloxy)-4-pregnene-3,20-dione 2, 4-bromo-17α-(p-bromobenzoyloxy)-4-pregnene-3,20-dione 3 and 4-bromo-17α-(p-toluoyloxy)-4-pregnene-3, 20-dione 4 was determined. These compounds were evaluated as antiandrogens on gonadectomized hamster prostate and reduced the weight of the prostate glands in gonadectomized hamsters treated with testosterone 5 (T) or dihydrotestosterone 6 (DHT) in a similar manner to that of commercially available finasteride, thus indicating a potent in vivo effect. The in vitro studies showed that steroids 1–4 have a weak inhibitory activity on 5α-reductase with IC50 values of: 280 (1), 2.6 (2), 1.6 (3) and 114?μM (4). The presence of Cl and Br atoms in the C-17 benzoyloxy group tends to increase the inhibitory potency of the compounds.

The binding efficiency of the synthesized steroids 1–4 to the androgen receptor of the prostate gland is also evaluated. All compounds form a complex with the receptor and this explains the weight reduction of the seminal vesicles in the animals treated with DHT plus steroids 1–4.     

Regio- and enantio-selective acetylation of 3,3,3-trifluoro-2-arylpropane-1,2-diols using Candida antarctica lipase

Of nine commercially available lipases, lipase SP 435 from Candida antarctica, showed moderate enantioselectivity (E=17) for acetylation of racemic 3,3,3-trifluoro-2-phenylpropane-1,2-diol, 2, with vinyl acetate in diisopropyl ether (S selectivity). The other eight had low selectivities, with E values below 10. The selectivity and reactivity of SP 435 for 2 was markedly improved in dichloroethane (E=41). Moreover, SP 435 had moderate to high selectivity for the related compounds 3,3,3-trifluoro-2-(1-naphthyl)-propane-1,2-diol, 4, (E=20), 3,3,3-trifluoro-2-(indol-3-yl)propane-1,2-diol, 6, (E=80), and 3,3,3-trifluoro-2-(pyrrol-2-yl)-propane-1,2-diol, 8, (E=17).     

Labdane diterpenoids from Aframomum sceptrum: NMR study and antiparasitic activities

Two novel labdane diterpenoids, 15ξ-methoxy-labdan-8(17),11(E),13(14)-trien-15,16-olide (1) and 12(S)-hydroxy-15ξ-methoxy-labdan-8(17),13(14)-dien-15,16-olide (2) were isolated from the rhizomes of Aframomum sceptrum K. Schum (Zingiberaceae). Their structures were established on the basis of their spectroscopic data. Stigmast-4-en-6β-ol-3-one and caryophylene oxide were also obtained. In vitro trypanocidal and leishmanicidal activities of labdanes 1 and 2 were evaluated. Compound 2 exhibited activity similar to that of reference drugs against Leishmania donovani.     

Biotransformation of mestanolone and 17-methyl-1-testosterone by Rhizopus stolonifer

Abstract

Microbial transformation of mestanolone (1) using the plant pathogenic fungus, Rhizopus stolonifer, resulted in the production of two known metabolites, identified as 11α-hydroxymestanolone (3) and 6α-hydroxymestanolone (4). Transformation of 17-methyl-1-testosterone (2) by R. stolonifer yielded two known metabolites, methandrostenolone (5) and 11α,17β- dihydroxy-androsta-1,4-diene-3-one (6). These transformations included α-hydroxylations at C-11 and C-6, dehydrogenation at C-4, androsta and a demethylation at C-17 positions. Structures of transformed products were determined using spectroscopic techniques.     

Microbial hydroxylation of 17β-estradiol by Penicillium brevicompactum

Microbial hydroxylation of 17β-estradiol (1) with Penicillium brevicompactum, a fungal species not used in biotransformation so far, yielded four metabolites: 1, 3, 5-estratriene-3, 15α-diol-17-one (2); 1, 3, 5-estratriene-3, 6α, 17β-triol (3); 1, 3, 5-estratriene-3, 15α, 17β-triol (4); and 1, 3, 5-estratriene-3, 6α, 15α-triol-17-one (5). All the products were determined by ¹H NMR, ¹³C NMR, two-dimensional NMR, and HRMS techniques. Compounds 3, 4, and 5 are reported for the first time via microbial transformation, and 5 is a new compound as far as we know. Possible metabolic pathway of 17β-estradiol via Penicillium brevicompactum was also proposed.     

