狭叶藜芦中活性成分的化学研究

我们从狭叶藜芦(Veratrum stenophyllum)中分得14个化合物(V_1-V_(14)),其中8个鉴定为已知化合物,1个的结构待定,测定了狭叶藜芦硷甲(V_3)、硷乙(V_6)(stenophylline A, B)和β_1-chaconine(V_(12))的结构,推定了狭叶藜芦硷丙(V_(10))和硷丁(V_(14))     

去纤酶无直接溶栓作用

在以贫含血小板血浆为媒介的体外溶栓模型上,尿激酶(5×10~5～5×10~6IU·L~(-1))作用30min使人造混合血栓的重量呈剂量依赖性的降低。剂量为2×10~6IU·L~(-1)时,作用达峰值。相反,去纤酶(6.25～25IU·L~(-1))使血栓重量呈剂量相关性的增加。用大剂量凝血酶(1×10~5IU·L~(-1))消耗媒介中的纤维蛋白原后,去纤酶不再增加血栓重量,与生理盐水相比,亦未见有明显的降低血栓重量的作用。本结果提示去纤酶无直接溶栓作用。     

智利小檗胺的新合成

(±)智利小檗胺((±)-chilenamine(1))是一种新类型的异吲哚苯并氮杂草结构生物碱,为达尔文小檗(Berberis darwiinii)中的一种成分。作者通过游离基环化反应以6-溴-2,3-二甲氧基苯甲醛(5)和3,4-次甲二氧基苯乙胺(6)为原料经N-取代苯并氮杂(艹卓)(10)合成了(1)。 (5)和(6)于二氯甲烷中在分子筛的存在     

辽东楤本化学成分的研究

从辽东楤本(Aralia elata)的根皮中分得8个化合物,利用理化和光谱方法鉴定分别为胡萝卜甙-6’-棕榈酸酯(6’-O-palmitoyl-β-sitosterol-3-O-β-D-glucoside,A_5)、罗盘草甙A(silphioside A,A_9)、楤木皂甙A甲酯(araloside A methyl ester,A_(10))、竹节人参甙I_b(chikusetusaponin I_b,A_(11))、楤木皂甙A(araloside A,A_(12))、楤木皂甙C(araloside C,A_(15)、楤木皂甙G(araloside G,A_(16))、无梗五加甙D(acanthoside D,B_1)。化合物A_5,A_9,A_(11)和B_1为首次从该植物中分得,A_(10)为新天然产物,A_(16)为新化合物命名为楤木皂甙G,归属了化合物A_9,A_(15)的~(13)C-NMR化学位移。     

6-O-酰化胞壁酰二肽能增强小鼠对HBsAg、流感病毒血凝素和破伤风类毒素的IgG应答

本文比较了三种具有6-O-酸基-酰基团的胞壁酰二肽(MDP)类似物〔6-O-C_(14)-O-(C_(16))-(MDP)(Me)、6-O-C_(14)-O-(C_(12))-(MDP)(Me)和6-O-C_(14)-O-(C_(14))-(MDP)(Me)〕水溶液的佐荆活性,以6-O-B30-MDP为阳性对照.将佐剂(100μg/mg)分别与HBsAg(100μg/mg)、流感病毒血凝素疫苗(9μg/ml)或破伤风类毒素(31μg/ml)等体积混合作为免疫抗原,对8～10周龄CDF1小鼠作腹腔注射(每组8只,每只0.2ml),3周后进行加强免疫.从眼眶后静脉或心脏采血,用ELISA法测定血清中IgG滴度.     

