Synthesis Of Dunniones-related Derivatives,their Anticancer Activities And Apoptosis Inducing Mechanism

In order to obtain lead compound and direction for synthesis,some natural quinones were used to investigate their anticancer properties and dock with target protein.In anticancer studies,N9(?-dunnione)manifested inhibiting percentage of nearly 100%against all tested cancer cell lines(good anticancer activities and broad anticancer spectrum),however,N9 showed almost no apoptotic-activity or apoptotic-markers-cleaving in SMMC-7721(hepatoma).N11(naphtho-dunnione)owned high antagonistic activity against MCF-7(breast cancer),whose anticancer intensity was 18.3 times to that of cisplatin,further more,N11 have a significant late-stage-apoptosis and apoptotic-markers-cleaving in MCF-7.Meanwhile,a positive correlation between the number of hydroxyl groups or hydrophobic aryl moieties on quinones and anticancer activities was found,and this pharmacological results were also confirmed by docking analysis.Above results indicated that?-dunniones were good lead compounds,and modifying their furan ring with aromatic or fused aromatic-ring(with hydroxyl groups)may achieve potent anticancer activities and“apoptotic/cancer-related-enzyme pathway”mechanisms.Under basylous conditions,phenols substrates,including natural flavonoids,higenamine,resveratrol and caffeic acid,were used to react with2,3-dichloro-1,4-naphthoquinone through condensation reactions to pruduce fused benzo-dunnione analogs.The reacting products were isolated and purified to give 15 derivatives.Structure elucidation and structure characterization were performed by MS,IR and 1D/2D-NMR,in which single crystal structures of S4and S8 were determined.The mother nucleus structures of S1,S2,S3,S5,S6,S10,S11,S12,S13 and S14 were novel,besides,S4,S9 were new compounds.S1,S2,S3,S4,S5,S6,S11 and S13 were benzonaphthofuroquinones(S2,S3,S6 were fused compounds of flavonoids moiety condensed with bis-naphthoquinonemoieties);S7,S8andS9were benzoylnaphthindolizinediones;S10 and S14 were naphthoquinones substituted by phenoxy or ester separately;S12 was fused compound of naphthoquinone moiety condensed with benzene ring by dioxane-bridge.The method of combining base-catalyzing with O₂/H₂O exposing was firstly used to prepare benzoylnaphthindolizinediones(S7,S8,S9).At the mean time,a vital semi-intermediate(S15)being finding in the reacting process,the reaction mechanisms were uncovered firstly here as further referring to the references:dihydroavone(naringenin)isomerized into trans-chalcone.Acetophenone blocks,which were generated from trans-chalcone via retro-aldol-like decomposition after hydration and isomerization,reacted with dichlone-pyridine intermediate to build a benzoylnaphthindolizinedione skeleton(S7,S8,S9).Water or oxygen being not involved in the preparation processes,S1,S2,S3,S5,S6,S11,S12,S13,S14 were synthetized by common methods as reported.While,S4,S10 were prepared by the method of combining base-catalyzing with O₂/H₂O exposing,in which O₂/H₂O was necessary for the reactions.The second dichlone molecule was introduced to the B-ring merely by C-O condensation reaction to achieve bis-naphthoquinone-flavonoid fused compounds(S2,S3,S6);C-ring of flavonol moiety in S5 was cleaved by hydration,and then underwent isomerization and degradation to give S4.In the anticancer investigations,benzonaphthofuroquinones(S2,S3,S4,S5)exhibited potent cytotoxicity against some carcinoma cell lines and low toxicity to normal cell lines,which meaned these derivatives have good selectivities for cytotoxicity;while the replacement of the furan ring by pyrrole system in benzoylnaphthindolizinediones(S7,S8,S9)resulted in the loss of anticancer activity.It was suggested that benzofuranoquinone core is essential for the observed cytotoxicities,in which the formed furan ring was the key structure.The derivatives(S2,S3,S4,S5)with good anticancer activities were used to investigate their anticancer mechanisms against HL-60 and B16 by apoptosis test and Western Blotting analysis.The apoptosis,induced by these compounds,mainly occurred in the late stage.As to the apoptotic effect and apoptotic markers(Caspase 3/PARP)cleaving,S4 or S5 showed more potent than S3 or S2.The anticancer mechanisms of S4 or S5 against HL-60 mainly resulted from the apoptosis and caspase 3 pathway,while the anticancer mechanisms of S4 or S5 against melanoma(B16)based not mainly on apoptosis or caspase 3pathway but others.In docking analysis,S4,S5 were bound to amino acid residues of the receptor pocket(caspase 3,1nms)mainly by hydrogen bonds,while S2,S3mainly by hydrophobic interactions,further more,S2,S3 owned grooves that inosculated with“C-shape pocket”of receptor.S4,S5 owned far more advantage than those of S2 or S3 in apoptotic/csapase 3 pathway,so it is a better way to ehance anticancer specificity to get more hydrogen bonds than to get more hydrophobic interactions.S3,S4,S5 with good anticancer effects also showed far stronger antimicrobial activities than other compounds,which indicated that they owned“antitumor-antibiotic”property.