Synthesis,in vitro and in vivo antitumor and antiviral activity of novel 1-substituted benzimidazole derivatives

Abstract

A novel series of 5-nitro-1H-benzimidazole derivatives substituted at position 1 by heterocyclic rings was synthesized. Cytotoxicity and antiviral activity of the new compounds were tested. Compound 3 was more active than doxorubicin against A-549, HCT-116 and MCF-7. However, compound 3 showed no activity against human liver carcinoma Hep G-2 cell line. Compounds 9 and 17b (E) showed potency near to doxorubicin against the four cell lines. The acute toxicity of compound 9 on liver cancer induced in rats was determined in vivo. Interestingly, it showed restoration activity of liver function and pathology towards normal as compared to the cancer-bearing rats induced by DENA. Compounds 17a (Z), 17b (E) and 18a (Z) were the most promising compounds for their antiviral activity against rotavirus Wa strain.     

luxS基因缺失对禽致病性大肠杆菌O1、O2和O78三种血清型分离株的生物学特性影响

【目的】LuxS/AI-2型密度群体感应系统产生的自诱导信号分子AI-2(AI-2的产生需要luxS基因编码的Lux S蛋白参与)参与对细菌众多生理功能的调控。探讨luxS对不同血清型禽致病性大肠杆菌(Avian Pathogenicity Escherichia coli,APEC)生物学特性的影响。【方法】本研究以APEC优势血清型APECO_1(O_1血清型)、DE17(O_2血清型)、E940(O_(78)血清型)及其相应luxS缺失株为研究对象,对野生株和缺失株的生长特性、生物被膜形成、rdar(red,dry and rough)形态、运动性和耐药性等特性进行分析。【结果】luxS基因的缺失不影响APEC生长特性,但导致APEC不能产生AI-2;此外,luxS基因的缺失显著降低APECO_1和E940的生物被膜形成(P0.05),而DE17的生物被膜形成无显著变化。对各菌株的rdar形态和运动性检测结果表明,luxS基因的缺失改变了APECO_1的rdar形态,对DE17和E940并无影响;显著降低了APECO_1和DE17运动能力,对E940并无影响。荧光定量PCR检测结果表明,luxS基因的缺失显著降低APECO_1、DE17和E940与细菌运动性相关的鞭毛基因fli G和fli I的转录水平(P0.05)。此外,对各菌株的耐药性检测结果表明,luxS基因缺失导致APECO_1对头孢吡肟和丁胺卡那由耐药变为高敏,同时对氯霉素与E940相同由高敏变为耐药,但对DE17的耐药性无显著改变。【结论】luxS对APEC的生物学特性具有重要的调控作用,且这种调控具有菌株特异性。     

Novel steroidal saponins from Liriope graminifolia (Linn.) Baker with anti-tumor activities

Phytochemical investigation of the underground parts of Liriope graminifolia (Linn.) Baker resulted in the isolation of two new steroidal saponins lirigramosides A (1) and B (2) along with four known compounds. The structures were determined by extensive spectral analysis, including two-dimensional (2D) NMR spectroscopy and chemical methods, to be 3-O-{β-d-xylopyranosyl-(1→3)-α-l-arabinopyranosyl-(1→2)-[α-l-rhamnopyranosyl-(1→4)]-β-d-glucopyranosyl-(25S)-spirost-5-ene-3β,17α-diol (1), 1-O-[α-l-rhamnopyranosyl-(1→2)-β-d-xylopyranosyl]-(25R)-ruscogenin (2), 1-O-β-d-xylopyranosyl-3-O-α-l-rhamnopyranosyl-(25S)-ruscogenin (3), 3-O-α-l-rhamnopyranosyl-1-O-sulfo-(25S)-ruscogenin (4), methylophiopogonanone B (5), and 5,7-dihydroxy-3-(4-methoxybenzyl)-6-methyl-chroman-4-one, (ophiopogonanone B, 6), respectively. Compound 1 has a new (25S)-spirost-5-ene-3β,17α-diol ((25S)-pennogenin) aglycone moiety. The isolated compounds were evaluated for their cytotoxic activities against Hela and SMMC-7721 cells.     

Novel Carbocyclic Nucleosides Containing A Cyclobutyl Ring. Guanosine and Adenosine Analogues

Abstract

(1R,cis)-2-(3-Amino-2,2-dimethylcyclobutyl)ethanol (4) was used as a precursor in the synthesis of cyclobutyl nucleoside analogues containing guanine, 8-azaguanine, adenine or 8-azaadenine. All the compounds were evaluated as antiviral agents in a variety of assay systems. Some activity was noted for compound 13, 17, 19 and 20 against vaccinia virus and for compounds 11, 12, 13, 17, 19 and 20 against herpes simplex virus, at concentrations that were up to 10-fold below the cytotoxic concentrations for the host cells.     