锦熟黄杨制剂(SPV_(30))对感染HIV的无症状病人的疗效和安全性

锦熟黄杨为法国药典第10版收载,它含有黄酮类化合物和多种甾体生物碱。作者报道了锦熟黄杨制剂(SPV_(30))多中心、双盲和安慰剂对照的临床观察结果。145名 HIV 感染无症状且未曾治疗过、CD_4细胞数为250×10~6～500×10~6/L 及年龄不低于18岁的病人进行随机双盲试验,通     

白杨素对TNF-α诱导慢性暴露TGF-β卵巢癌OVCAR-3细胞系球形成的影响

目的研究白杨素对肿瘤坏死因子-α(TNF-α)诱导慢性暴露转化生长因子-β(TGF-β)卵巢癌OVCAR-3细胞系球形成的影响,并探讨其作用机制是否涉及下调NF-κB(p65)蛋白表达。方法 TNF-α(10μg·L~(-1))处理TGF-β(5μg·L~(-1))预暴露12 d的卵巢癌OVCAR-3细胞24 h,球形成率测定法检测不同浓度(5.0、10.0、20.0μmol·L~(-1))白杨素对球形成率的影响;Western blot检测NF-κB(p65)蛋白表达;NF-κB(p65)siRNA转染探讨作用机制。结果 TNF-α(10μg·L~(-1))联合慢性暴露TGF-β(5μg·L~(-1))处理增高OVCAR-3细胞系球形成率。白杨素能有效地拮抗致炎因子诱导卵巢癌细胞自我更新作用,呈剂量依赖性(P<0.05),并伴随着NF-κB(p65)蛋白表达下调。与对照siRNA相比,NF-κB(p65)siRNA转染OVCAR-3细胞NF-κB(p65)蛋白表达下调,并明显增强白杨素抑制球形成作用。结论下调NF-κB(p65)蛋白表达参与白杨素抑制TNF-α(10μg·L~(-1))联合慢性暴露TGF-β(5μg·L~(-1))处理诱导卵巢癌OVCAR-3细胞系球形成作用。     

丹参素对糖皮质激素诱导骨丢失大鼠胫骨近端骨密度和骨微结构的影响北大核心CSCD

目的探讨丹参素对糖皮质激素诱导骨丢失大鼠胫骨近端骨密度和骨微结构的影响。方法 60只7月龄SPF级♀SD大鼠按体质量随机分为6组,每组10只:空白对照组(生理盐水:5 mL·kg^(-1)·d^(-1))、糖皮质激素模型组(醋酸泼尼松:6 mg·kg^(-1)·d^(-1))、糖皮质激素+丹参素低剂量组(12.5 mg·kg^(-1)·d^(-1))、糖皮质激素+丹参素中剂量组(25mg·kg^(-1)·d^(-1))、糖皮质激素+丹参素高剂量组(50 mg·kg^(-1)·d^(-1)),糖皮质激素+(阳性对照药)骨化三醇组(0.045μg·kg^(-1)·d^(-1))。采用醋酸泼尼松连续灌胃14周建立大鼠骨丢失模型,同时采用丹参素和骨化三醇灌胃给药进行干预。实验结束后,取左侧胫骨近端进行Micro-CT扫描并分别对皮质骨和松质骨进行三维重建,观察骨微结构并检测骨密度等相关参数。结果糖皮质激素可引起大鼠胫骨近端骨密度下降,骨微结构异常。给予中剂量丹参素和骨化三醇均可提高骨密度并改善骨微结构,且二者效果相当;高剂量丹参素对骨微结构有一定程度的改善,但对骨密度无明显改变;低剂量丹参素对骨密度和骨微结构均无明显改善。结论丹参素(25 mg·kg^(-1)·d^(-1))灌胃给药可预防糖皮质激素引起的大鼠胫骨近端骨密度下降和骨微结构异常。     

