雪胆甲素甙的化学结构

从葫芦科雪胆属园果雪胆的块根中分离到一种新的苦味质——雪胆甲素甙,分子式C₃₈H₆₀O₁₃,熔点154.2～158.2℃,[α]_d⁷+44°,通过水解和光谱分析证实雪胆甲素甙为19-失碳-9β-甲基-10α-2β,3α,16α,20,25-五羟基-△⁵-羊毛甾烯-11,20-双酮-25,-乙酸酯·2-O-β-D-吡喃葡萄糖甙(Ⅱ)。     

16α-甲基-3β,17α-二羟基-5α-孕甾-20酮-3β-醋酸酯的微生物转化

16 α-Methyl-3 β,17 α-dihydroxy-5 α-pregnane-20-one-3 β-acetate (Ⅰ) was prepared from tigogenin and then incubated with a mixture of Mycobacterium smegmatis (MS₁) and Arthrobacter simplez (A₁) to give 16 α-methyl-17 α-hydroxy-△^{1, 4}-pregnadiene-3,20-dione (Ⅱ) with about 63% yield.Compound (Ⅱ) when incubated with Absidia glauca (AG₁) gave about 55% yield of 16 α-methyl-11 α, 17 α-dihydroxy-pregna-1,4-diene-3,20-dione (Ⅳ).     

拟人参皂苷F11在大鼠体内的药物代谢研究

目的探讨拟人参皂苷F11在大鼠体内的药物代谢产物及其过程.方法ip拟人参皂苷F₁₁后,应用TLC分析排泄物中的代谢产物,并利用制备薄层分离制备代谢产物,通过波谱解析(MS,¹HNMR,¹³CNMR,¹H-¹HCOSY)确定其结构.结果从粪便中分离鉴定了3种代谢产物,分别为拟人参皂苷R_T5,ocotillol和1个新的代谢产物F-3-1,并确定其结构为6-O-α-L-吡喃鼠李糖基(1-2)-β-D-吡喃葡糖基-(20S,23S,24R)-达玛-20(24)-环氧-3β,6α,12β,23,25-五醇(6-O-α-L-rhamnopyranosyl-(1-2)-β-D-glucopyranosyl-(20S,23S,24R)-dammar-20(24)-epoxy-3-β,6α,12β,23,25-pentanol).但在尿液和胆汁中并未发现任何代谢产物.结论拟人参皂苷F₁₁不被肝脏代谢,但胆汁排泄物可在肠道被代谢为水解和氧化产物.     

雌三醇11位取代物的合成

为了寻找新的雌激素类药物,合成了(11),(14a)～(14d)等五个雌三醇的11位取代物(11α-OH,11β-OH,11α-OCH₃,11β-OCH₃,11β-OAc)供药理筛选。化合物的制备采用了新的合成路线;对△⁹⁽¹¹⁾-雌酚酮缩酮物(3)及11位取代雌酚酮烯醇酯化合物(10a),(10b)的硼氢化反应进行了考察,分离得到了9α-羟基物(5)及11位取代的16表雌三醇(13a)、(13b)等副产物。所有化合物的结构均通过光谱解析和化学转换得以确证。     

降压药物的合成研究——Ⅲ.β-N-(带有α-取代甲基的哌啶基)乙胍和有关化合物的合成

从胍乙啶(Ⅰ)和潘必啶(Ⅱ)结构出发,作者设计了β-N-(2,2,6,6-四甲基哌啶)乙胍(Ⅲ_a,BD-31)及其β-N-(2-甲基或顺式2,6-二甲基哌啶)乙胍(Ⅲ_b,BD-37;Ⅲ_c,BD-38)类似物。它们由不同的α-甲基哌啶与氯乙腈生成相应的N-(α-甲基哌啶)乙腈(Ⅷ_a,b,c),经氢化锂铝还原变成β-N-(α-甲基哌啶)乙胺(Ⅶ_a,b,c),再用硫酸甲基异硫脲引入胍基制得。药理试验发现BD-31,32(Ⅵ),33(Ⅶ_a),38均有明显降压作用,其中以BD-31作用最强。     

