| In this dissertation, a series of plumbagin derivatives have been obtained through the structural modification of active constituent plumbagin from traditional Chinese medicine (TCM). Their antitumor activity, interaction with DNA, TopoⅠ, TopoⅡhave been investigated. Although plumbagin and its metal complexes exhibit good antitumor activity, the high toxicity and poor water solubility limit the bioavailability and the possibility of being as medicine. In order to reduce the toxicity and enhance water-solubility, the structural modifications of plumbagin have been undergone by introducing the functional group of enhancing water-solubility.Firstly, glycosylation is an effective strategy. Usually, carbohydrate drugs have the following characteristics:high hydrophilic can allow to be dissolved in water and exist in the outer aqueous phase of cell; or it can also connect with the biological macromolecules to forming glycoconjugates and permit play its biological function; or it can often be as carriers of biological information and so on. Considering a number of advantages of carbohydrate drugs, we chose glucose as a functional group to improve the water-solubility and reduce toxicity of plumbagin. Thirteen derivatives of glucose-plumbagin (5n,6n,7n, Scheme 1) have been synthesized, and their structures have been determined by elemental analysis, IR, mass spectrometry and nuclear magnetic resonance spectrometry. Using MTT methods, the in vitro antitumour activity of glucose-plumbagin compounds against eleven cell lines have been assayed. The results show that:at the concentration of 20μg/mL, the plumbagin-derivatives of 6n and 7n exhibited high inhibition rate on two tumour cell lines, hepatocellular carcinoma Bel-7404 and gastric cancer 7901, the compounds of 6n even more than 80%. Because of the low concentration of compounds of 5n, only 10μg/mL, the inhibition rate is relatively low, but it is accordance with literatures’values. Since DNA is considered as a crucial molecular target in tumor cells for anticancer drug, the interaction mode between these compounds and DNA has been studied by UV-vis absorption spectroscopy, EB competitive bonding experiments, circular dichroism absorption spectroscopy and viscosity titration analysis. Because of the poor planar configuration of plumbagin derivatives, the main interaction mode between these compounds and DNA is not classical intercalation, but groove binding as main mode, at the same time non-classical intercalation and weak electrostatic interaction may also exist. The binding mode to DNA was further examined by a gel mobility. The results agree with the spectral analysis results. Compounds 6n and 7n can inhibit the activity of TopoⅠof unwinding to pBR322 plasmid DNA, some derivatives of glucose-plumbagin can inhibit the activity of TopoⅡof unwinding to pBR322 plasmid DNA in lower concentration.Scheme 1.A series of glucose-plumbagin derivatives.Secondly, in order to enhance water-solubility of plumbagin derivatives, we chose glycerol and ethylene glycol as another functional group to combine plumbagin. Although the glycerol itself does not have antitumor activity, it has a wide range of applications in medicine. Currently, there are many studies show that glycerol can maintain the level of blood glucose and insulin, it can even replace certain high-calorie carbohydrates. Therefore we selected glycerol as functional group, to synthesize a series of plambagin-glycerol compounds (8n, Scheme 2).. Ethylene glycol has high water-solubility, and its polymer is a kind of phase transfer catalyst and can also be used in cell fusion, so it has been chosen to synthesize a series of plambagin-ethylene glycol (9n, Scheme 2). The structures of compounds 8n and 9n were identified by elemental analysis, IR, mass spectrometry and nuclear magnetic resonance spectrometry. Using MTT methods, the in vitro antitumour activity of these compounds against eight tumour cell lines had been estimated. The results indicate that these compounds, at the concentration of 20μg/mL show the activity against cervical cancer cells Hela, the inhibition rate up to 40%, towards gastric cancer 7901, the inhibition rate of compounds 8n is about 40%, of compound 92 is 57%, on breast cancer MCF-7, its rate exceeded 40%, on human liver cancer cell SMMC-7721, the rate of compound 93 is 64%. To compare the toxicity of these compounds to human normal cell, two human normal cell lines:human embryonic kidney 293 cells and human Chang liver cells, have been screened. The results show that these compounds exhibit higher toxicity to normal kidney 293 cells (more than 40%) than to chang liver cells (less than 40%). The main interaction mode between these compounds and DNA had been investigated by UV-vis absorption spectroscopy, EB competitive bonding experiments, circular dichroism absorption spectroscopy and viscosity titration analysis. The results show that these compounds interact with DNA in a grooving binding mode like plumbagin-carbohydrate derivatives. The binding mode to DNA has been further examined by a gel mobility. Topoisomerases are specific targets for a number of anticancer agents. Using agarose gel electrophoresis methods, the inhibition of some compounds on TopoⅠand TopoⅡhave been studied. The results show that compounds 8n and 9n can not inhibit the activity of TopoⅠof unwinding to pBR322 plasmid DNA; but most of them exhibit inhibition on TopoⅡat different concentrations, except compound 93.Scheme 2. A series of plumbagin-glycerol and ethylene glycol derivatives.In this dissertation, juglone with antibacterial and antitumour activity has been selected as ligand to chelate a series of metal ions with potential pharmacological activity, to results in the bifunctional metal-based compounds with synergistic effects. In this study, ten kinds of metal ions were involved, including CuⅡ, CoⅡ, NiⅡ, ZnⅡ, MnⅡ, CaⅡ, MgⅡ, PdⅡ, KⅠ, NaⅠ. The structures of these compounds were identified by elemental analysis, IR, UV-visible spectroscopy and mass spectrometry. In which, CuⅡ, CoⅡ, NiⅡ, ZnⅡare six coordinated to four O atoms from two juglone molecules and two O atoms from water molecules, forming six-coordinated complexes, MnⅡ, CaⅡwere coordinated to two O atoms from only one juglone molecule. In addition, KⅠ, NaⅠcompounds exist in ionic compounds. Using MTT methods, the in vitro antitumour activity of these compounds against eight tumour cell lines has been evaluated. The results indicate that these transitional metal complexes at the concentration of 20μg/mL show higher activity against on ovarian cancer SK-OV-3, gastric cancer 7901, breast cancer MCF-7, human renal clear cell adenocarcinoma 786-o, human colon cancer SW480, human liver cancer cell SMMC-7721 than juglone itself does, the inhibition rate of Cu complex towards gastric cancer 7901 is up to 77%, and toward ovarian cancer SK-OV-3 is more than 70%, while other metal complexes have the similar cytotoxicities to juglone. As comparison, two kinds of human normal cell lines was screened, human embryonic kidney 293 cells and human Chang liver cells, the results indicate that transitional metal complexes have high toxicity towards human Chang liver cells, up to 60%, but have low toxicity to human embryonic kidney 293, less than 30%. Through UV-visible absorption spectroscopy, EB competitive bonding experiments, circular dichroism absorption spectroscopy and viscosity titration analysis, the interaction mode between the juglone and its metal complexes with ct-DNA has been investigated. The spectroscopic analysis results indicate that juglone and its ionic compounds interact with ct-DNA in intercalation binding mode due to its good planarity, and other metal-based compounds adopted an partly intercalation mode interacting with ct-DNA. Of which, CuⅡ, CoⅡ, NiⅡ, ZnⅡcomplexes exibit higher intercalating ability than free juglone does, while KⅠ, NaⅠionic compounds exibit weaker intercalating abilities, The results are in adcordance with the in vitro screening data for antitumor activities. |
PDF Full Text Request