丹参素对糖皮质激素诱导骨丢失大鼠胫骨近端骨密度和骨微结构的影响

目的探讨丹参素对糖皮质激素诱导骨丢失大鼠胫骨近端骨密度和骨微结构的影响。方法 60只7月龄SPF级♀SD大鼠按体质量随机分为6组,每组10只:空白对照组(生理盐水:5 mL·kg~(-1)·d~(-1))、糖皮质激素模型组(醋酸泼尼松:6 mg·kg~(-1)·d~(-1))、糖皮质激素+丹参素低剂量组(12.5 mg·kg~(-1)·d~(-1))、糖皮质激素+丹参素中剂量组(25mg·kg~(-1)·d~(-1))、糖皮质激素+丹参素高剂量组(50 mg·kg~(-1)·d~(-1)),糖皮质激素+(阳性对照药)骨化三醇组(0.045μg·kg~(-1)·d~(-1))。采用醋酸泼尼松连续灌胃14周建立大鼠骨丢失模型,同时采用丹参素和骨化三醇灌胃给药进行干预。实验结束后,取左侧胫骨近端进行Micro-CT扫描并分别对皮质骨和松质骨进行三维重建,观察骨微结构并检测骨密度等相关参数。结果糖皮质激素可引起大鼠胫骨近端骨密度下降,骨微结构异常。给予中剂量丹参素和骨化三醇均可提高骨密度并改善骨微结构,且二者效果相当;高剂量丹参素对骨微结构有一定程度的改善,但对骨密度无明显改变;低剂量丹参素对骨密度和骨微结构均无明显改善。结论丹参素(25 mg·kg~(-1)·d~(-1))灌胃给药可预防糖皮质激素引起的大鼠胫骨近端骨密度下降和骨微结构异常。     

紫蜂斗菜标准提取物制剂Petadolex~((R))防治偏头痛的多中心临床试验

作者采用随机、双盲、三分组、平行设计、安慰剂对照的方法,研究了Petadolex~((R))对偏头痛的防治作用。Petadolex~((R))是紫蜂斗菜Petasites hybridus(L.)根的标准提取物,至少含15％蜂斗精和异蜂斗精,且对肝有毒性的吡咯双烷类生物碱(PAs)含量不得超过0.01×10~(-6) 试验持续20周,前4周为基线期,后16     

Effective mast cell degranulating peptide inhibitors of the IgE/Fc epsilonRI receptor interaction

Previous studies with mast cell degranulating (MCD) peptide have shown that peptide [Ala(12)]MCD 8 was an inhibitor of IgE binding to mast cell receptors. In an attempt to produce increased inhibition, analogs were synthesized that maintained the alanine residue in position 12 in the MCD peptide sequence and were further modified at both termini. Analogs modified at the C-terminus were [Ala(12),desLys(21)]MCD 2 and [Ala(12),D-Lys(21)]MCD 4. N-terminus modifications were [desLys(6)-Arg(7)-His(8),Ala(12)]MCD 1, [Ala(6), Ala(12)]MCD 6, and [Val(6),Ala(12)]MCD 7. To assess the role of the Proline(12), analogs [D-Ala(12)]MCD 3 and [Meleu(12)]MCD 5 were also synthesized. The analogs were tested for binding to the IgE receptor in cultured mast cells. Inhibitory activity of IgE-caused degranulation was measured using a beta-hexosaminidase assay. Circular dichroism (CD) and molecular modeling of selected analogs were used to follow possible structural differences among these analogs. All analogs showed binding affinity to the IgE receptor and inhibition of IgE-induced mast cell degranulation at different levels. Differences in inhibition were most likely because of diverse interactions of the analogs with the receptor as inferred by the CD and modeling studies. Based on the results of the beta-hexosaminidase assay, analog [Val(6), Ala(12)]MCD 7 proved to be an excellent inhibitor of IgE-mediated mast cell degranulation.     

Structure-activity relationship of neurokinin A(4-10) at the human tachykinin NK(2) receptor: the effect of amino acid substitutions on receptor affinity and function