Novel anti-inflammatory and analgesic agents: synthesis,molecular docking and in vivo studies

Twelve new derivatives of benzothiazole bearing benzenesulphonamide and carboxamide were synthesised and investigated for their in vivo anti-inflammatory, analgesic and ulcerogenic activities. Molecular docking showed an excellent binding interaction of the synthesised compounds with the receptors, with 17c showing the highest binding energy (–12.50?kcal/mol). Compounds 17c and 17i inhibited carrageenan-induced rat paw oedema at 72, 76, and 80% and 64, 73, and 78% at 1?h, 2?h, and 3?h, respectively. In the analgesic activity experiment, compounds 17c, 17?g, and 17i had ED₅₀ (µM/kg) of 96, 127, and 84 after 0.5?h; 102, 134, and 72 after 1?h and 89, 156, and 69 µM/kg after 2?h, respectively, which were comparable with 156, 72, and 70 µM/kg for celecoxib. The ulcerogenic index of the most active derivatives 17c and 17i were 0.82 and 0.89, respectively, comparable to 0.92 for celecoxib. The physicochemical studies of the new derivatives showed that they will not have oral bioavailability problems.     

Biotransformation of dehydroepiandrosterone with Macrophomina phaseolina and β-glucuronidase inhibitory activity of transformed products

The biotransformation of dehydroepiandrosterone (1) with Macrophomina phaseolina was investigated. A total of eight metabolites were obtained which were characterized as androstane-3,17-dione (2), androst-4-ene-3,17-dione (3), androst-4-ene-17β-ol-3-one (4), androst-4,6-diene-17β-ol-3-one (5), androst-5-ene-3β,17β-diol (6), androst-4-ene-3β-ol-6,17-dione (7), androst-4-ene-3β,7β,17β?triol (8), and androst-5-ene-3β,7α,17β-triol (9). All the transformed products were screened for enzyme inhibition, among which four were found to inhibit the β-glucuronidase enzyme, while none inhibited the α-chymotrypsin enzyme.     

EFFICIENT METHODS FOR THE SYNTHESIS OF [2-15N]GUANOSINE AND 2′-DEOXY[2-15N]GUANOSINE DERIVATIVES

The nucleophilic addition–elimination reaction of 2′,3′,5′-tri-O-acetyl-2-fluoro-O ⁶-[2-(4-nitrophenyl)ethyl]inosine (8) with [¹⁵N]benzylamine in the presence of triethylamine afforded the N ²-benzyl[2-¹⁵N]guanosine derivative (13) in a high yield, which was further converted into the N ²-benzoyl[2-¹⁵N] guanosine derivative by treatment with ruthenium trichloride and tetrabutyl-ammonium periodate. A similar sequence of reactions of 2′,3′,5′-tri-O-acetyl-2-fluoro-O ⁶-[2-(methylthio)ethyl]inosine (9) and the 6-chloro-2-fluoro-9-(β-D-ribofuranosyl)-9H-purine derivative (11), which were respectively prepared from guanosine, with potassium [¹⁵N]phthalimide afforded the N ²-phthaloyl [2-¹⁵N]guanosine derivative (15; 62%) and 9-(2,3,5-tri-O-acetyl-β-D-ribofuranosyl)-6-chloro-2-[¹⁵N]phthalimido-9H-purine (17; 64%), respectively. Compounds 15 and 17 were then efficiently converted into 2′,3′,5′-tri-O-acetyl[2-¹⁵N]guanosine. The corresponding 2′-deoxy derivatives (16 and 18) were also synthesized through similar procedures.     

Minor diterpenoid glycosides from the leaves of Stevia rebaudiana

From the commercial extract of the leaves of Stevia rebaudiana, three new diterpenoid glycosides were isolated besides eight known steviol glycosides including stevioside, rebaudiosides A–F and dulcoside A. The structures of the three compounds were identified as 13-[(2-O-β-d-glucopyranosyl-β-d-glucopyranosyl) oxy]-kaur-16-en-18-oic acid-(6-O-β-d-xylopyranosyl-β-d-glucopyranosyl) ester (1), 13-[(2-O-β-d-glucopyranosyl-β-d-glucopyranosyl) oxy]-17-hydroxy-kaur-15-en-18-oic acid β-d-glucopyranosyl ester (2), and 13-[(2-O-β-d-glucopyranosyl-β-d-glucopyranosyl) oxy]-17-oxo-kaur-15-en-18-oic acid β-d-glucopyranosyl ester (3) on the basis of extensive NMR and MS spectral studies. Another known diterpenoid glycoside, 13-[(2-O-β-d-glucopyranosyl-β-d-glucopyranosyl) oxy]-kaur-15-en-18-oic acid β-d-glucopyranosyl ester (4) was also isolated and its complete NMR spectral assignments were made on the basis of COSY, HSQC and HMBC spectral data.     

