雷公藤内酯醇的结构修饰

为降低雷公藤内酯醇的毒性,寻找高效低毒的抗炎免疫化合物,对雷公藤内酯醇(trip-tolide,1)的结构进行了修饰,合成了九个雷公藤内酯醇衍生物。初步活性测定显示雷公藤氯内酯(tri-pchlorolide,2)和雷公藤溴内酯醇(tripbromolide,3)的免疫抑制活性与雷公藤内酯醇近似,但毒性有所降低。其他化合物的活性大大低于雷公藤内酯醇。     

雷公藤叶中二萜化合物的研究

从雷公藤(Tripterygium wilfordii)叶中分离出九个二萜化合物,经物理常数测定、化学反应、以及波谱数据分析,分别鉴定为雷公藤内酯酮(triptonide,1)、雷公藤内酯醇(triptolide,2)、雷公藤内酯二醇(tripdiolide,3);雷醇内酯(triptolidenol,4)、16-羟基雷公藤内酯醇(16-hydroxytriptolide,5)、雷公藤氯内酯醇(tripehlorolide,6)、雷藤内酯三醇(triptriolide,7),以及新化合物雷公藤内酯二醇酮(tripdiotolnide,8)和13,14-环氧9,11,12-三羟雷公藤内酯(13,14-epoxide 9,11,12-trihydroxytriptolide,9)。新化合物的生物活性正在研究。     

雷公藤中的一种新活性成分一16-羟基雷公藤内酯醇

从雷公藤(Tripterygiurn wilfordii Hook f.)的叶、根及制剂“雷公藤多甙”中分离出一个新的三环氧二萜内酯化合物-16-羟基雷公藤内酯醇(L_2)。该化合物是一种白色簇状结晶,熔点232-233.5℃,分子式为C_20H_24O_7。根据光谱(UV,IR,MS,~1HNMR,~13CNMR,2d-NMR和Se-lective Long-range DEPT)数据分析,确定了其化学结构,并通过X-射线晶体分析确证了它的立体化学。15-C为“S”构型的手性碳。药理试验表明,16-羟基雷公藤内酯醇具有较强的抗炎、免疫抑制和雄性抗生育活性。另外,还分离到已知化合物雷公藤内酯醇,并通过2d-NMR等光谱分析归属了全部碳和质子的NMR光谱峰。     

HPLC-TOF/MS研究雷公藤甲素及雷公藤内酯酮体内代谢产物

目的 鉴定甘草干预后雷公藤甲素及雷公藤内酯酮在大鼠体内的代谢物,为其结构改造与新药研发提供参考.方法 采用高效液相色谱-飞行时间质谱(HPLC-TOF/MS)法研究甘草干预后雷公藤甲素及雷公藤内酯酮在大鼠尿液中的代谢物.结果 发现雷公藤甲素代谢物4个,分子量为376Da代谢物2个,390Da代谢物2个;雷公藤内酯酮代谢物5个,分子量为372Da代谢物1个,374Da代谢物1个,390Da代谢物3个.根据高分辨质谱精确分子量以及药物体内代谢规律鉴定为一羟基化雷公藤甲素(M1,M2,376Da),一羟基一羰基化雷公藤甲素(M3,M4,390Da);一羰基化雷公藤内酯酮(M5,372Da),一羟基化雷公藤内酯酮(M6,374Da),二羟基化雷公藤内酯酮(M7,M8,M9,390Da).结论 一羰基化雷公藤内酯酮(M5)及3个二羟基化雷公藤内酯酮(M7,M8,M9)代谢物为首次报道.     

异雷公藤内酯四醇的半合成研究（Ⅰ）

以雷公藤内酯酮为原料,经烯丙位烃基氧化、亲核酰化和还原反应,合成了异雷公藤内酯四醇,其结构经红外光谱、核磁共振光谱、质谱确证。     

肾靶向雷公藤内酯醇与2-氨基葡萄糖结合物的合成

目的 合成雷公藤内酯醇与2-氨基葡萄糖的结合物(TPG).方法 将雷公藤内酯醇与丁二酸酐反应生成雷公藤内酯醇丁二酸单酯,其游离羧基与2-脱氧-2-氨基-D-吡喃葡萄糖氨基乙苷1位上的氨基形成酰胺键,得到TPG前药,并鉴定其结构.结果 成功制备了TPG,其所含2-氨基葡萄糖具有肾靶向性,并改善了其水溶性.结论 该前药的合成路线可行性高,TPG具有肾靶向性,雷公藤内酯醇的水溶性得到了改善.     