6α-甲基-17α-羟基-黄体酮和6α-甲基-17α-羟基-11去氧-皮质酮-21-乙酸酯的微生物羟化

6α-甲基-11-去氧-17α-羟基-皮质酮-21-乙酸酯(Ⅱ)经短刺克宁汉霉微生物转化得6β-羟基化合物(Ⅵ_a)及6β,11β-羟基化合物(Ⅶ_a)。6α-甲基-17α-羟基-黄体酮(Ⅰ)经短刺克宁汉霉菌转化亦得6β-羟基化合物(Ⅵ_b)及6β,11β-羟基化合物(Ⅶ_b)。化合物(Ⅱ)如用梨头霉转化则得11α-羟化物(Ⅲ)。Ⅶ_a、Ⅶ_b、Ⅷ_a、Ⅷ_b及Ⅺ_b的结构是通过核磁共振谱和质谱证明的。     

海南冬青中的一个新三萜甙

从冬青科植物海南冬青(Ilex hainanensis Merr.)的叶中分离得一新的△¹²-齐墩果叶-烷型的三萜酯甙,甙元的结构为齐墩果叶12-烯23α,28β-二酸3β,16α-二羟基(olean-12-23α,28β-dioic acid 3β,16α-dihydroxyl,Ⅱ),甙的结构为Ⅱ的β-D-葡萄糖(1′→28)酯(β-D-glucopyranosyl(1′→28)ester of Ⅱ),命名为海南冬青甙(hainanenside,Ⅰ)。     

血吸虫病化学治疗的研究 Ⅱ.α-取代-β-(5-硝基-2-呋喃)丙烯酰胺及酯类衍生物的合成

本文报导α-取代-β-(5-硝基-2-呋喃)丙烯酰胺及酯类衍生物85个的合成。这类化合物系分别以糠醛或硝基糠醛与相应的羧酸钾盐经Perkin反应缩合后,按一般方法制成酰胺及酯;或以相应的硝基呋喃丙烯酰胺经溴化;或通过氮内酯中间体经水解、醇解和氨解而制备。经动物篩选后发现有13个化合物对感染日本血吸虫小白鼠有作用,其中α—甲基—β-(5-硝基-2-呋喃)丙烯酰正丁胺(I₆,F-30058),α-甲基-β-(5-硝基-2-呋喃)丙烯酰乙醇胺(I₁₀,F-30141)及α-甲基-β-(5-硝基-2-呋喃)丙烯酰-2′-羟基丙胺(I₁₁,F-30111)三个具有较好抑制作用。     

慢性孵育β-淀粉样肽(25-35)对培养大鼠海马神经元外向钾电流的影响

目的　研究慢性孵育β-淀粉样肽_(25-35) (β-AP_25-35)对海马神经元上瞬时外向钾电流(I_A)和延迟整流钾电流(I_K)的影响。方法　在培养的大鼠海马神经元上用膜片钳全细胞记录钾通道电流。结果　β-AP_25-35 3μmol·L^-1 孵育细胞24h ,I_K 电流幅度增加(44.3±5.4)% ,电流密度由(30.4±6.4)pA·PF^-1 增加至(43.8±4.7)pA·PF^-1 ;β-AP_25-3510μmol·L^-1 孵育12h ,I_K 电流幅度增加(69.8±4.1) % ,电流密度增加至(51.6±7.9)pA·PF^-1,呈浓度依赖性;β-AP_25-35引起的I_K 增加对TEA 5mmol·L^-1 敏感;β-AP_25-35上调I_K 的作用主要发生在β-AP_25-355用药后48h内。β-AP_25-35对I_A无显著性影响。结论　β-AP_25-35选择性地增加海马神经元上I_K,这一作用可能与β-AP的神经毒性有关     

