Direct electron transfer of hemoglobin on dihexadecyl hydrogen phosphate/single-wall carbon nanotubes film modified Au electrode and its interaction with taxol

Direct electrochemistry of hemoglobin (Hb) immobilized on the dihexadecyl hydrogen phosphate (DHP)/single-wall carbon nanotubes (SWNTs) film modified Au electrode is investigated. The immobilized Hb displays a couple of stable and well-defined redox peaks, whose formal potential (E ⁰) is −0.434 V (SCE) in a phosphate buffer solution of pH 7.0. The formal potential of the heme Fe(III)/Fe(II) couple shifts negatively linearly with increased pH with a slope of −42.3 mV/pH, denoting that one electron transfer accompanies single proton transportation. Both SWNTs and DHP can accelerate the electron transfer between Hb and the electrode. Using DHP/Hb/SWNTs-film-modified Au electrode, the interaction between Hb and taxol is investigated. The voltammetric response of Hb decreases with increasing concentration of taxol. The peak currents decreases proportionally to the taxol concentration at 1.4 × 10⁻⁵ to 1.3 × 10⁻⁴ M, the linear regression equation being Δi (A) = 2.9603 − 0.4225 c_taxol (M), with a correlation coefficient (r) 0.9985, and the detection limit 6.95 × 10⁻⁶ M (signal-to-noise ratio of three). Published in Russian in Elektrokhimiya, 2007, Vol. 43, No. 7, pp. 801–807. The text was submitted by the authors in English.     

用HPLC对植物细胞培养液中紫杉醇的定量分析

以RP-HPLC对细胞培养液中紫杉醇的含量进行定量分析研究,并比较了2种不同的定量方法--标准曲线法和绝对分析法.实验结果表明:绝对分析法与标准曲线法测定的紫杉醇的摩尔吸光系数及样品中紫杉醇质量浓度结果的偏差在1.0%左右,验证了绝对分析法的可靠性. HPLC具有良好的线性关系(r=0.9999),加标回收率为97.9%～102.0%,相对标准偏差为2.1%,最低检出限为26.0μg·L-1。     

利用生物技术生产紫杉醇研究进展

紫杉醇是红豆杉属植物中含有的一种二萜类拟生物碱复化合物,具有独物的抗癌作用机理。     

紫杉醇与褪黑素联合使用对HeLa细胞的生长影响研究

目的：研究紫杉醇与褪黑素联合应用对HeLa细胞的生长影响。方法：通过生长曲线、集落形成试验观察二者联合应用对HeLa的影响作用。结果：单独应用紫杉醇和褪黑素与二者联合应用其生长曲线、集落形成试验的结果无明显差别。结论：紫杉醇与褪黑素联合应用对HeLa细胞的生长影响与单独应用二者无明显差别。     

真菌诱导物对红豆杉细胞的影响

从红豆杉树皮、根皮中分离得到了十种真菌,由这些真菌制成的真菌诱导物加入到红豆杉细胞培养物中后,均能引起细胞发生过敏反应,细胞生长量下降,培养液ｐＨ值降低,但是各种真菌诱导物对紫杉醇合成的促进作用有很大的差别,最佳的情况为加入真菌诱导物后,紫杉醇的含量达到细胞干重的０．０７％．可为红豆杉细胞大规模培养提高紫杉醇的产量提供依据．     

Theoretical study on the reactive sites and intramolecular interactions in taxol and its four analogues

A density‐functional study of the paclitaxel (Taxol) molecule and its four analogues has been performed. The theory of Bader's atoms in molecules (AIM) was applied to examine the electronic structure of these molecules at their ground state. Topological analysis reveals that the esterification of hydroxyl group attached to the oxetane ring results in great change of conformation of the taxane ring, and thus is responsible for bioactivity of the oxetane oxygen atom. It was found that there exists some intramolecular interactions in the molecule, including normal hydrogen bonds (HBs) and double HBs. Visualization of the molecule shows that the central bodies (the four fused rings) of the molecules are wrapped by the intramolecular interactions. It is supposed that these intramolecular interactions lower the aqueous solubility and protect the flexible oxetane ring, which is regarded as the dominating bioactivity site of the drug, from being opened. Our results provide an extended and consistent set of data to gauge classical force fields in view of the atomistic investigations of the interaction of the bioactive molecules. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2009     

几种释放因素对紫杉醇合成与释放的影响

比较研究了几种释放因素对红豆杉细胞生长和紫杉醇合成与释放的影响,结果表明,在中国红豆杉细胞悬浮培养过程中,在细胞生长对数期（14d)加入φ＝5％二甲亚砜及0．2mol/L甘露醇,能显著提高紫杉醇的合成及释放,紫杉醇总产量达到16mg/L,在细胞生长在对数期（14d)加入0．04mol/L氯化钠时,紫杉醇总产量达到7．3mg/L,在细胞生长对数期（14d）加入2mg/L硫酸铈铵时,紫杉醇总产量达到24mg/L。     

南方红豆杉组织培养和紫杉醇含量测定

比较了从南方红豆杉的芽及幼茎诱导愈伤组织的情况,并对愈伤组织的增殖条件进行了研究,利用HPLC方法测定了愈伤组织合成紫杉醇的能力,结果表明以芽作为外植体在附加2．0mg/L 2,4-D 和0．5mg/L NAA的MS培养基上,产生愈伤组织的速度较快,诱导效果最好,第5天即有愈伤组织发生,且诱导率可达100％,附加0．5mg/L,2,4-D,1.0mg/L NAA和0．5mg/L KT的B5培养基较适合愈伤组织的增殖,生长率达7．74g/L,紫杉醇含量达干重的0．0098％。     

苏型-N-苯甲酰基-3-苯基异丝氨酸甲酯的合成

紫杉醇;苏型-N-苯甲酰基-3-苯基异丝氨酸甲酯的合成     

抗癌药物紫杉醇的制备、抗癌机理和应用前景

紫杉醇具有显著的抗癌活性和独特的作用机理,现主要用于治疗晚期乳腺癌和卵巢癌等。紫杉醇分子结构复杂,具有特殊的三环[6+8+6]碳架和桥头双键以及众多的含氧取代基,其全合成引起国内外许多有机化学家的兴趣。本文简述紫杉醇的制备、抗癌机理和不良反应。