RGD环肽修饰的姜黄素/黄芩苷靶向共递送纳米脂质体的制备工艺优化及表征

目的 优化RGD环肽修饰的姜黄素（curcumin,Cur）/黄芩苷（baicalin,Bai）共递送靶向纳米脂质体（RGD-Cur/Bai-Lip）的制备工艺并进行表征评价。方法 采用乙醇注入法制备RGD-Cur/Bai-Lip,首先通过Plackett-Burman筛选实验确定超声时间、胆脂比、水合温度作为制备RGD-Cur/Bai-Lip的关键因素,然后采用Box-Behnken响应面法进行工艺优化,以姜黄素包封率、黄芩苷包封率、总载药量为考察指标,采用AHP-复相关系数法-拉开档次法进行多指标组合赋权以确定各指标权重系数并计算综合评分,从而确定RGD-Cur/Bai-Lip的最优处方及关键工艺参数。最后对其形态、粒径电位、稳定性、体外释放度及溶血性等进行表征评价。结果 优选得到的最佳工艺为胆脂比1：12,水合温度60℃,探头超声时间为10 min。RGD-Cur/Bai-Lip外观澄清透明,呈亮黄色,对光可视淡蓝色乳光,透射电子显微镜下观察形态圆整、分散均匀。平均粒径为（101.10±0.62）nm,多分散系数（PDI）为0.191 0±0.014 3,Zeta电位为（1.59±0.07）mV,姜黄素包封率为（94.28±4.51）%,黄芩苷包封率为（76.93±1.35）%,总载药量为（2.27±0.09）%。7 d内稳定性良好,无溶血性,并具有一定的缓释作用。结论 优化处方后制备的RGD-Cur/Bai-Lip包封率高,粒径分布均匀,7 d内较稳定,无溶血性,并具有一定的缓释作用,为RGD-Cur/Bai-Lip的后续抗肝纤维化体内外研究提供了制剂基础。     

栽培银柴胡化学成分的研究

从栽培银柴胡Stellaria dichotoma L.vat.lanceolata Bge.的根中分析鉴定了7个化合物,经理化常数测定,气相色谱及光谱分析鉴定为α-菠甾醇(α-spinasterol)(1),β-谷甾醇(β-sitosterol)(2),豆甾醇(stigmasterol)(3),豆甾-7-烯醇(stigmast-7-enol)(4),α-菠甾醇葡萄糖甙(α-spinasterol glucosido)(5),豆甾-7-烯醇葡萄糖甙(stigmast-7-enol glucoside)(6),及银柴胡环肽(stellaria cy(?)lapeptide)(7).     

Cyclopeptide RA-V inhibits angiogenesis by down-regulating ERK1/2 phosphorylation in HUVEC and HMEC-1 endothelial cells

BACKGROUND AND PURPOSE

Anti-angiogenic agents have recently become one of the major adjuvants for cancer therapy. A cyclopeptide, RA-V, has been shown to have anti-tumour activities. Its in vitro anti-angiogenic activities were evaluated in the present study, and the underlying mechanisms were also assessed.

EXPERIMENTAL APPROACH

Two endothelial cell lines, human umbilical vein endothelial cells (HUVEC) and human microvascular endothelial cells (HMEC-1), were used. The effects of RA-V on the proliferation, cell cycle phase distribution, migration, tube formation and adhesion were assessed. Western blots and real-time PCR were employed to examine the protein and mRNA expression of relevant molecules.

KEY RESULTS

RA-V inhibited HUVEC and HMEC-1 proliferation dose-dependently with IC₅₀ values of 1.42 and 4.0 nM respectively. RA-V inhibited migration and tube formation of endothelial cells as well as adhesion to extracellular matrix proteins. RA-V treatment down-regulated the protein and mRNA expression of matrix metalloproteinase-2. Regarding intracellular signal transduction, RA-V interfered with the activation of ERK1/2 in both cell lines. Furthermore, RA-V significantly decreased the phosphorylation of JNK in HUVEC whereas, in HMEC-1, p38 MAPK was decreased.

CONCLUSIONS AND IMPLICATIONS

RA-V exhibited anti-angiogenic activities in HUVEC and HMEC-1 cell lines with changes in function of these endothelial cells. The underlying mechanisms of action involved the ERK1/2 signalling pathway. However, RA-V may regulate different signalling pathways in different endothelial cells. These findings suggest that RA-V has the potential to be further developed as an anti-angiogenic agent.     

大叶茜草中环肽类成分的研究

目的:对大叶茜草Rubia schumanniana根茎中环肽类化合物进行分离和鉴定.方法:大叶茜草根茎的70％甲醇回流提取物经硅胶,RP-18,Sephadex LH-20和HPLC等色谱技术分离纯化,根据波谱数据鉴定化合物的结构.结果:分离得到9个环肽类化合物,分别鉴定为RA-Ⅶ(1),RA-Ⅴ(2),RA-Ⅻ (3),rubiyunnanin C (4),RA-Ⅹ(5),RY-Ⅱ(6),RA-Ⅰ(7),RA-ⅩⅢ(8),RA-ⅩⅢ-OMe(9).结论:9个环肽化合物均为首次从大叶茜草中分离得到.     