雷公藤中的一种新活性成分——16—羟基雷公藤内酯醇

从雷公藤（Tripterygium wilfordii Hook f.）的叶、根及制剂“雷公藤多甙”中分离出一个新的三环氧二萜内酯化合物－－16－羟基雷公藤内酯醇（L2）。该化合物是一种白色簇状结晶，熔点232－233.5℃，分子式为C20H24O7。根据光谱（UV，IR，MS，^1HNMR,^13CNMR,2d-NMR和Se-lective Long-range DEPT）数据分析，确定了其化学结构，并通过x-射线晶体分析确证了它的立体化学。15－C为“S”构型的手性碳，药理试验表明，16－羟基雷公藤内酯醇具有较强的抗炎、免疫抑制和雄性抗生育活性。另外，还分离到已知化合物雷公藤内酯醇，并通过2d-NMR等光谱分析归属了全部碳和质子的NMR光谱峰。     

穿心莲内酯衍生物抗肿瘤、解热抗炎构效关系研究进展

目的对近年来穿心莲内酯衍生物抗肿瘤、解热抗炎的构效关系研究进展综述,为穿心莲内酯的进一步研究提供思路。方法对相应文献进行归纳、总结和综述。结果穿心莲内酯及其衍生物发挥抗肿瘤活性的必需基团是完整的α-亚烷基-γ-丁内酯,Δ12,13双键,Δ8,17双键或成环及C14羟基等活性基团;而α-亚烷基-γ-丁内酯环打开与否和抗炎无关,穿心莲内酯及其衍生物的双键位置决定其抗炎作用,具有环内双键的化合物抗炎作用强于具有环外双键的化合物。结论穿心莲内酯衍生物具有良好的开发前景,应加强其衍生物与构效关系的研究。     

雷公藤内酯醇对肺腺癌细胞系A549的体外抑制作用的研究

目的观察雷公藤内酯醇对肺腺癌细胞系A549体外生长特性的影响。方法分别采用MTT法、流式细胞仪、琼脂糖凝胶电泳以及荧光染色观察雷公藤内酯醇肺腺癌细胞系A549增殖、细胞周期以及凋亡的影响。结果14nmol.L-1～896nmol.L-1的雷公藤内酯醇均能抑制A549细胞的生长且生长抑制作用呈剂量以及时间依赖性。雷公藤内酯醇在低浓度(14nmol.L-1)条件下,能诱导A549细胞发生细胞周期阻滞,阻滞部位在S期;高浓度(55,112mol.L-1)的雷公藤内酯醇使A549阻滞在G2/M期,并诱导其发生凋亡。结论雷公藤内酯醇能抑制A549细胞的生长,使其阻滞在S期和G2/M期,并诱导其发生凋亡。     

雷公藤内酯醇的药理研究

目的：介绍近10年来雷公藤内酯醇药理学研究进展。方法：以国内外大量有代表性的论文为依据，进行分析、整理和归纳。结果：综述了雷公藤内酯醇的体内过程，抗肿瘤、抗炎及免疫抑制和抗雄性生育作用以及毒性作用。结论：雷公藤内酯醇不仅是一个药理活性较强的，而且还是一个毒性较大，具有较强的致突变作用的化学成分。     

喜树碱结构修饰与构效关系研究进展

喜树碱是从喜树提取物中分离出的能够抗细胞增殖的天然生物碱。由于其溶解性低、稳定性差和显著的不良反应限制了其临床应用,所以在过去的十余年里合成了许多喜树碱衍生物。通过引入极性基团、靶向剂或药效团拼合、前药等在喹啉环、5位和20位进行结构修饰,其中大多数与喜树碱相比显示出更强的效力,对不同的肿瘤细胞具有活性,其中许多对多药耐药肿瘤细胞具有活性。综述了近年来47个新的喜树碱衍生物的合成方法和生物活性,并总结了构效关系,发现在喹啉环和内酯环的羟基上修饰通常可以增强体外抗肿瘤活性,药物递送系统、计算机高通量筛选等新技术的应用为改善喜树碱的溶解性、稳定性,寻找活性较好的先导化合物拓展了新思路。     

Immunochemical characterization of the functional constituents of Tripterygium wilfordii contributing to its anti-inflammatory property

