Design, Synthesis And Mechanism Of In Vitro Anti-tumor, Anti-oxidation Action Study Of Novel Chalcones Des-C, FMC Analogous

Looking from natural products and development of new drugs or lead compounds isan effective approach to drug discovery. Chalcone compounds are widely distributed inplant flowers, leaves, barks and roots. Because chalcone skeleton is flexible, it can becombined with a variety of receptors and has a wide range of physiological activity, suchas anticancer, antioxidant, antibacterial, antimalarial and anti-HIV. So chalcone is a kindof important natural product which is valuable for research.In this paper, two natural products, new skeleton chalcone Desmosdumotin C (Des-C)isolated from roots of Desmos dumosus and FMC isolated from Cleistocalyx operculatus,were studied as lead compounds. The research contents are divided into two parts:1、 synthesis, design and antitumor activity of Des-C derivatives:(1) In this paper, on the basis of previous studies, we analyzed the datas that havebeen reported on the Des-C analogous on the cytotoxicity of A549tumor cell lines.Thenconstructed a3D-QSAR model to Structure-Activity Relationships (SARs) analysis. TheCoMFA results showed that the steric increased on Ring A, B, the electropositivity of RingB helped to improve the cytotoxicity. In this study, we executed the Structure-Activity Relationships study on the analogous. We extended the alkyl chains of Ring A, drawedsteric and electron-withdrawing groups into Ring B. and lengthened the chain structure ofC. Finally, we obtained43analogous (including42unreported). The synthetic route wasoptimized, and the key steps were discussed.(2) The anti-tumor mechanism of Des-C compounds is still unclear. In thisstudy, we treated HL-60cell with8μg/mL analogous and detected the cell apoptosis byflow cytometry. The results showed that the inhibitory activity of most analogous werehigher or equal to the lead compound (Des-C): There were27analogous stronger thanDes-C, the inhibition rate of10analogous were>40%,7analogous were between20-40%. Preliminary study on the mechanism of apoptosis on compound TEP-11suggest:1) the compond initiated infatal signal transduction pathway of HeLa cells by inducing theexpression of Fas and FasL;2) the compond increased expression of Bax in HeLacells and the downregulated Bcl-2expression, and the ratio of Bcl-2/Bax was significantlydownregulated, thereby induced the apoptosis of Hela cells.(3) The result of SARs analysis showed that: long alkyl chain substituted RingA, sterically hindered substituent on Ring B and para substituted on Ring B have greatcontribution to improve the inhibitory activity, but too large or affect the conformation ofthe lead compound may result in decreased activity; The activity did not show obviousregularity on electrical effects; Heterocyclic substituted Ring B decreased activity; Itwas no help to enhance activity by extending the C chain or draw flexible groups into Cchain. Through this part of the study, we hope to provide a theoretical basis and datasupport for the follow-up research.2、Synthesis of FMC and its analogous and the studies on in vitro anti-tumor,anti-oxidation activities.Aconcise synthesis toward3’-formyl-4’,6’-dihydroxy-2’-methoxy-5’-methylchalcone (FMC) and it analogues was firstly developed. In general, starting fromcommercially available2,4,6-trihydroxyacetophenone, formylation at3’position underVilsmeier-Haack condition was followed by the introduction of methyl group at5’position. The key step of selective methylation at2’position was achieved by trimethylsilyldiazomethane (TMSCHN2). Then various substituted aromatic aldehydeswere condensed through Claisen-Schmidt reaction in the presence of potassiumhydroxide. FMC and four analogues were synthesized and evaluated against a panel ofhuman cancer cell lines. Evaluation of these analogues showed that the4-bromosubstituted analogue FMC-2exhibited improved antiproliferative activity (EC50of6kinds of cell lines at10.8±0.9-20.2±1.6μM), demonstrating a great potential for thefurther development of FMC and its analogues as a new class of anti-cancer agents.Further modifications on this compound series and investigations of their mechanism ofaction are undergoing.In order to fully investigate the relationship between the structure and antioxidantactivity, excepting four specific chalcone componds: TEP-11, FMC, TMMS and Des-D,five structurally representative flavonoids componds: Apigenin,Chrysin(polyhydroxy flavones), Kaempferol (hydroxyl flavonol), Isoquercitrin and TJHH wereselected. We analyzed the in vitro antioxidant activities of9flavonoid compounds bybuilding and optimizing five antioxidant modle, including DPPH radical scavengingassay, hydroxyl radical scavenging assay, superoxide radical scavenging assay, NOradical scavenging assay and antioxidant system of iron ions. Through the analysis ofSARs, the relationship between structure difference and antioxidant activitywere summarized, which provide data that support for the study on the antioxidantactivity of flavonoids in the future.It can be seen from the experimental results that Isoquercitrin and Kaempferolshowed the strongest antioxidant activity, Apigenin and TJHH followed and Chrysin wasthe weakest. The SARs showed that: C ring with3’ hydroxyl substituent, B ring withhydroxyl substituents, especially3’,4’ dihydroxyl substituted had the greatest contributionto the antioxidant capacity, in addition to, pro-dione structure had a certain improvingeffect on antioxidant effect. To chalcones, the antioxidant capacity of structure containingphenol hydroxyl group Des-D, FMC was significantly higher than that of A ringnon-aromatic ring structure TMMS, TEP-11. It suggested that phenolic hydroxyl groupwas essential for antioxidant effect of chalcones. The physiological antioxidant effect of TMMS and TEP-11may work through the indirect pathway.