A structure-activity study of the neurokinin A (NKA) fragment NKA(4-10) was performed to investigate the importance of amino acid residues for receptor efficacy, potency and affinity at the NK(2) receptor in human colon circular muscle. Fourteen analogs of NKA(4-10) were produced with substitutions at positions 4, 5, 7, 9 and/or 10 of NKA. Their potencies were determined by in vitro contractile responses and affinities by radioligand binding using [125I]NKA. Functional potency was enhanced 8-fold by single amino acid substitutions with Lys(5) and MeLeu(9) but not significantly altered by substitutions Glu(4), Arg(5), His(5) and Nle(10). The multiply-substituted analogs [MeLeu(9),Nle(10)]NKA(4-10), [Lys(5),MeLeu(9),Nle(10)]NKA(4-10) and [Lys(5),(Tyr(7)),MeLeu(9),Nle(10)]NKA(4-10) displayed 6-9-fold increase in potency. Although [Arg(5),Nle(10)]NKA(4-10) was similar in potency to NKA(4-10), it was the only analog to show significantly reduced efficacy. All analogs were able to compete fully for [125I]NKA binding. [Lys(5),MeLeu(9)]NKA(4-10), [MeLeu(9),Nle(10)]NKA(4-10), [Lys(5),Nle(10)]NKA(4-10) and analogs containing single substitutions with Glu(4), Arg(5), Lys(5) and MeLeu(9) displayed significantly higher affinity, whereas those with Nle(10) and [Glu(4),Nle(10)] substitutions showed significantly lower affinity than NKA(4-10). There was a positive correlation (r=0.63) between binding affinity and functional potency, which was markedly improved (r=0.95) by removal of three analogs: [Lys(5),MeLeu(9),Nle(10)]NKA(4-10), [Lys(5),Tyr(7),MeLeu(9),Nle(10)]NKA(4-10) and [Lys(5),Tyr(I(2))(7),MeLeu(9),Nle(10)]NKA(4-10). These exhibited similar binding affinities to that of NKA(4-10) but were more potent in functional studies, possibly indicating a different mechanism of receptor interaction. In conclusion, substitution of Ser(5) with Lys, and/or N-methylation of Leu(9), were the most effective changes to increase functional and binding potency of NKA(4-10) at the human colon NK(2) receptor.     

Kinetics of formation for lanthanide (III) complexes of DTPA-(Me-Trp)2 used as imaging agent

Diethlenetriamine-N,N,N'N'N'-pentaacetic acid (DTPA)-bis (amide) analogs have been synthesized and evaluated as a potential biomedical imaging agents. Imaging and biodistribution studies were performed in mice that showed a significant accumulation of DTPA analogs in brain. The stability and protonation constants of the complexes formed between the ligand [DTPA-(Me-Trp)(2)] and Gd(3+), Eu(3+), and Cu(2+) have been determined by pH potentiometry (Gd(3+), Eu(3+)) and spectrophotometry (Cu(2+)) at 25 °C and at constant ionic strength maintained by 0.10 M KCl. The kinetic inertness of Gd [DTPA-(Me-Trp)(2)] was characterized by the rates of exchange reactions with Zn(2+) and Eu(3+). In the Eu(3+) exchange, a second-order [H(+)] dependence was found for the pseudo-first-order rate constant [k(0) = (4.5 ± 1.2) × 10(-6)/s; k(1) = 0.58 ± 0.1 /M/s, k(2) = (6.6 ± 0.2) × 10(4) /M(2)/s, k(3) = (4.8 ± 0.8) × 10(-4) /M/s]. In the Eu(3+) exchange, at pH <5.0, the rate decreases with increasing concentration of the exchanging ion. At physiological pH, the kinetic inertness of [DTPA-(Me-Trp)(2)] is more inert than GdDTPA(2-), the most commonly used MRI contrast agent (t(1/2) = 127 h). High kinetic stability is an important requirement for the Gd complexes used as contrast enhancement agents in magnetic resonance imaging.     

Analogs of luteinizing hormone-releasing hormone with increased biological activity produced by D-amino acid substitutions in position 6.

The incorporation of simple d-amino acids in place of glycine in position 6 of the LH-RH decapeptide produces analogs which have far greater gonadotropin-releasing activities in vivo and in vitro than the natural hormone. An investigation of the structural features of the d-amino acids responsible for this phenomenon suggests that an increase in the lipophilic character and perhaps the size and aromaticity of the side chain coincides with an increase in biological activity. This is demonstrated by the LH-releasing activities of the following series of peptides which were assayed over a period of 6 h in immature male rats: [d-Glu(6)]-,1.8;[d-Ala(6)]-,7.0;[d-Leu(6)]-,9,0;[d-Phe(6)]-,10;[d-Trp(6)]-LH-RH, 13 times more active than LH-RH itself. In contrast to previous results with [d-Ala(6)]-and [d-Leu(6)]-LH-RH, where the substitution of an ethylamide group for the glycine amide at the C-terminus produces large increases in LH/FSH releasing activity, the ethylamide derivatives of [d-Phe(6)]-and [d-Trp(6)]-LH-RH were actually less potent than their parent peptides. [(N-Me-d-Ala)(6)]-LH-RH was found to be approximately 70 times less active than [d-Ala(6)]-LH-RH which indicates that disruption of a preferred receptor-site binding conformation might be brought about by methylation of the amide linkage in this position.     