双歧杆菌对中国对虾原肌球蛋白致敏小鼠的免疫调控作用

【目的】比较研究婴儿双歧杆菌(Bifidobacterium infantis 13.085)对中国对虾原肌球蛋白致敏BALB/c小鼠预防与治疗过敏反应的差异,探究其对致敏小鼠Treg/Th17细胞平衡及相关细胞因子的影响。【方法】采用硫酸铵盐析及等电点沉淀法纯化中国对虾原肌球蛋白(TM),将中国对虾TM和弗氏佐剂混合液腹腔注射诱发BALB/c小鼠致敏,建立动物过敏模型。将实验小鼠随机分为正常对照组、治疗对照组、双歧杆菌治疗组、预防对照组和双歧杆菌预防组。观察分析小鼠过敏症状(腹泻、肺组织HE染色比较、称重法测定小鼠体重和脾脏脏器系数变化),采用ELISA测定小鼠血清中特异性IgE、IgG2a和组胺的含量,采用流式细胞术测定脾脏T淋巴细胞亚群(Treg、Th17)数量,采用荧光定量PCR测定脾脏中Treg型和Th17型细胞因子和转录因子的表达量。【结果】纯化得到中国对虾原肌球蛋白纯度为84.93%,得率为60.88%。体内试验表明,双歧杆菌治疗组和预防组相比于对照组,腹泻和过敏症状均有明显的缓解;不同时期的双歧杆菌干预均对过敏小鼠肺组织症状有明显的改善作用,且可降低过敏小鼠的脾脏脏器系数。第56天实验周期结束后发现,相比预防对照组和治疗对照组,双歧杆菌预防组和治疗组小鼠血清中特异性IgE和组胺含量显著降低(P0.05),脾脏Treg/Th17比值显著升高(P0.05),Th17型细胞因子IL-17A mRNA表达水平显著降低(P0.01);双歧杆菌治疗组相对于治疗对照组,Treg型细胞因子CD25mRNA表达水平显著升高(P0.01)。此外,双歧杆菌治疗组血清特异性IgE及IL-17A mRNA转录水平显著低于双歧杆菌预防组(P0.05),而Treg/Th17比值及CD25 mRNA转录水平显著高于预防组(P0.05)。【结论】双歧杆菌13.085能有效缓解小鼠过敏症状,且治疗免疫调控效果优于预防效果,其作用可能通过平衡Treg/Th17细胞亚群数量,促进Treg型细胞因子表达而抑制Th17型细胞因子分泌,从而阻断炎性抗体及组胺释放。     

贺兰山东麓优良本土酿酒酵母筛选及发酵特性分析

【背景】商业酵母的使用造成葡萄酒同质化问题严重,发掘优良本土酿酒酵母具有十分重要的意义。【目的】从168株宁夏本土酿酒酵母菌株中筛选出性能优良、具有出色葡萄酒发酵能力的菌株。【方法】基于杜氏管发酵试验和乙醇、高糖等耐受性试验分析产H2S能力及生长曲线测定的方法,筛选出发酵力好、耐受性强、低产H2S的本土酿酒酵母进行赤霞珠葡萄酒发酵试验,测定葡萄酒样基础理化指标、酚类物质和挥发性成分,探究筛选出的酿酒酵母发酵特性。【结果】初步筛选出发酵快速,能适应13%乙醇、350 g/L葡萄糖、250 mg/L SO2、pH 1.0的生存环境且低产H2S的4株本土酿酒酵母YC-E8、QTX-D17、QTX-D7、YQY-E18。菌株YC-E8产甘油能力强,所发酵酒样香气与商业酵母XR、F33最为接近,适用于赤霞珠葡萄酒的发酵。菌株QTX-D17发酵酒样中酒精、单宁、总酚和花色苷含量最高,表现出本土酿酒酵母优良的发酵特性。菌株QTX-D7所发酵酒样香气中乙酸乙酯、辛酸乙酯、1-壬醇等物质含量较高,赋予了葡萄酒香蕉味、苹果味、菠萝味、椰子味等愉悦花果香。【结论】最终筛选出3株优良本土酿酒酵母QTX-D17...     

