Löber G, Hoffmann H
Central Institute of Microbiology and Experimental Therapy, Academy of Sciences of the G.D.R., Jena.
Biophys Chem. 1990 Apr;35(2-3):287-300. doi: 10.1016/0301-4622(90)80016-z.
Ambazone (1,4-benzoquinone guanylhydrazone thiosemicarbazone) was found to be active against various transplantable tumors in mice as well as rats. When administered orally for 4-9 days, the effective therapeutic dose ranged between 60 and 125 mg/kg. The antineoplastic effect of ambazone appeared to be mediated, at least in part, by the immune system. In order to characterize the drug, biophysical and biophysicochemical studies were carried out using thin-layer chromatography, absorption spectroscopy and polarographic measurements. The distribution of ambazone in an n-octanol/water system indicated low hydrophobicity, thereby excluding the possibility of a preferential contribution from hydrophobic forces to the mode of action of ambazone. Ambazone undergoes three protonation reactions with pK values at 10.69 (equilibrium between the negatively charged and neutral forms), 7.39 (equilibrium between the neutral and singly positively charged form) and 6.22 (equilibrium between the singly and doubly positively charge form). Interaction of the drug with model membrane system was monitored by spectrophotometric and fluorescence measurements. Using the fluorescence label 1-anilino-8-naphthalenesulfonic acid (ANS) as a probe pointed to the interaction of ambazone with the inner area of the phospholipid bilayer matrix of liposomes as being nonspecific. Ambazone induces an overall increase in the cellular cAMP content of leukemia cells and macrophages. So far, membrane interaction has provided a molecular basis for both immunological and antineoplastic activities of the drug. By performing DNA melting experiments, it was shown that neutral or singly positively charged ambazone species stabilize the secondary structure of DNA, while the doubly positively charged form binds more strongly and destabilizes the DNA. After oral administration to rats and mice, ambazone was found to be incompletely absorbed from the gastrointestinal tract, to an extent of about 35-50%. Absorbed ambazone binds only weakly to plasma proteins, whereas its binding to red blood cells is relatively strong. The mutagenic potential of ambazone shown in bacterial systems and human lymphocytes corresponds to its relatively weak interaction with DNA. The toxic action of ambazone on the intestine is believed to be due to inhibition by the drug of bacterial DNA, RNA and protein syntheses. It is assumed that the reported affinity of ambazone for different cellular targets, i.e., membranes, nucleic acids and proteins, contributes to the overall antibacterial effect. The weak antiviral activity of ambazone in the Sendai virus/chicken embryo fibroblast system is probably the result of the interaction with Sendai virus NH glycoprotein.
氨巴腙（1,4-苯醌胍基腙硫代半卡巴腙）被发现对小鼠和大鼠的多种可移植肿瘤具有活性。口服给药4 - 9天，有效治疗剂量范围为60至125毫克/千克。氨巴腙的抗肿瘤作用似乎至少部分是由免疫系统介导的。为了表征该药物，使用薄层色谱、吸收光谱和极谱测量进行了生物物理和生物物理化学研究。氨巴腙在正辛醇/水体系中的分布表明其疏水性较低，因此排除了疏水力对氨巴腙作用方式有优先贡献的可能性。氨巴腙经历三次质子化反应，其pK值分别为10.69（带负电荷和中性形式之间的平衡）、7.39（中性和单正电荷形式之间的平衡）和6.22（单正电荷和双正电荷形式之间的平衡）。通过分光光度法和荧光测量监测该药物与模型膜系统的相互作用。使用荧光标记物1-苯胺基-8-萘磺酸（ANS）作为探针表明，氨巴腙与脂质体磷脂双层基质的内部区域的相互作用是非特异性的。氨巴腙可使白血病细胞和巨噬细胞的细胞内cAMP含量总体增加。到目前为止，膜相互作用为该药物的免疫和抗肿瘤活性提供了分子基础。通过进行DNA解链实验表明，中性或单正电荷的氨巴腙物种可稳定DNA的二级结构，而双正电荷形式结合更强并使DNA不稳定。给大鼠和小鼠口服给药后，发现氨巴腙从胃肠道的吸收不完全，吸收程度约为35 - 50%。吸收的氨巴腙与血浆蛋白的结合较弱，而其与红细胞的结合相对较强。氨巴腙在细菌系统和人淋巴细胞中显示出的诱变潜力与其与DNA相对较弱的相互作用相对应。氨巴腙对肠道的毒性作用被认为是由于该药物抑制细菌的DNA、RNA和蛋白质合成。据推测，所报道的氨巴腙对不同细胞靶点（即膜、核酸和蛋白质）的亲和力有助于其整体抗菌作用。氨巴腙在仙台病毒/鸡胚成纤维细胞系统中的弱抗病毒活性可能是其与仙台病毒NH糖蛋白相互作用的结果。