三七绒根中皂甙B1及B2的分离和鉴定

从三七Panax notoginseng(Burk.)F.H.Chen绒根中分得二种微量皂甙,三七皂甙B₁和B₂三七皂甙B₁为一种新皂甙,证明其结构为达玛20(22)-烯3β,12β,25三醇6-O-β-D-葡萄吡喃糖甙(Ⅰ),其皂甙元亦为一种新皂甙元,其结构为达玛20(22)-烯-3β,12β,6 C,25四醇。三七皂甙B₂经鉴定为已知皂甙人参皂甙(ginsenoside—Rh₁,Ⅱ)。     

A new cucurbitacin from Bolbostemma paniculatum Franguent

A new cucurbitacin with an unusual ring A, isocucurbitacin D 25-O-acetate (1), was isolated from Bolbostemma paniculatum Franguent together with one known compound, cucurbitacin E (2). The structure of new compound was established by spectroscopic methods.     

葫芦素B-聚乳酸-羟基乙酸共聚物载药纳米粒的构建与药效学评价

目的 以聚乳酸-羟基乙酸共聚物（PLGA）作为纳米制剂载体材料将葫芦素B制备成纳米粒,并考察其对HepG2肝癌细胞的抑制效果。方法 使用乳化溶剂蒸发法制备葫芦素B-PLGA载药纳米粒,以PLGA浓度（X₁）、PVA浓度（X₂）和药物浓度（X₃）作为考察因素,以载药纳米粒的粒径大小（Y₁）和包封率（Y₂）作为评价指标,应用中心复合设计-效应面法优化葫芦素B-PLGA载药纳米粒处方;测定了纳米粒的粒径分布和Zeta电位值,通过透射电镜观察其微观形态,并考察了葫芦素B-PLGA载药纳米粒的体外药物释放特性;比较了葫芦素B与葫芦素B-PLGA载药纳米粒对HepG2肝癌细胞的抑制效果。结果 葫芦素B-PLGA载药纳米粒的最优处方组成为：PLGA浓度为9.0%,PVA浓度为2.0%,药物浓度为4.5%,制备的纳米粒粒径为（145.4±15.8） nm,Zeta电位值为（-7.6±0.8） mV;透射电镜下可观察到纳米粒表面光滑,分布均匀;葫芦素B-PLGA载药纳米粒释药前期出现突释,后期平缓,48 h药物释放达到86%;葫芦素B-PLGA载药纳米粒对HepG2肝癌细胞的抑制作用显著高于葫芦素B。结论 葫芦素B-PLGA载药纳米粒可延缓药物释放,提高对HepG2肝癌细胞的抑制活性,为进一步临床研究奠定实验基础。     

In vitro and in vivo anticancer properties of cucurbitacin isolated from Cayaponia racemosa

Context: Cucurbitacins are a group of triterpenoids that have a cucurbitane skeleton with a wide range of biological activities.

Objectives: This study evaluated the anticancer properties of one cucurbitacin isolated from Cayaponia racemosa Cong. (Cucurbitaceae), 2β,3β,16α,20(R),25-pentahydroxy-22-oxocucurbita-5-en (1), with in vitro and in vivo models.

Materials and methods: In vitro cytotoxic activity was determined with human leukemia (HL60) and normal blood cells (PBMC). Sarcoma 180 was used as in vivo model.

Results: The cucurbitacin (1) reduced the number of viable cells; however, there was no changed in the number of non-viable cells at 5 µg/mL. Selectivity towards cancer cells was suggested by the absence of activity on normal proliferating lymphocytes at the concentrations tested (IC₅₀ >25 µg/ml). Morphological analysis of compound 1-treated cells showed typical apoptotic features, such as intense deposition of granules in the cytoplasm (eosinophilia), DNA fragmentation and irregularities in the plasma membrane. In addition, the cells treated with compound 1 presented intense vacuolization and disruption of the plasma membrane. Acridine orange/Ethidium bromide staining confirmed these findings, revealing an increased number of apoptotic cells. In the Sarcoma 180 tumor model, compound 1 showed 52 and 62% of antitumor activity, either alone (25 mg/kg/day) or in association with the chemotherapeutic agent 5-FU (10 + 10 mg/kg/day), respectively. Moreover, either alone or associated with 5-FU, treatment with compound 1 caused an increase in spleen weight and morphological alterations related to immunostimulatory properties.