Importance of the aromatic residue at position 6 of [Nle(10)]neurokinin A(4-10) for binding to the NK-2 receptor and receptor activation.

Steric and electrostatic requirements at position 6 of [Nle(10)]NKA(4-10), a full agonist of NK-2 receptors, for molecular recognition by the receptor were studied. Two series of peptide analogues, (a) p-substituted analogues, [p-X-Phe(6), Nle(10)]NKA(4-10), where X = F, Cl, Br, I, NH(2), NO(2), and (b) [D-Phe(6),Nle(10)]NKA(4-10), [Trp(6),Nle(10)]NKA(4-10), and [Chex-Ala(6),Nle(10)]NKA(4-10), were synthesized, and their biological activity was examined. Competition binding experiments with [(3)H]NKA were performed using cloned human NK-2 receptors expressed in CHO cells. Antagonistic and agonistic properties of the analogues were studied using an in vitro functional assay with hamster tracheal rings. The rank order of potency of agonists was [Nle(10)]NKA(4-10) approximately [p-F-Phe(6),Nle(10)]NKA(4-10) > [p-NH(2)-Phe(6),Nle(10)]NKA(4-10) > [p-Cl-Phe(6),Nle(10)]NKA(4-10) > [p-NO(2)-Phe(6),Nle(10)]NKA(4-10) > [Trp(6),Nle(10)]NKA(4-10). Size and planarity of the aromatic side chain were crucially important for the biological activity, whereas electron-donating and electron-withdrawing properties of the para-substituent were less important. The results favor the hypothesis that weakly polar pi-pi interactions exist between the aromatic group and the receptor.     

Modulation of the hydrophobic domain of polymyxin B nonapeptide: effect on outer-membrane permeabilization and lipopolysaccharide neutralization

Polymyxin B nonapeptide (PMBN), a cationic cyclic peptide derived from the antibacterial peptide polymyxin B, is capable of specifically increasing the permeability of the outer membrane (OM) of Gram-negative bacteria toward hydrophobic antibiotics. In this study, we evaluated the contribution of the hydrophobic segment of PMBN (i.e., D-Phe(5)-Leu(6)) to this activity. Accordingly, we synthesized four analogs of PMBN by replacing D-Phe(5) with either with D-Trp or D-Tyr and Leu(6) with Phe or Ala and evaluated their ability to bind cell-free lipopolysaccharide (LPS) and increase bacterial OM permeability. Compared with PMBN, [D-Tyr(5)]PMBN and [Ala(6)]PMBN possessed reduced LPS affinity (IC(50) = 2.5, 25, and 12 microM, respectively) and significantly reduced OM permeability and LPS neutralization activity. [Phe(6)]PMBN exhibited rather similar affinity to cell-free LPS (IC(50) = 5 microM) and the same OM permeability capacity as PMBN. However, [D-Trp(5)]PMBN, despite its similar affinity to cell-free LPS (IC(50) = 4 microM), had moderately reduced OM permeability capacity. These results demonstrate the significant role of the PMBN hydrophobic segment in promoting biological activity.     

