鸦胆苦醇合成工艺的研究

鸦胆苦醇具有杀虫止痢和抗疟等功效。可用来治阿米巴痢疾，赘疣、肿瘤等具有较强的抗瘤活性。但其毒性较大，溶解度小，因而，我们以苦醇原料合成具有高效、低毒的苦木内酯类衔生物。     

中药鸦胆子总苦木内酯提取物中鸦胆苦醇的含量测定

目的建立RP HPLC法测定中药鸦胆子总苦木内酯提取物中鸦胆苦醇的含量。方法采用RP HPLC法:色谱柱为C18柱(250 mm×4.6 mm,5μm),流动相为甲醇水(体积比为41∶59),检测波长为277 nm,柱温34℃。结果鸦胆苦醇质量浓度在43.6~348.8 mg.L-1内与峰面积呈良好的线性关系,r=0.999 9(n=5),平均回收率为100.7%,RSD为1.6%(n=9)。结论测定方法准确、可靠,为鸦胆子总苦木内酯提取物质量评价提供了可靠的依据。     

鸦胆子根化学成分的研究

从鸦胆子〔Brucea javanica(L.)Merr.〕根的乙醇提取物中分离得到十二个单体。经理化常数及光谱分析,鉴定了其中的六个化合物:鸦胆苦醇(Brusatol)、没食子酸乙酯(Ethylgallate)、大黄素(Emodin)、大黄酚(Chrysophanol)、大黄酚葡萄糖甙(Chrysophanein)和β-谷甾醇(β-sitosterol)。该六个化合物均系首次从鸦胆子根中得到。     

胆甾烷—3β,5α,6α—三醇3,6—双醋酸酯合成方法的改进

对Ｇｏｔｏ等人制备胆甾烷－３β，５α，６α－三醇３，６－双醋酸酯的新合成路线作了工艺改进，避免使用具腐蚀性及价格昂贵的试剂，简化了操作且收率有所提高。     

鸦胆子抗肿瘤的研究 10.鸦胆子甙A、甙B及鸦胆因E和F的分离与结构鉴定

<正> 继前报,从苦木科植物鸦胆子[Brucea javanica(L.)Merr]的种子中分离出三个单体,即鸦胆子苦醇,鸦胆因 D 和鸦胆因 B 后,又进一步从该种子的有效的丁醇提取物中分离得到四个苦木内酯类单体,经鉴定证明分别为鸦胆子甙 A(Bruceoside A),甙 B(Bruceo-side B),鸦胆因 E(Bruceine E)和 F(Bruceine F),据报导鸦胆子甙 A     

胆骨化醇与钙三醇治疗肾衰继发甲状旁腺机能亢进的对比研究

目的 比较胆骨化醇与钙三醇治疗肾衰长期透析患者继发性甲状旁腺机能亢进的疗效.方法随机分为胆骨化醇组31例,肌注胆骨化醇60万U,每周1次,血钙正常后改为每2周1次;钙三醇组33例,口服钙三醇 0.25 μg·d-1.两组分别于用药前及用药后2、4、8 wk 采用高效液相层析仪检测患者血1,25(OH)2D3浓度,用放射免疫法检测患者血清免疫甲状旁腺激素(iPTH)浓度,以及血钙、血磷、血碱性磷酸酶(ALP)等.结果1,25(OH)2D3浓度胆骨化醇组用药2 wk时升高,但未达正常水平,钙三醇组达正常水平(P＜0.05);治疗4 wk时两组均达正常水平.血钙、磷、ALP浓度的变化两组无明显差异.结论胆骨化醇组未出现高钙血症及钙磷乘积升高,以其用药次数少、价格低廉、安全有效而优于钙三醇.     