Conclusion: These data indicate that these naturally occurring compounds have anticancer potential.     

Cucurbitacin D isolated from Trichosanthes kirilowii induces apoptosis in human hepatocellular carcinoma cells in vitro

The aim of the present study is to examine the effects of the anti-tumor component isolated from Trichosanthes kirilowii on human hepatocellular carcinoma cells. Using Sephadex G-25 column chromatography, Sep-Pak Plus C18 cartridge and high-performance liquid chromatography (HPLC), we isolated the active component from trichosanthes extract. By fast atom bombardment mass spectrometric analysis, the molecular mass of the active fraction was determined, the active components identified, and their mechanisms of action were analyzed by cell growth assay, cell cycle analysis, TUNEL staining and Western blot analysis. We found that the anti-tumor components isolated from the extract of trichosanthes (EOT) are cucurbitacin D and dihydrocucurbitacin D, and suggest that cucurbitacin D induces apoptosis through caspase-3 and phosphorylation of JNK in hepatocellular carcinoma cells. These results suggest that cucurbitacin D isolated from Trichosanthes kirilowii could be a valuable candidate for anti-tumor drug.     

Modulation of the Megakaryoblastic Dami Cell Line Differentiation by Phosphodiesterase Inhibitors and Imidazo[1,2-a]pyrazine Derivatives

Abstract: Phosphodiesterase inhibitors have been shown to modulate cell differentiation. We have previously shown that a series of imidazo[1,2-a]pyrazine derivatives displayed inhibitory effects on phosphodiesterase isoenzymes types III, IV and V isolated from Dami cells and on Dami cell growth. In the present study we have investigated the effect of these derivatives on the expression of two differentiation markers, glycoproteins Ib and IIb/IIIa of the human megakaryoblastic leukaemic Dami cell line in comparison to those elicited by 3-isobutyl-1-methylxanthine and selective phosphodiesterase inhibitors of types I (8-methoxymethyl-1-methyl-3-(2-methylpropyl) xanthine), III (Milrinone), IV (RO-201724) and V (Zaprinast). Imidazo[1,2-a]pyrazine derivatives, 3-isobutyl-1-methylxanthine and selective phosphodiesterase inhibitors, except 8-methoxymethyl-1-methyl-3-(2-methylpropyl) xanthine, decreased glycoprotein Ib expression. SCA40, SCA41, SCA44 and 3-isobutyl-1-methylxanthine but not the other compounds affected the expression of glycoprotein IIb/IIIa in a positive manner. The effects of imidazo[1,2-a]pyrazine derivatives on glycoprotein expression appeared to be related to their phosphodiesterase inhibitory potency.     

Protective role of exogenous α-lipoic acid (ALA) on hippocampal antioxidant status and memory function in rat pups exposed to sodium arsenite during the early post-natal period