Identification and structural basis of the reaction catalyzed by CYP121, an essential cytochrome P450 in Mycobacterium tuberculosis

The gene encoding the cytochrome P450 CYP121 is essential for Mycobacterium tuberculosis. However, the CYP121 catalytic activity remains unknown. Here, we show that the cyclodipeptide cyclo(l-Tyr-l-Tyr) (cYY) binds to CYP121, and is efficiently converted into a single major product in a CYP121 activity assay containing spinach ferredoxin and ferredoxin reductase. NMR spectroscopy analysis of the reaction product shows that CYP121 catalyzes the formation of an intramolecular C-C bond between 2 tyrosyl carbon atoms of cYY resulting in a novel chemical entity. The X-ray structure of cYY-bound CYP121, solved at high resolution (1.4 Å), reveals one cYY molecule with full occupancy in the large active site cavity. One cYY tyrosyl approaches the heme and establishes a specific H-bonding network with Ser-237, Gln-385, Arg-386, and 3 water molecules, including the sixth iron ligand. These observations are consistent with low temperature EPR spectra of cYY-bound CYP121 showing a change in the heme environment with the persistence of the sixth heme iron ligand. As the carbon atoms involved in the final C-C coupling are located 5.4 Å apart according to the CYP121-cYY complex crystal structure, we propose that C-C coupling is concomitant with substrate tyrosyl movements. This study provides insight into the catalytic activity, mechanism, and biological function of CYP121. Also, it provides clues for rational design of putative CYP121 substrate-based antimycobacterial agents.     

Xylopyrine-C,a new cyclopeptide alkaloid from Zizyphus xylopyra

Xylopyrine-C, a new 14-membered ring cyclopeptide alkaloid, has been isolated from the root bark of Zizyphus xylopyra together with a known alkaloid scutianine-C, and their structures were established by chemical and spectral evidences.     

银柴胡化学成分的研究

银柴胡为石竹科植物披针叶叉歧繁缕(Stellaria dichotoma L.var.lancenlata Bge.)的干燥根。主产宁夏,具有清热凉血之功效。我们从银柴胡中分离得到九种化合物。其中银柴胡环肽A及B为两个首次发现的新化合物。银柴胡根用甲醇提取,回收甲醇后悬浮于水中,用乙醚及正丁醇萃取。乙醚和正丁醇提取物再分别上硅胶柱,用氯仿-甲醇洗脱得到九个化合物。经理化常数测定(与标准品对照)气相层析及光谱方法鉴定了七种已知成分,分别为α-菠甾醇(α-spinasterol)(1)、B-谷     

海洋放线菌Kocuria sp.次级代谢产物的研究

目的 研究海洋放线菌Kocuria sp.的次级代谢产物。方法 菌株摇瓶发酵,采用现代色谱学方法(硅胶柱色谱、Sephadex LH-20凝胶柱色谱、半制备HPLC),对发酵产物进行分离,利用现代波谱学技术对化合物进行结构鉴定。结果 从海洋放线菌Kocuria sp.发酵液的乙酸乙酯萃取部分分离得到16个单体化合物：环(L-苯丙氨酸-L-脯氨酸)2 (1)、环(L-色氨酸-L-脯氨酸) (2)、环(L-色氨酸-D-脯氨酸) (3)、环(L-苯丙氨酸-D-脯氨酸) (4)、环(L-羟脯氨酸-L-苯丙氨酸) (5)、环(D-羟脯氨酸-L-苯丙氨酸) (6)、环(L-羟脯氨酸-L-酪氨酸) (7)、环(L-异亮氨酸-D-脯氨酸) (8)、环(L-亮氨酸-D-脯氨酸) (9)、环(L-亮氨酸-L-脯氨酸) (10)、环(L-苯丙氨酸-L-酪氨酸) (11)、环(L-亮氨酸-D-酪氨酸) (12)、环(L-亮氨酸-L-苯丙氨酸) (13)、环(D-缬氨酸-L-苯丙氨酸) (14)、环(D-亮氨酸-甘氨酸) (15)、环(D-异亮氨酸-甘氨酸) (16)。结论 海洋放线菌Kocuria sp.可产生结构丰富多样的环肽类化合物,所有化合物均首次从Kocuria属放线菌中分离得到。     

枣属植物化学成分研究进展

枣属（Ziziphus）为鼠李科植物中具有较高经济价值的一个属,约有170余种。迄今为止,已报道从枣属植物中发现或分离得到的化合物达200余种,主要包括三萜类、生物碱类、黄酮类、核苷类及糖类等化学成分。其中三萜类成分主要包括游离型的五环三萜类和以达玛烷型四环三萜为主要苷元的三萜皂苷类;黄酮类成分除含有氧苷类成分外,尚含有碳苷类成分,糖多取代在C-6或C-8位;生物碱类成分可进一步分为环肽生物碱类和异喹啉生物碱类。本文对近年来枣属植物化学成分研究的新进展进行总结,以期为枣属植物资源的深入开发与综合利用提供参考。     

炮制对王不留行中王不留行环肽A,B,E含量的影响

目的:研究炮制对王不留行中王不留行环肽A,B,E含量的影响,探索王不留行的炮制机制。方法:建立高效液相色谱法(HPLC)同时测定王不留行中王不留行环肽A,B,E含量的方法,采用Acclaim~(TM)120 C_(18)色谱柱(4.6 mm×250 mm,5μm),流动相乙腈(A)-水(B)梯度洗脱(0~8 min,32%A;8~13 min,32%~60%A;13~20 min,60%~70%A),流速1 m L·min~(- 1),检测波长220 nm,柱温40℃,进样量10μL。分析炮制前后王不留行环肽A,B,E含量及溶出率的变化。结果:炮制前后,王不留行环肽A,B,E在王不留行中含量差异较小,炮制前分别为0.035%,0.009%,0.017%,炮制后分别为0.033%,0.009%,0.015%;但3个成分的水煎溶出率分别升高了13.2%,5.3%,17.4%。结论:炮制对王不留行环肽A,B,E含量的影响较小,但炮制后3个成分的水煎溶出率均有增加。