苦山柰化学成分的研究

目的　研究中药山柰的混杂品种苦山柰Kaempferia marginata Carey的化学成分。方法　利用色谱技术进行分离纯化, 根据化合物的理化性质和光谱数据进行结构鉴定。结果　从苦山柰的根茎分得苦山柰萜醇(1)、8(14),15-sanderacopimaradiene-1α,9α-diol (2)、8(14),15-sanderacopimaradiene-1α,6β,9α-triol (3)、吉马酮(4)、对-甲氧基-肉桂酸乙酯(5)和正-十五烷(6)。结论　苦山柰萜醇(1)为新二萜醇, 化学结构为8(14),15-isopimaradiene-6α-ol。2, 3和4是首次从该植物中分得。     

苦山柰的二萜化学成分(英文)

从中药山柰的混杂品种苦山柰根茎分得一个新二萜苦山柰萜醇(marginatol 1) 和5个已知化合物：8(14),15-sanderacopimaradiene-1α,9α-diol(2), 8(14),15 -sanderacopimaradiene-1α,6β,9α-triol(3) 以及吉马酮(4), 对-甲氧基-肉桂酸乙酯(5) 和正-十五烷(6)。根据光谱数据(IR, MS, 1H-1H, 13C-1H NMR, NOESY 和 HMBC) 分析,确定苦山柰萜醇(1)的化学结构为8(14),15-isopimaradiene-6β-ol。化合物2,3 和 4是首次从该植物分得。     

维生素D在神经系统中的作用研究进展

维生素D主要包括维生素D2(麦角骨化醇)和维生素D3胆骨化醇。人体内维生素D主要来源是紫外线照射皮肤,由皮肤基底层的7-脱氢胆骨化醇转化为胆骨化醇,也可以通过食物获取一部分。其生化作用通过肝脏和肾脏羟化形成活性代谢产物1,25二羟基维生素D3[1,25(OH)2D3]实现。     

鸦胆子油的提取

鸦胆子为苦木科植物鸦胆子的果实，别名有鸦胆、老鸦胆、苦棒子、苦参子、鸦蛋子、鸭蛋子、解苦庆、小苦探等。含有生物碱（鸦胆子往、鸦胆宁）、糖忒（鸦胆灵、鸦胆子成）、酚性成分（鸦胆子酚）及鸦胆子苦醇、鸦胆子素等苦味成分。鸦胆子仁含脂肪油（鸦胆子抽56·23％）。现将鸦胆子油的提取方法介绍如下．鸦胆子油的提取一般常用压榨法和溶剂提取法两种，而后者所得的鸦胆子抽纯度高，本实验采用泡剂提取法。1．实验的原料、试剂：鸦胆子：市药材站出售、本省闽北产的苦木材植物的果实。石油酸：上海产，化学纯（因购不到工业用的），佛…     

Effects of dexamethasone on [3H]choline uptake by rat forebrain synaptosomes

Summary Dexamethasone (3–300 mol/l) did not affect uptake of choline (1 mol/l) by rat forebrain isolated nerve terminals (crude synaptosomal fraction). At concentrations which have been shown to increase choline uptake by rat superior cervical ganglion, dexamethasone had no effect on synaptosomal choline uptake at choline concentrations between 0.1 and 30 mol/l, nor on choline uptake which had been partially inhibited either by hemicholinium-3 (0.1 mol/l) or by reducing the NaCl concentration (0-140 mmol/l).     

Activation of β2-adrenoceptors by isoprenaline and adrenaline enhances noradrenaline release in cortical kidney slices of young spontaneously hypertensive rats

