Synthesis,Structrual Characterization And Antitumor Activity Of Anthracene Benzothiazole Hydrazone Derivatives And Their Metal Complexes

Based on the unique anthracene hydrazone moiety of bisantrene,a clinically used antitumor drug of anthracycline derivative,two novel anthracene benzothiazole hydrazone derivatives as ligands and their six complexes of copper（Ⅱ）,platinum（Ⅱ）and palladium（Ⅱ）,which are potential pharmacologically active elements,were synthesized and characterized.All the compounds’structures were fully characterized by IR,ESI-MS,NMR and single crystal X-ray diffraction analysis.On the cellular level,the in vitro antitumor activities of the compounds were tested by MTT assay,towards six common human tumor cell lines as well as two human normal cell lines as comparison.On the molecular level,the interaction mechanisms of the compounds with DNA and Topoisomerase I were studied by agraose gel electrophoresis and fluorescence spectroscopy.These works provided precious research experiences,laying the foundation of developing novel antitumor complexes of anthracene hydrazone derivatives.Research contents included are as follows:The two synthesized ligands were L^a and L^b,while the six corresponding complexes were Cu-L^a,Pt-L^a,Pd-L^a,Cu-L^b,Pt-L^b and Pd-L^b,which were characterized by IR,ESI-MS,NMR,and single crystal X-ray diffraction analysis,and were examined on their stability in solution by UV-Vis absorption spectroscopy.On the cellular level,the anti-proliferative effect of the eight compounds have been tested by MTT assay,thereby obtaining the data of inhibition rates and IC₅₀ values by Bliss method.Tested tumor cell lines included T-24,A549,MGC-803,Hep-G2,He La229 and NCI-H460,with two normal human cell lines of HL-7702 and WI-38 as an index of drug toxicity.Results showed that ligand L^a had no anti-proliferative effect on selected tumor cell lines,whereas a relatively high and broad-spectrum antitumor activity was observed with ligand L^b,as a result of introducing a hydroxymethyl group to the C10 position of anthracene ring instead of an aldehyde group,which enhanced the ligand’s antitumor activity,suggesting a certain structure-activity relationship.Among the six complexes,it was the two copper（Ⅱ）complexes that dominated the first place with the best antitumor activities.To make it in detail,complex Cu-L^b bearing the best antitumor activity displayed selectivity to T-24 and Hep-G2 with IC₅₀ value of about 4μM.By contrast,complex Cu-L^a showed slightly lower but more broad-spectrum antitumor activities than Cu-L^b.However,as for the platinum and palladium complexes,their antitumor activities were unexpectedly weaker than those of copper complexes,although these complexes formed with ligand L^b showed higher antitumor activities compared with those formed with ligand L^a.From the above,it was concluded that the antitumor activity of a complex was attributed to the ligand and its central metal ion,whose combination mode and synergistic effect played a crucial role in antitumor activities,indicating an apparent structure-activity relationship.Besides,cell cycle arrest experiment via flow cytometry revealed that as for T-24 cell line,ligand L^b arrested its cell cycle in S phase while the two copper complexes in G2 phase;and that for Hep-G2 cell line,complex Cu-L^a arrested its cell cycle in G2 phase while Cu-L^b in G1 phase.On the molecular level,the eight compounds’antitumor mechanisms with DNA and Topo I were investigated by fluorescence spectroscopy and agarose gel electrophoresis.It was demonstrated that the compounds were primarily bound to DNA by intercalation,and that the intensities of complexes binding to DNA were generally stronger than those of ligands,which suggested that the anthracene ring was an ideal group that could intercalate DNA,and this action was enhanced by electrostatic interaction from the coordinated metal ions.In addition,all the compounds could inhibit the activity of Topo I effectively,which was consistent with the mechanism of the classical anthracycline antitumor drugs.To sum up,two novel anthracene benzothiazole hydrazone derivatives and their metal complexes were synthesized and structurally characterized.Cu-L^b,a compound with high antitumor activity and clear pharmacological target,was screened out via the test on antitumor activity at cellular level and study on the interaction between compound and DNA or Topo I at molecular level,whose structure may serve for the further research on developing novel antitumor drugs with higher potency but lower toxicity.Moreover,this thesis expanded the library of metal complexes of anthracene hydrazones,and provided scientific data and fundamental information for a more comprehensive further study on the mechanisms of such novel antitumor metal complexes that contained the moiety of anthracene hydrazone.