罗汉果皂苷Ⅳa碳氢NMR信号的归属

目的　研究传统中药罗汉果的皂苷类化学成分罗汉果皂苷IVa的结构 ,总结其结构的NMR特点。方法　采用常法提取、分离、纯化罗汉果皂苷IVa ,应用NMR方法 ( 1 HNMR、1 3CNMR、DEPT、1 H 1 HCOSY、HSQC、HMBC和NOESY)和计算机分子模拟研究其结构。结果　对罗汉果皂苷IVa的1 H和1 3C信号进行了归属 ,并为该类型化合物的结构确定提供了波谱学依据。结论　包括1 H 1 HCOSY、HSQC、HMBC、NOESY的一维和二维核磁共振波谱技术是对结构进行无创伤性分析的有力工具。NMR方法确定的结构与计算机分子模拟的最优构象一致。     

莫沙必利的核磁共振氢谱与碳谱指定

用一维和二维核磁共振技术(gCOSY，gNOESY，gHMQC，gHMBC)，对莫沙必利的核磁共振氢谱与碳谱进行了指定。计算机模拟的结果证明了我们对吗啉环优势构象的推测。     

米非司酮衍生物制备中格氏反应副产物的结构鉴定

目的确定米非司酮衍生物制备过程中格氏反应一步的副产物的结构,并分析反应机理.方法通过一维及二维光谱分析和元素分析确定副产物的结构. 结果证实了副产物是11,17位双加成的格氏反应的产物. 结论这是首次对此步副产物用光谱进行C,H的详细归属.     

云南美登木共生放线菌菌株CS产生的新多羟基环己烷衍生物

从云南美登木共生放线菌菌株(Streptomyces sp.)CS的发酵产物中分离得一个新的多羟基环己烷衍生物,并通过波谱学特征鉴定化合物的结构为1-isobutyroxymethyl cyclohex-1(6)-ene-2,3,4,5-tetrol-2-isobutyrate.     

Urinary stability of carboxycyclophosphamide and carboxyifosfamide, two major metabolites of the anticancer drugs cyclophosphamide and ifosfamide

Phosphorus-31 nuclear magnetic resonance spectroscopy was used to evaluate the stability of carboxycyclophosphamide (CXCP) and carboxyifosfamide (CXIF) in human urine at pH 7.0 and 5.5 at 25°, 8°, −20°, and −80 °C. At 25 °C and pH 7.0, CXCP and CXIF are relatively stable (≈10% degradation in 24 h). In contrast, they are much less stable at pH 5.5 (≈80% degradation of CXIF and ≈50% degradation of CXCP in 24 h). The rate of degradation of CXCP and CXIF was a function of the storage temperature of the urine samples but, even at −80 °C, was not negligible: ≈30% degradation for CXCP irrespective of pH and ≈40% and 50% degradation for CXIF at pH 7.0 and 5.5, respectively, after storage for 6 months. CXCP was more stable than CXIF at either pH (7.0 or 5.5) and at all storage temperatures (8°, −20°, or −80 °C) of the urine samples. CXCP and CXIF were more stable at pH 7.0 than at pH 5.5, although this difference fell with decreasing temperatures to be almost negligible at −80 °C. To ensure a true estimate of CXCP and CXIF levels, urine samples must be frozen and stored at −80 °C within a few hours of micturition. CXCP and CXIF assays should also be carried out within 2 months and 1 month of storage, respectively. Received: 13 July 1996 / Accepted: 20 January 1997     

Comparison of action of the anti-neoplastic drug lonidamine on drug-sensitive and drug-resistant human breast cancer cells:31 P and 13C nuclear magnetic resonance studies