Summary The aim of the present study was to investigate -adrenoceptor modulation of noradrenaline release from sympathetic nerves in superfused cortical kidney slices of 4-week-old spontaneously hypertensive rats (SHR) and age-matched controls (WKY). After preincubation with ³H-noradrenaline the kidney slices were electrically stimulated in superfusion chambers. The stimulation induced (S-I) outflow of radioactivity was mainly composed of unmetabolized 3H-noradrenaline in both strains and thus taken as an index of noradrenaline release. There was a frequency-dependent (1.25–20 Hz) increase in the S-1 outflow of radioactivity. At all stimulation frequencies tested S-I outflow of radioactivity was similar or even slightly lower in SHR than in WKY kidney slices in either the absence or presence of cocaine (10 mol/l). The non-selective -adrenoceptor agonists isoprenaline (0.l gmol/1) and adrenaline (0.01 and 0.1 mol/l) enhanced S-I outflow of radioactivity. The facilitatory effects of isoprenaline (0.1 mol/l) and adrenaline (0.1 mol/l) were blocked by the selective ₂-adrenoceptor antagonist ICI 118551 (0.1 mol/l) but not by the selective ₁-adrenoceptor antagonist atenolol (0.3 mol/l). The cell-permeable CAMP analogue 8-bromo-cAMP (300 mol/l) enhanced S-1 outflow of radioactivity to a similar extent in both SHR and WKY kidney slices. A combination of 8-bromo-cAMP (300 mol/l) and adrenaline (0.1 mol/l) did not enhance S-1 outflow of radioactivity to a greater extent than 8-bromo cAMP (300 mol/l) alone in both strains. However, the facilitatory effects of isoprenaline (0.1 mol/l) and adrenaline (0.1 mol/l) but not that of adrenaline (0.01 mol/l) were significantly greater in SHR than in WKY. The results suggest that stimulation of prejunctional ₂-adrenoceptors by adrenaline even in the absence of a-adrenoceptor blockade enhances noradrenaline release in kidney cortex of young SHR and WKY. This ₂-adrenoceptor mediated effect may possibly be dependent on cAMP formation. The greater facilitatory effects of isoprenaline (0.1 mol/l) and adrenaline (0.1 mol/l) in SHR as compared to WKY are in accord with receptor binding studies which show a higher density of ₂-adrenoceptors in SHR than in WKY kidney cortex.Abbreviations SHR Spontaneously hypertensive rats - WKY WistarKyoto rats - cAMP 3-5-cyclic adenosine monophosphate - S-I stimulation induced Send offprint requests to: L. C. Rump     

Dual inhibition of STAT1 and STAT3 activation downregulates expression of PD-L1 in human breast cancer cells

Objectives: Breast cancer is the most commonly diagnosed cancer, and it is a leading cause of cancer-related deaths in females worldwide. Triple-negative breast cancer (TNBC) constitutes 15% of breast cancer and shows distinct metastasis profiles with poor prognosis. Strong PD-L1 expression has been observed in some tumors, supporting their escape from immune surveillance. Targeting PD-L1 could be a promising therapeutic approach in breast cancer patients. We investigated potential molecular mechanisms for constitutive expression of PD-L1 by inhibiting upstream STAT1 and STAT3 signals.

Methods: PD-L1 expression in three breast cancer cell lines was measured using quantitative PCR and western blotting. Activation of STAT1 and STAT3 was blocked using pharmacological inhibitors and siRNA. The mechanism underlying the constitutive expression of PD-L1 was investigated using ChIP and co-immunoprecipitation assays.

Results: We found that individual inhibition of STAT1 and STAT3 activation partially downregulated PD-L1, while combined inhibition completely downregulated PD-L1 expression. Moreover, our results suggest that pSTAT1-pSTAT3 dimerize in cytosol and translocate to the nucleus, where they bind to PD-L1 promoter and induce PD-L1 expression.

Conclusion: These findings provide a rationale for combined targeting of STAT1 and STAT3 for the development of immune-based cancer therapies for down regulation of PD-L1 expression.     

Mechanistic kinetic modeling generates system-independent P-glycoprotein mediated transport elementary rate constants for inhibition and,in combination with 3D SIM microscopy,elucidates the importance of microvilli morphology on P-glycoprotein mediated efflux activity

Introduction: In vitro transporter kinetics are typically analyzed by steady-state Michaelis-Menten approximations. However, no clear evidence exists that these approximations, applied to multiple transporters in biological membranes, yield system-independent mechanistic parameters needed for reliable in vivo hypothesis generation and testing.

