Synthesis Of New Tetrandrine Derivatives And Their Activities Study

Objective:Tetrandrine(Tet), a kind of alkaloid isolated from the Chinese herb Stephania Tetrandra S.Moore, has been reported to comprise various pharmacological effects. In recent years, the antitumor activity of tetrandrine has been greatly concerned. So the structure modification of Tet leading for the target compound, which is promising to get more active derivatives better than the parent compound. Protein tyrosine kinases(PTKs),as a kind of important material to control cell growth and differentiation, which are the key signal to start synthesis of DNA and cell proliferation in multicellular reaction. It is now a hot topic in researching for the antitumor drug by inhibiting the activity of PTKs. In this paper, Tet was reacted with bromine in acetic acid in the solution of trifluoroacetic acid to give the key intermediate 5-bromotetrandrine, which was then coupled to the boronic acid via a Suzuki coupling reaction to produce 21 new derivatives. The structures of all the synthesized derivatives were confirmed by melting test, TLC, NMR spectroscopy and ESI-MS.To evaluate the anticancer potency of these target compounds, the cytotoxic activity of the derivatives were screened against A549 and HL60 cancer cell lines. The inhibition activities of the all target compounds were investigated by CCK8 assay, then the compounds which had better inhibition activity were secondary screened by MTT assay.The inbibitory ratio of the target compounds against PTKs including c-Met、ALK、FGFR1、RET、EGFR、ErbB2、KDR were tested by ELISA.Methods:1. Tet was reacted with bromine in acetic acid in the solution of trifluoroacetic acid to give the key intermediate 5-bromotetrandrine, which was then coupled to the boronic acid via a Suzuki coupling reaction to produce 21 new derivatives. The structures of all thesynthesized derivatives were confirmed by melting test, TLC, NMR spectroscopy and ESI-MS.2. The in vitro antitumor activity of the derivatives were carried out by CCK8 and MTT assay against A549 and HL60 cancer cell lines. Tet was used as the positive control.3. The inbibitory ratio of the target compounds against PTKs including c-Met、ALK、FGFR1、RET、EGFR、ErbB2、KDR were tested by ELISA.Results:1. 21 derivatives were syntheiesed and it was proved that all the compounds were first synthesized based on our analysis and related literatures.2. The results showed that the derivatives 2、3、5-9、12-18 possessed high cells inhibition on the two cell lines. Most of the screened compounds had considerable inhibition ratio compared to the parent compounds against the HL60 cell lines. All the screened compounds displayed higher cells inhibition compared to Tet against A549 cell lines. The compounds possessed high cells inhibition ratio(>50%) were further screened by MTT assay. The results showed that the antitumor activity of the compounds 3、5、6、9、16 and 18 were stronger than the parent drug, and the derivatives 3、5、6、9 were found to be about twice than that of Tet on the HL60 cell lines particularly. To the A549 cell lines,all the screened compounds displayed better activity than Tet. The derivatives 6 and 13 were found to be about three times stronger than that of Tet on the HL60 cell lines, and similarly, the cytotoxic activity of the derivative 5 was twice stronger than the parent drug.It demonstrated that the activity of the screened compounds had been improved obviously.Then a preliminary structure-activity relationship(SAR) was studied. These study reminded us that the adding of the benzyloxyphenyl moiety might exhibit good selectivity and activity towards HL60 cells. Consistent with the literature reports, heterocyclic could might enhance the activity of antitumor drugs. The antitumor activity of compounds may be related to the chain length of alkoxy moeity when the boronic acids containing alkoxy group in para- position, and the shorter chain exhibit a better selectivity and activity against the A549 cells.3. The enzyme activity inhibition test showed that compound 6、16 and 17 displayedbetter inhibitory effect for FGFR1. Compound 6, not only had the better inhibitory potency against the two cell lines, but also had a certain inhibitory activity to FGFR1 kinase.Conclusion:In this paper, we prepared 21 new Tet derivatives and the structures of the derivatives were determined by extensive spectroscopic data. Compound 6, not only had the better inhibitory potency against the two cell lines, but also had a certain inhibitory activity to FGFR1 kinase, was build a solid foundation for the future study.