Creation of a selective antagonist and agonist of the rat VPAC(1) receptor using a combinatorial approach with vasoactive intestinal peptide 6-23 as template

We have used combinatorial chemistry with amino acid mixtures (X) at positions 6 to 23 in vasoactive intestinal peptide (VIP) to optimize binding affinity and selectivity to the rat VPAC(1) receptor. The most efficient amino acid replacement was a substitution of alanine at position 18 to diphenylalanine (Dip), increasing the displacement efficiency of (125)I-VIP by 370-fold. The [Dip(18)]VIP(6-23) was subsequently used to find a second replacement, employing the same approach. Tyrosine at position 9 was selected and the resulting [Tyr(9),Dip(18)]VIP(6-23) analog has a K(i) value of 90 nM. This analog was unable to stimulate cAMP production at 10(-6) M but was able to inhibit VIP-induced cAMP stimulation (K(b) = 79 nM). The K(i) values of [Tyr(9),Dip(18)]VIP(6-23) using the rat VPAC(2) and PAC(1) receptors were 3,000 nM and >10,000 nM, respectively. Thus, [Tyr(9),Dip(18)]VIP(6-23) is a selective VPAC(1) receptor antagonist. The C-terminally extended form, [Tyr(9),Dip(18)]VIP(6-28), displays improved antagonistic properties having a K(i) and K(b) values of 18 nM and 16 nM, respectively. On the contrary, the fully extended form, [Tyr(9),Dip(18)]VIP(1-28), was a potent agonist with improved binding affinity (K(i) = 0.11 nM) and ability to stimulate cAMP (EC(50) = 0.23 nM) compared with VIP (K(i) = 1.7 nM, EC(50) = 1.12 nM). Furthermore, the specificity of this agonist to the VPAC(1) receptor was high, the K(i) values for the VPAC(2) and PAC(1) receptors were 53 nM and 3,100 nM, respectively. Seven other analogs with the [Tyr(9),Dip(18)] replacement combined with previously published VIP modifications have been synthesized and described in this work.     

The synthesis of valperinol and various 3-aminomethyl derivatives of 2,9-dioxatricyclo[4,3,1,0(3,7)]decane from didrovaltrate

3-Aminomethyl derivatives of 2,9-dioxatricyclo [4,3,1,0(3,7)]decane, can be synthesized via an amination, starting from (1R, 3S, 4S, 6R, 7S, 8R, 10R)-3-iodomethyl-4-acetoxy-8-methoxy-10-methyl-2, 9-dioxatricyclo [4,3,1,0(3,7)]decane or (1R, 3S, 4S, 6R, 7S, 8R)-3-iodomethyl-4-acetoxy-8-methoxy-10-methylen-2,9- dioxatricyclo [4,3,1,0(3,7)]decane, which can be prepared from didrovaltrate.     

Synthesis and antitumor activity of 6-trifluoromethylcyclophosphamide and related compounds.

In an attempt to increase the combined toxicity of the metabolic end-products [acrolein (4) and phosphoramide mustard (3)] from cyclophosphamide (1), the analog 2-[bis(2-chloroethyl)amino]tetrahydro-6-trifluoromethyl-2H-1,3,2-oxazaphosphorine 2-oxide (2, 6-trifluoromethylcyclophosphamide) was synthesized and its metabolism and antitumor activity studied. Following metabolism of 2 by rat liver microsomes the predicted formation of 4,4,4-trifluorocrotonaldehyde (5) was confirmed by isolation and identification, by mass spectrometry, of its dinitrophenylhydrazone. The therapeutic indices (LD50-/ID90) for 2 against the ADJ/PC6 mouse tumor and the Walker 256 tumor in the rat were 28.6 and 7.7, respectively, and were lower than the corresponding values for 1 (91.8 and 33.2, respectively) although the toxicities toward Walker cells in a bioassay system of 1 and 2 following microsomal metabolism were similar. In order to study the toxicities of 4 and 5 released under drug metabolizing conditions independently of the production of a toxic mustard the analogs 18 [2-(diethylamino)tetrahydro-2H-1,3,2-oxazaphosphorine 2-oxide] and 6 [2-(diethylamino)tetrahydro-6-trifluoromethyl-2H-1,3,2-oxazaphosphorine 2-oxide] were also synthesized. The release of 5 from 6 following metabolism was confirmed and shown by use of the bioassay system to be an event of similar toxicity to release of 4 from 18; in vivo, however, 6 (LD50 330 mg/kg) was more toxic to mice than 18 (LD50 greater than 500 mg/kg).