2-乙酰氨基-3,4,6-三乙酰葡萄糖的合成方法改进

以氨基葡萄糖盐酸盐为原料,在乙酸酐和浓硫酸的作用下合成1,3,4,6-四乙酰基氨基葡萄糖硫酸盐(2)。2在无水醋酸钠和氢氧化钡的作用下进行乙酰基转移反应,合成了2-乙酰氨基-3,4,6-三乙酰葡萄糖。最高收率达84．8％。讨论了乙酰基转移反应的最佳温度和最佳投料比。     

Identification of Free and Glycosidically Bound Volatiles and Glycosides by Capillary GC and Capillary GC‐MS in “Lulo del Chocó” (Solanum topiro)

The volatile constituents of lulo del Chocó (Solanum topiro) fruit pulp obtained by liquid‐liquid extraction were analyzed by capillary GC and capillary GC‐MS. In total, 30 components were identified with methyl salicylate, hexadecanoic acid, hexanal, guaiacol, ethyl butanoate, and ethyl acetate being the major components. Chirospecific MDGC analysis revealed the predominance of (R)‐ethyl‐3‐hydroxybutanoate (ee 40%) and the presence of racemic mixtures both of δ‐octalactone and of δ‐decalactone. For γ‐hexalactone, γ‐octalactone, and γ‐decalactone enantiomeric distributions of 22.4 : 77.6, 22.9 : 77.1, and 20.0 : 80.0, (R) : (S), respectively, were determined. Glycosidically bound aroma compounds were identified by capillary GC and capillary GC‐MS after isolation of the glycosidic fraction obtained by Amberlite XAD‐2 adsorption and methanol elution followed by hydrolysis with a commercial pectinase enzyme. In total 13 bound aroma compounds (aglycones) were identified. These aglycones mainly consisted of compounds exhibiting aromatic structures. Additionally, with the aid of capillary GC and capillary GC‐MS (EI and NCI) of trifluoroacetylated derivatives we identified eight glucosides: the novel 3,6‐epoxy‐7‐megastigmen‐5,9‐diol β‐D‐glucopyranoside and the hexyl, benzyl, linalyl oxide (furanic), 2‐phenylethyl, vomifolyl (isomer 1), (6S,9R)‐vomifolyl, and scopoletin β‐D‐glucopyranosides.     

Silviridoside: A New Triterpene Glycoside from Silene viridiflora with Promising Antioxidant and Enzyme Inhibitory Potential

A new triterpene glycoside, silviridoside, was isolated from the aerial parts of Silene viridiflora (Caryophyllaceae) using different chromatographic techniques. The structure of silviridoside was comprehensively elucidated as 3-O-β-D-galacturonopyranosyl-quillaic acid 28-O-β-D-glucopyranosyl-(1→2)-[α-L-rhamnopyranosyl-(1→3)]-β-D-fucopyranosyl ester by one- and two-dimensional nuclear magnetic resonance (NMR) spectroscopy and high-resolution mass spectrometry (HR-MS). Silviridoside showed promising antioxidant activity in different antioxidant assays such as 2,2-diphenyl-1-picrylhydrazyl (DPPH) (2.32 mg TE/g), 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) (1.24 mg TE/g), cupric-reducing antioxidant capacity (CUPRAC) (9.59 mg TE/g), ferric-reducing antioxidant power (FRAP) (5.13 mg TE/g), phosphomolybdenum (PHD) (0.28 mmol TE/g), and metal-chelating (MCA) (6.62 mg EDTA/g) assays. It exhibited a good inhibitory potential on acetylcholinesterase (AChE) (2.52 mg GALAE/g), butyrylcholinesterase (BChE) (7.16 mg GALAE/g), α-amylase (0.19 mmol ACAE/g), α-glucosidase (1.21 mmol ACAE/g), and tyrosinase (38.83 mg KAE/g). An in silico evaluation of the pharmacodynamic, pharmacokinetic, and toxicity properties of silviridoside showed that the new compound exhibited reasonable pharmacodynamic and pharmacokinetic properties without any mutagenic effect, but slight toxicity. Thus, it could be concluded that silviridoside could act as a promising lead drug for pharmaceutical and nutraceutical developments to combat oxidative stress and various disorders, but a future optimization is necessary.     

Laceioside,a new cycloartane saponin from Astragalus tephrosioides Boiss. var. lacei (Ali) Kirchoff.

Phytochemical investigation of the aerial parts of Astragalus tephrosioides Boiss. var. lacei (Ali) Kirchoff. (Family Fabaceae) resulted in the isolation of a new cycloartane glycoside laceioside (1). The structure of the previously undescribed compound 1 was established as 16β-acetyloxy-3-O-β-d-glucopyranosyloxy-cycloartan-11α,24ξ, 25-triol. The structure elucidation of compound 1 was based primarily on 1D and 2D-NMR techniques including ¹H and ¹³CNMR spectra, DEPT and by 2D COSY, HSQC and HMBC experiments.     