1. Tripterygium wilfordii (TW) contains bioactive compounds that possess immunosuppressive properties. These compounds are considered to be potential drugs in the treatment of acute graft rejections. However, their structure-activity relationships remain unknown. 2. The aim of the present study was to delineate the molecular moieties of triptolide that could account for its ability to inhibit inflammatory responses. In this context, purified TW active compounds (triptolide and triptonide) and synthetic triptolide derivatives were prepared to investigate the structure-activity relationships of triptolide. To this end, rat splenocytes were treated with increasing concentrations of the compounds and then allogenically stimulated using a mixed lymphocyte reaction to determine their antiproliferative activities. From the results, the IC50 value of each compound was calculated. 3. Modification of the beta-hydroxyl group at the C-14 position of the triptolide molecule significantly affected the immunosuppressive activity of T59, as demonstrated by a sevenfold increase of the IC50. Conversely, reduction of the gamma-butyrolactone group in T60 and T61 completely abrogated the antiproliferative effect. Alterations in the C-14 beta-hydroxyl and gamma-butyrolactone groups also resulted in reduced cytotoxicity. 4. The present findings demonstrate that the C-14 beta-hydroxyl and gamma-butyrolactone moieties of the triptolide molecule are crucial for its anti-inflammatory properties and cytotoxicity and are responsible for the compound's antiproliferative activity.     

Structure-activity relationship of quinolone antibacterial agents: the effects of C-2 substitution

Very little is known about the structure-activity relationship of quinolone antibacterials at the 2-position. Because of the loss of biological activity with 2-methyl and 2-hydroxyl substitution, modifications at C-2 were generally considered to be unfavourable. Quinolone derivatives having a ring between positions 1 and 2 were recently shown to have biological activity. The sulfur-bridged analogs such as the benzothiazolo[3,2-a]quinolone, KB-5246 and NAD-394 have been reported to be highly active in vitro. The authors have synthesized 2-methylthiociprofloxacin, 2-methylofloxacin, the 5-oxopyrrolo[1,2-a]quinoline and isothiazolonaphthyridine to assess the importance of the sulfur atom on biological activity as well as the effect of C-2 substituent on the spatial arrangements of N-1 or the 3-carboxylic group. It was found that the planarity between the 4-keto and 3-carboxylic acid groups of quinoline molecules is the most important criterion for biological activity. The syntheses of the above four compounds are also described.     

2-Heteroaryl 2-Substituted Phenylketone Derivatives and Their Inhibitory Activity on Platelet Aggregation

R 68070 and CV-4151 are two compounds possessing both thromboxane synthetase inhibitory activity and thromboxane receptor antagonist properties. 2-Heteroaryl 2-substituted phenylketone derivatives with a partial structural similarity to R 68070 and CV-4151, i.e. possessing a phenyl and a heteroaryl moiety, have been prepared and found to have antiplatelet activity. The compound 2-thienyl 2′-hydroxyphenyl ketone (4) was shown to completely inhibit platelet aggregation induced by arachidonic acid at a concentration of 5·0 μm . Structure-activity analysis indicated that the presence of a ketone group is an important requirement for this inhibitory activity. An o-hydroxyl substitution on the phenyl ring, and a 2-thienyl of heteroaryl ring might increase inhibitory activity.     

Structural and biological diversity of natural p-terphenyls

p-Terphenyls consisting of a C-18 tricyclic or polycyclic C-18 aromatic skeleton, have diverse structures because of the variation of the middle ring and the connections between the rings, and to the main skeleton. p-Terphenyls have recently been found to exhibit various biological activities such as cytotoxic, α-glucosidase inhibitory, antioxidant, and antimicrobial activity. In this review, we briefly summarized the structural varieties, biosyntheses, and bioactivities of natural p-terphenyl derivatives referring to the recent 10 years' publications.     

Effect of the derivatives of andrographolide on the morphology of <Emphasis Type="Italic">Bacillus subtilis</Emphasis>

Andrographis paniculata has been reported to have antiviral, antipyretic and anticancer activities. Andrographolide, an ent-labdane diterpene, is an active constituent in this plant. In this study, andrographolide (1) and its natural derivative 14-deoxy-11,12-didehydroandrographolide (2) and 5 other semisynthetic derivatives were tested for their activity against Grampositive and Gram-negative bacteria and Candida albicans. Only derivatives bearing a 14-acetyl group showed activity, and this activity was only against Gram-positive bacteria. 14-Acetylandrographolide showed the highest potency against Bacillus subtilis; the other 14-acetylandrographolides with additional substitution at the 3- and 19-hydroxyl groups showed lower activity against Gram-positive bacteria. The morphology of B. subtilis after being treated with 14-acetylandrographolide was investigated with TEM. This is the first report on 14-acetylandrographolide’s quantified antibacterial activity, and the crucial functional group of this ent-labdane that plays an important role in perturbing the morphogenesis of B. subtilis leading to cell death.     