The present work focussed on the effect of exogenous α-lipoic acid (ALA) administration on retention memory and oxidative stress markers in the hippocampus subsequent to early post-natal exposure of rat pups to sodium arsenite (NaAsO₂). Wistar rat pups were divided into the control groups receiving either no treatment (Ia) or distilled water by intraperitoneal route (i.p.) (Ib) and the experimental groups receiving either NaAsO₂ alone (1.5 and 2.0?mg/kg body wt.) (IIa, IIb) or NaAsO₂ (1.5 and 2.0?mg/kg body wt.) followed by ALA (70?mg/kg body wt.) (IIIa, IIIb) (i.p.) from post-natal day (PND) 4–15. The initial and retention transfer latency (ITL and RTL) was determined on PND 14 and 15 using elevated plus maze. The animals were sacrificed by cervical decapitation (PND 16) and the brains were obtained. The dissected out hippocampus was processed for estimation of oxidative stress markers, glutathione (GSH), and superoxide dismutase (SOD). NaAsO₂ exposure resulted in longer RTL in animal groups IIa and IIb, thereby suggestive of arsenic-induced impairment in retention memory. RTL was significantly shorter in animal groups (IIIa, IIIb) receiving ALA following NaAsO₂, thereby suggestive of improvement in retention memory. GSH and SOD levels were significantly decreased in animals receiving NaAsO₂ alone as against group Ib and administration of ALA following NaAsO₂ increased the levels of hippocampal GSH and SOD. These observations are suggestive of the role of exogenous ALA in ameliorating the adverse effects induced by NaAsO₂ exposure of rat pups on retention memory and oxidative stress markers.     

Cucurbitacin B, a novel in vivo potentiator of gemcitabine with low toxicity in the treatment of pancreatic cancer

Background and purpose:

Pancreatic cancer is a highly aggressive malignancy, and improvement in systemic therapy is necessary to treat this frequently encountered metastatic disease. The current targeted agents used in combination with gemcitabine improved objective response rates, but with little or no improvements in survival and also increased toxicities in pancreatic cancer patients. Recently, we showed that the triterpenoid cucurbitacin B inhibited tumour growth in pancreatic cancer cells by inhibition of the JAK/STAT pathway, and synergistically increased antiproliferative effects of gemcitabine in vitro.

Experimental approach:

The anti-tumour effects and toxicities of cucurbitacin B in combination with gemcitabine were tested against human pancreatic cancer cells in a murine xenograft model.

Key results:

Combined therapy with cucurbitacin B and gemcitabine at relatively low doses (0.5 mg·kg⁻¹ and 25 mg·kg⁻¹ respectively) resulted in highly significant tumour growth inhibition of pancreatic cancer xenografts (up to 79%). Remarkably, this therapy was well tolerated by the animals, as shown by histology of visceral organs, analysis of serum chemistry, full blood counts and bone marrow colony numbers. Western blot analysis of the tumour samples of mice who received both cucurbitacin B and gemcitabine, revealed stronger inhibition of Bcl-XL, Bcl-2 and c-myc, and higher activation of the caspase cascades, than mice treated with either agent alone.

Conclusions and implications:

Combination of cucurbitacin B and gemcitabine had profound anti-proliferative effects in vivo against xenografts of human pancreatic cancer cells, without any significant signs of toxicity. This promising combination should be examined in therapeutic trials of pancreatic cancer.     

Aminopeptidase resistant Arg-Gly-Asp analogs are stable in plasma and inhibit platelet aggregation

Tetrapeptides containing the sequence Arg-Gly-Asp (RGD) antagonize fibrinogen binding to its platelet receptor (gp IIb/IIIa, integrin α_11bβ₃) and inhibit platelet aggregation in vitro. The peptides RGDS and RGDY(Me)-NH₂ were rapidly degraded when incubated in human, rat, and dog plasma. HPLC analysis indicated that amino acids were sequentially removed from the peptide N-terminus, and this degradation was prevented by the aminopeptidase inhibitor bestatin. Analogs of RGDY(Me)-NH₂ with an acetylated or deleted α-amino group were prepared. Both analogs were stable when incubated in plasma, blocked ¹²⁵I-fibrinogen binding to activated platelets (IC₅₀= 10–30μm ) and inhibited ADP induced platelet aggregation (IC₅₀= 10–30μm ). This study concludes that aminopeptidase rapidly degrades RGD peptides in plasma, an important issue for in vivo testing of RGD peptides and analogs. RGD analogs intrinsically stabilized against aminopeptidase are stable in plasma and are important tools for antithrombotic studies involving antagonism of gp IIb/IIIa.