Membrane-bound Na+,K+-ATPase as the cardiac glycoside receptor

DSC studies are carried out to characterize Na⁺,K⁺-ATPase isolated from pig kidney in its natural membrane environment as well as in its purified state upon detergent treatment. The transition temperatures of the investigated thermal protein unfolding process, observed between 43 and 64.5° C, depend on the local membrane environment as well as onpH. In addition, the transition temperature is significantly increased upon binding of different cations and ligands which are known to interact with the enzyme. Evidence for a lipid phase transition around 23 °C in the original biological membrane is reported.The application of a calorimeter equipped with removable cells appears to be more suitable for the investigation of this type of membrane sample than an instrument with fixed capillary cells. Filling the sample capillary cell with an usual syringe, consisting of a long and thin needle, can influence the experimental results.Na⁺, K⁺ -ATPase acts as the receptor for cardiac glycoside binding. The thermodynamic parameters of this binding process are determined by titration calorimetry. The binding of ouabain, as a typical example, is unusually slow and is enthalpy driven. The enthalpy change upon binding enthalpy is –75 kJ mol^–1 at 25 °C. The surprisingly low stoichiometric coefficient, resulting from an evaluation based on a simple one step binding model, is interpreted in terms of a dimeric receptor unit.The authors are grateful to E. Lewitzki, H. Ruf, E. Schick and F. Thommen for stimulating discussions, to A. Schacht for skilfull enzyme preparations and to the German Research Foundation for financial support (SFB 169).     

Chemical Constituents from the Root Bark of Rodgersia Sambucifolia

A new demethylacetovanillochromene glycoside, 2,2‐dimethyl‐2H‐(8‐hydroxy‐6‐acetyl)‐[2,3‐b] pyran‐8‐O‐β‐D‐apiofuranosyl‐(1 →6)‐β‐D‐glucopyranoside ( 1 ), together with twenty‐three known compounds, have been isolated from the root bark of Rodgersia sambucifolia. These known compounds include two diterpenoids, three flavonoids, two catechins, four lignans, two benzenoids, two isocoumarins, two steroids and six monoterpene glycosides, which were determined by means of spectral analyses.     

一种新的保护的2-脱氧-2-氨基葡二糖合成

以氨基葡萄糖盐酸盐为原料制得糖基给体3,4,6-三-氧-乙酰-2-脱氧-2-(2,2,2-三氯乙氧)甲酰胺基-α-D-吡喃葡萄糖基三氯乙酰亚胺酯(5)和糖基受体烯丙基-4,6-氧-亚苄基-2-脱氧-2-(2,2,2-三氯乙氧)甲酰胺基-α-D-吡喃葡萄糖苷(7).在三甲基硅基三氟甲基磺酸酯(TMSOTf)条件下,给体5与受体7反应得到一种新的二糖烯丙基-3,4,6-三-氧-乙酰-2-脱氧-2-(2,2,2-三氯乙氧)甲酰胺基-β-D-吡喃葡萄糖-(1→3)-4,6-氧-亚苄基-2-脱氧-2-(2,2,2-三氯乙氧)甲酰胺基-α-D-吡喃葡萄糖糖苷(10),收率为39.2%.当7在无水BaO和Ba(OH)2·8H2O的条件下与BnBr进行3-OH苄基化反应时,却得到了烯丙基-3-氧-苄基-4,6-氧-亚苄基-2-脱氧-2-羟甲酰胺基-α-D-吡喃葡萄糖苷(8).改用Ag2O条件下与BnBr进行苄基化,得到预期的烯丙基-3-氧-苄基-4,6-氧-亚苄基-2-脱氧-2-(2,2,2-三氯乙氧)甲酰胺基-α-D-吡喃葡萄糖苷(9),从而避免了氨基保护基三氯乙氧甲酰基的水解.标题化合物10对枯草芽孢杆菌、葡伎根霉等微生物有一定的抑制作用.     

胶束电动毛细管色谱法用于中成药原料银杏浸膏中黄酮的质量控制

研究建立了胶束电动毛细管色谱法测定中药银杏浸膏(GBE)中黄酮的方法。以SDS作表面活性剂，在 25kV电压下，考察了不同缓冲体系的pH值及浓度对黄酮的3个水解产物槲皮素、山奈酚、异鼠李素分离度的影响。结果表明，选择25mmol/L硼砂-25mmol/L磷酸二氢钾—1％(V／V)甲醇电解液，15min之内槲皮素、山奈酚、异鼠李素可得到很好分离。把MECC定量分析的结果与反相高效液相色谱进行了对比，表明所建立的MECC法用于中药中的黄酮测定是可靠的。     

Four new constituents from Taraxacum mongolicum

Two new flavone glycosides,isoetin-7-O-β-D-glucopyranosyl-2′-O-α-L-arabinopyranoside (1) and isoetin-7-O-β-D-glucopyr- anosyl-2′-O-α-D-glucopyranoside (2),a new lignan,mongolicumin A (3),and a new guaianolide,mongolicumin B (4) were isolated from the aerial part of Taraxacum mongolicum.Their structures were elucidated mainly by spectral analyses.     

Synthesis of the Rhodiola rosea glycoside rosavin

A synthetic scheme was proposed for the glycoside rosavin that includes a one-step glycosylation of cinnamyl alcohol with a disaccharide. The structure of the product was confirmed by PMR and ¹³C NMR spectroscopy. __________ Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 323–324, July–August, 2006.