Structural essentials of xenoestrogen dialkyl phthalates to bind to the estrogen receptors

Xenoestrogen dialkyl phthalates, C(6)H(4)(COOC(n)H(m))(2), lack the phenolic hydroxyl group that is an essential structural component of the steroid A ring of 17 beta-estradiol. In order to examine whether dialkyl phthalates imitate the steroid structure, we have synthesized a series of 4-hydroxyl derivatives of dialkyl phthalates. The compounds were examined for their ability to displace [(3)H]17 beta-estradiol from the recombinant human estrogen receptor, which was expressed on Sf9 cells using the vaculovirus expression system. Dialkyl 4-hydroxyl phthalates were found to exhibit several-fold higher binding affinities compared to phthalates without the 4-hydroxyl group. From the analyses of receptor binding modes of dialkyl phthalates with and without the 4-hydroxyl group, it was deduced that the phthalic benzene ring mimics the steroid A ring. A biphasic binding curve observed for dicyclohexyl phthalate was also depicted by its 4-hydroxyl derivative, but it increased binding affinity only at the high affinity binding site. These data suggest that the phthalate benzene moiety recognizes the core of the estrogen receptor binding site and the hydrophobic interaction of the dialkyl moiety substantiates the binding characteristics of the phthalates. The present data indicate that even chemicals with slight structural analogy and weak receptor affinity can perturb the endocrine system when administered in high concentrations.     

Synthesis and biological evaluation of novel benzyl-substituted flavones as free radical (DPPH) scavengers and α-glucosidase inhibitors

Pharmacologically motivated natural product investigations have yielded a large variety of structurally unique lead compounds with interesting biomedical properties, but the natural roles of these molecules often remain unknown. In the present investigation, a series of benzyl substituted-flavone derivatives have been synthesized from the lead compounds and were screened against 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging and α-glucosidase inhibitory properties. The resulting activity profiles of these flavone derivatives were compared for degree of similarity to the profile of 1–3. Most of the synthesized derivatives displayed potent activities when compared to the parent compounds. Maximum potencies for DPPH free radical scavenging activity were observed only in compounds containing the 4-hydroxyl substitution and 3-methoxyl group on the phenyl ring. While the 2- and 4-hydroxyl group substitutions on the phenyl ring seem to be crucial for the intestinal α-glucosidase inhibitory activity.     

Betulinic acid derivatives as anticancer agents: structure activity relationship

Betulinic acid, a pentacyclic triterpene, is widely distributed throughout the tropics. It possesses several biological properties such as anticancer, anti-inflammatory, antiviral, antiseptic, antimalarial, spermicidal, antimicrobial, antileshmanial, antihelmentic and antifeedent activities. However, betulinic acid was highly regarded for its anticancer and anti-HIV activities. Anticancer role of betulinic acid appeared by inducing apoptosis in cells irrespective of their p53 status. Due to high order safety in betulinic acid, a number of structural modifications carried out to improve its potency and efficacy. The C-1, C-2, C-3, C-4, C-20 and C-28 positions are the diversity centers in betulinic acid, and the derivatives resulted on various structural modifications at these positions screened for their anticancer activity. This review presents the structure activity relationship carried out on C-1, C-2, C-3, C-4, C-20, C-28, A-ring, D-ring and E-ring modified betulinic acid derivatives. We have compiled the most active betulinic acid derivatives along with their activity profile in each series. Structure activity relationship studies revealed that C-28 carboxylic acid was essential for the cytotoxicity. The halo substituent at C-2 position in betulinic acid enhanced the cytotoxicity. Though the relation of the cytotoxicity with the nature of substituents at C-3 position could not be generalized but the ester functionality appeared to be a better substituent for enhancing the cytotoxicity. An interesting observation is that the three rings skeleton (A, B and C rings) had played an important role in eliciting anticancer activity, which could be a new molecular skeleton to design new anticancer drugs.     

Synthesis and biological evaluation of novel benzyl-substituted flavones as free radical (DPPH) scavengers and α-glucosidase inhibitors

Pharmacologically motivated natural product investigations have yielded a large variety of structurally unique lead compounds with interesting biomedical properties, but the natural roles of these molecules often remain unknown. In the present investigation, a series of benzyl substituted-flavone derivatives have been synthesized from the lead compounds and were screened against 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging and α-glucosidase inhibitory properties. The resulting activity profiles of these flavone derivatives were compared for degree of similarity to the profile of 1-3. Most of the synthesized derivatives displayed potent activities when compared to the parent compounds. Maximum potencies for DPPH free radical scavenging activity were observed only in compounds containing the 4-hydroxyl substitution and 3-methoxyl group on the phenyl ring. While the 2- and 4-hydroxyl group substitutions on the phenyl ring seem to be crucial for the intestinal α-glucosidase inhibitory activity.