Areas covered: The classical mass action model has been developed for P-glycoprotein (P-gp) mediated transport across confluent polarized cell monolayers. Numerical integration of the mass action equations for transport using a stable global optimization program yields fitted elementary rate constants that are system-independent. The efflux active P-gp was defined by the rate at which P-gp delivers drugs to the apical chamber, since as much as 90% of drugs effluxed by P-gp partition back into nearby microvilli prior to reaching the apical chamber. The efflux active P-gp concentration was 10-fold smaller than the total expressed P-gp for Caco-2 cells, due to their microvilli membrane morphology. The mechanistic insights from this analysis are readily extrapolated to P-gp mediated transport in vivo.

Expert opinion: In vitro system-independent elementary rate constants for transporters are essential for the generation and validation of robust mechanistic PBPK models. Our modeling approach and programs have broad application potential. They can be used for any drug transporter with minor adaptations.     

Inhibition of 5-HT3 receptor function by imidazolines in mouse neuroblastoma cells: potential involvement of σ2 binding sites

The influence of several imidazolines and -site ligands on cation influx through the 5-HT₃ receptor channel in NIE-115 mouse neuroblastoma cells was studied by measuring the 2-min influx of the organic cation [¹⁴C] guanidinium induced by 1 M 5-HT (in the presence of 10 M substance P in all experiments). In addition, we determined specific binding of [³H]DTG (1,3-di(2-tolyl)-guanidine), a selective -site radioligand, and [³H] GR65630 (3-(5-methyl-1H-imidazol-4-yl)-1-(1-methyl-1H-indol-3-yl)-1-propanone), a selective 5-HT₃ receptor antagonist, to membranes prepared from NIE-115 cells.The 5-HT-induced [¹⁴C]guanidinium influx was inhibited by the imidazolines, ondansetron, antazoline, idazoxan, BDF 6143 (4-chloro-2-(2-imidazolin-2-ylamino)-isoindoline), cirazoline, naphazoline, clonidine and by the guanidine agmatine, but not by the catecholamine adrenaline. The inhibitory effect of the imidazolines on cation influx through the 5-HT₃ receptor channel was mimicked by the -site ligands, (±)-ifenprodil, (+)-3-PPP ((R)-3-(3-hydroxyphenyl)-N-propylpiperidine), DTG (1,3-di-tolyl-guanidine), haloperidol, dizocilpine, and ketamine as well as by the polyamines, arcane and spermidine. — Ondansetron inhibited [³H]GR65630 binding with high affinity, whereas inhibition of binding of this radioligand to the 5-HT₃ receptor by antazoline, BDF 6143, idazoxan, cirazoline, (±)-ifenprodil, (+)-3-PPP, DTG and haloperidol occurred in the high micromolar range. In the competition experiments with [³H]DTG, (±)-ifenprodil, haloperidol, unlabelled DTG, BDF 6143 and (+)-3-PPP inhibited binding of the radioligand at moderate affinity (K_i values in the range of 1 M or lower), whereas ondansetron, amazoline, idazoxan, cirazoline, naphazoline, clonidine, tolazoline, efaroxan, RX821002 (2-[2-(2-methoxy-1,4-benzodioxanyl)]imidazoline), ketamine and spermidine exhibited affinity in the high micromolar or millimolar range only. Comparison of the potencies of the ligands (pIC_50% values) in inhibiting 5-HT-induced [¹⁴C]guanidinium influx with their affinities (pK_i values) at the 5-HT recognition sites of the 5-HT₃ receptor and at the ₂-sites of the N1E-115 cells by means of multiple regression analysis revealed a significant correlation with the affinities at both sites.In conclusion, our data suggest that imidazolines and -ligands, which as a rule possess low affinity for the 5-HT recognition site of the 5-HT₃ receptor, may be assumed to exert their inhibitory effect on cation influx through the 5-HT₃ receptor channels, at least in part, by interacting with ₂-binding sites.     