Lonidamine (LND) is a relatively new anti-cancer drug,and several clinical trials have indicated that it may be effectivein combinations with other therapeutic modalities. LND isclassified within the metabolic inhibitor agents. Multidrugresistance (MDR) phenomenon is often associated with increasedenergy requirements, and enhanced glycolysis rate. These studieswere performed to delineate the mechanism of action of LNDon MDR human breast cancer cells, and to investigate whetherLND as a single agent, or in combination with anotheranti-metabolism drug, 2-deoxyglucose (2-DG), may be usefulagainst MDR tumors. The effects of LND on intact perfuseddrug-sensitive (WT) and 33-fold resistant to Adriamycin(Adr) MCF-7 cells, embedded in alginate micro capsules, were continuouslymonitored by ³¹P and ¹³C nuclearmagnetic resonance (NMR) spectroscopy. ³¹PNMR studies showed that LND induced intracellular acidificationand depletion of NTP in both WT and Adr cells. However, pH and NTPlevels decreased less in the Adr cells than in the WT cells(p < 0.05 for both parameters). ¹³CNMR demonstrated that LND inhibited lactate transport,and lactate signals were elevated in both cell lines. However, theintracellular lactate levels increased to a greater extentin the WT than in the Adr cells (p < 0.05).There were major differences in the effects of LND onmetabolism between sensitive and resistant cells.While LND enhanced glucose uptake in the WT cells, and itsadministration was followed by continuous increase oflactate signal, both processes were not affected by LNDin the Adr cells. 2-DG is a glucose analogue that inhibitsboth cellular uptake and utilization of glucose, leading to cell starvation. Combined treatment with LND and2-DG yielded at best additive, but not synergistic,cellular toxicity, and the metabolic effects of LNDwere attenuated by 2-DG. These results showed that the principalmechanism of action of LND is inhibition of lactate transportleading to intracellular lactate accumulation and acidificationin both WT and Adr cells. The Adr cells were only 2-fold resistantto LND (compared to the WT cells), and since cellular uptakeof alkaloid chemotherapy is improved in acidic environment,LND may have a role in the treatment protocols of MDR tumors,especially when given as the initial means for inductionof intracellular acidification.     

阿屈非尼的合成和NMR研究

目的:合成阿屈非尼的2种异构体.方法:以二苯基甲醇和巯基乙酸为原料经4步反应合成目标产物,并对其进行1H、13C-NMR、1H-1HCOSY(氢-氢相关二维谱)、HMQC(氢核检测的异核多量子碳氢相关谱)和HMBC(氢核检测的异核多量子远程碳氢相关谱)等2D-NMR实验.结果:合成了阿屈非尼,4步反应总收率为49.2%.结论:首次报道了阿屈非尼的2种异构体氢谱和碳谱数据.新的合成方法为为阿屈非尼及其代谢物的研究提供了物质基础和理论依据.     

NMR studies of the inclusion complex between β-cyclodextrin and paroxetine

A ¹H and ¹³C NMR study on the inclusion complex of paroxetine with β-cyclodextrin was carried out in order to define the stoichiometry of the association and its strength. Proton and carbon chemical shift measurements of paroxetine and β-cyclodextrin were performed at several molar ratios and temperatures, allowing the determination of a 1:1 stoichiometry and an association constant value of the order of 2 × 10³ for the paroxetine–β-cyclodextrin complex. Overhauser effects in the rotating frame were also measured, and the experimental interproton distance constraints have been used for molecular model building of the complex. The obtained model indicates that the benzodioxolyl moiety of paroxetine is deeply inserted in the cavity of the cylindrical structure of β-cyclodextrin, while the fluoro-phenyl ring lays above the wider rim.     

复方人参注射液核磁共振指纹图谱研究

目的:建立复方人参注射液(人参、陈皮等)的核磁共振指纹图谱,探索质量控制的新方法.方法:运用核磁共振技术对复方人参注射液的中间体和成品进行指纹图谱研究,探索简便易行的指纹图谱分析方法.结果:通过对中间体和注射液的图谱相似度分析,表明工艺流程稳定,重现性良好.结论:核磁共振技术可以作为中成药指纹图谱研究的辅助方法以控制中药质量.     

Novel GHB-derived natural products from European mistletoe (Viscum album)

Abstract

Context: The European white-berry mistletoe [Viscum album L. (Loranthaceae)] is among the oldest known medicinal plants. At present the most important application of mistletoe extracts is in the treatment of cancer. However, natural products specific to mistletoe have rarely been encountered in the current literature.

Objective: To discover novel natural products specific to European mistletoe.

Materials and methods: European mistletoe was extracted with methanol, purified to partition against diethyl ether and further purified with XAD-7 column chromatography. Pure compounds were separated by Sephadex column chromatography and preparative HPLC. The structures of the novel compounds were established using a combination of several 2D NMR spectroscopic techniques and mass spectrometry.

Results: A new type of natural product derived from the methyl ester of γ-hydroxybutyric acid (GHB) coupled to hydroxybenzoic acids, namely 3-(3′-carbomethoxypropyl) gallic acid and 3-(3′-carbomethoxypropyl)-7→3″-protocatechoyl galloate were characterized from European white-berry mistletoe. Condensation of the 3-hydroxyl of gallic acid with the 4-hydroxyl of GHB significantly reduced the radical scavenging properties of the former compound.

Discussion and conclusion: The characterized compounds define a novel group of natural products that may be of particular interest because it appears that the two new compounds are not closely related to any known natural product.