Synthesis of Methylene-Bridged Analogues of Nicotinamide Riboside,Nicotinamide Mononucleotide and Nicotinamide Adenine Dinucleotide

Abstract

5-O-tert-Butyldimethylsilyl-1,2-O-isopropylidene-3(R)-(nicotinamid-2-ylmethyl)-α-D-ribofuranose (11a) and ?3(R)-(nicotinamid-6-ylmethyl)-α-D-ribofuranose (11b) were prepared by condensation of 5-O-tert-butyldimethylsilyl-1,2-O-isopropylidene-α-D-erythro-3-pentulofuranose (10) with lithiated (LDA) 2-methylnicotinamide and 6-methylnicotinamide, respectively, and then deprotected to give 1,2-O-isopropylidene-3-(R)-(nicotinamid-2-ylmethyl)-α-D-ribofuranose(12a) and 1,2-O-isopropylidene-3(R)-(nicotinamid-6-ylmethyl)-α-D-ribofuranose (12b). Benzoylation as well as phosphorylation of compounds 12 afforded the corresponding 5-O-benzoate (13b) and 5-O-monophosphates (14a and 14b). Treatment of 13b with CF₃COOH/H₂O caused 1,2-de-O-isopropylidenation with simultaneous cyclization to the corresponding methylene-bridged cyclic nucleoside - 3′,6-methylene-1-(5-O-benzoyl-β-D-ribofuranose)-3-carboxamidopyridinium trifluoro-acetate (8b) - restricted to the “anti” conformation. In a similar manner compounds 14a and 14b were converted into conformationally restricted 2,3′-methylene-1-(β-D-ribofuranose)-3-carboxamidopyridinium-5′-monophosphate (9a - “syn”) and 3′,6-methylene-1-(β-D-ribofuranose)-3-carboxamido -pyridinium-5′monophosphate (9b - “anti”) respectively. Coupling of derivatives 12a and 12b with the adenosine 5′-methylenediphosphonate (16) afforded the corresponding dinucleotides 17. Upon acidic 1,2-de-O-isopropylidenation of 17b, the conformationally restricted P¹-[6,3′-methylene-1-(β-D-ribofuranos-5-yl)-3-carboxamidopyridinium]-P²-(adenosin-5′-yl)methylenediphosphonate 18b -“anti” was formed. Compound 18b was found to be unstable. Upon addition of water 18b was converted into the anomeric mixture of acyclic dinucleotides, i. e. P¹-[3(R)-nicotinamid-6-ylmethyl-D-ribofuranos-5-yl]-P²-(adenosin-5′-yl)-methylenediphosphonate (19b). In a similar manner, treatment of 17a with CF₃COOH/H₂O and HPLC purification afforded the corresponding dinucleotide 19a.

     

Discovery of novel inhibitors for human intestinal maltase: virtual screening in a WISDOM environment and in vitro evaluation

Human intestinal maltase (HMA) is an α-glucosidase that hydrolyses α-1,4-linkages from the non-reducing end of malto-oligosaccharides. HMA is an important target to discover of new drugs for the treatment of type 2 diabetes. In this study, 308,307 compounds were virtually screened with HMA using Autodock 3.0.5 in a WISDOM production environment to discover novel inhibitors. The 42 top-scoring free binding energy compounds, representing 17 groups containing potential hydrogen bonding with key residues in the active site pocket of HMA, were tested in vitro for their inhibitory activities against recombinant HMA expressed from Pichia pastoris. Compounds 17 and 18 were competitive inhibitors exclusively for HMA without any in vitro inhibition for human pancreatic α-amylase. The K _i values were 20 μM for both compound 17 and 18.     

Microbial hydroxylation of epiandrosterone by Aspergillus candidus

In this work, Aspergillus candidus MRC 22634 converted epiandosterone 1 into 10 hydroxylated metabolites. A. candidus has been shown to hydroxylate 1 predominantly at C-11α, C-1α, and C-15β with minor hydroxylations occurring at C-14α and C-7α. Oxidation at C-3, reduction at C-17, and C-3 epimerization of some of the remaining substrate have also been shown. 15β-Hydroxylation and C-3 epimerization of 1 by a fungus were reported for the first time. Two of the metabolites, 1α,3α-dihydroxy-5α-androstan-17-one 4 and 15β,17β-dihydroxy-5α-androstan-3-one 7, were identified as new compounds.