Targeting protein kinase-b3 (akt3) signaling in melanoma

Introduction: Deregulated Akt activity leading to apoptosis inhibition, enhanced proliferation and drug resistance has been shown to be responsible for 35–70% of advanced metastatic melanomas. Of the three isoforms, the majority of melanomas have elevated Akt3 expression and activity. Hence, potent inhibitors targeting Akt are urgently required, which is possible only if (a) the factors responsible for the failure of Akt inhibitors in clinical trials is known; and (b) the information pertaining to synergistically acting targeted therapeutics is available.

Areas covered: This review provides a brief introduction of the PI3K-Akt signaling pathway and its role in melanoma development. In addition, the functional role of key Akt pathway members such as PRAS40, GSK3 kinases, WEE1 kinase in melanoma development are discussed together with strategies to modulate these targets. Efficacy and safety of Akt inhibitors is also discussed. Finally, the mechanism(s) through which Akt leads to drug resistance is discussed in this expert opinion review.

Expert opinion: Even though Akt play key roles in melanoma tumor progression, cell survival and drug resistance, many gaps still exist that require further understanding of Akt functions, especially in the (a) metastatic spread; (b) circulating melanoma cells survival; and (c) melanoma stem cells growth.     

Plasma concentration of α-methyldopa and sulphate conjugate after oral administration of methyldopa and intravenous administration of methyldopa and methyldopa hydrochloride ethyl ester

Summary The plasma concentrations of free -methyldopa and methyldopa sulphate conjugate were measured in 7 hypertensive patients with normal renal function following -methyldopa (1 g) orally. Five of these patients subsequently received -methyldopa ethyl ester (250 mg) (methyldopate) intravenously and two further patients received 250 mg of -methyldopa intravenously. After oral administration a large amount of total plasma -methyldopa was present as sulphate conjugate. There were wide interindividual differences in the ratio of free: conjugated -methyldopa in plasma (ratio at 4 hours ranged from 3.73 – 0.83) suggesting that individual differences in the extent of sulphate conjugation may occur. There was no close correlation between the degree of conjugation and the fall in arterial pressure. At all time intervals examined, plasma concentrations were higher following intravenous -methyldopa than -methyldopate. The plasma concentration of -methyldopa (free and esterified) 60 minutes after i.v. -methyldopate was 1.7±0.3 µg/ml wile at the same time after the same dose of methyldopa by the same route the mean concentration was 5.9 µg/ml. Although small amounts of sulphate conjugate were detected after i.v. -methyldopate, insignificant quantities of conjugate were found after i.v. -methyldopa. The average fall in mean arterial pressure was 27 mm Hg following i.v. -methyldopa but only 2.7 mm Hg following -methyldopate. These results suggest that sulphate conjugation of -methyldopa occurs in the gastrointestinal tract during absorption. Hydrolysis of -methyldopa ethyl ester does not appear to be instantaneous and pharmacokinetic differences between the ester and free -methyldopa have been demonstrated.     

Therapeutic inhibition of BCL-2 and related family members

Introduction: BCL-2 proteins are key players in the balance of cell life and death. Their roles in the development and biology of cancer have been well established and continue to be investigated. Understanding the mechanisms by which these proteins regulate apoptosis has led to the development of small molecule targeted therapies that act to overcome the cell’s ability to evade programmed cell death.

Areas covered: The biology of the intrinsic apoptotic pathway is reviewed with attention to the varied roles of the anti-apoptotic members of the BCL-2 family. BH3 profiling is reviewed. Historical therapeutic agents are addressed, and currently investigated BH3 mimetics are described with attention to clinical significance. The limitations of BCL-2 family targeted drugs with regard to on-target and off-target toxicities are explored. Agents under development for targeting MCL-1 and other BCL-2 family members are discussed.

Expert opinion: ABT-199 (venetoclax) and other BH3 mimetics have entered the clinical arena and show promising results in both hematologic and solid malignancies. Use of agents targeting this system will likely expand, and likely a number of malignant diseases will be successfully targeted resulting in improved treatment responses and patient survival.