Design,Synthesis And Biological Activity Of NO Donor Tetrahydroisoquinoline Derivatives

Tetrahydroisoquinoline ring,as a common chemical structure,has good biocompatibility.Its derivatives have many biological activities,such as anticancer,antidepressant,anti-inflammatory and so on.Natural products containing cinnamic acid structural fragments,such as chalcone,curcumin,chlorogenic acid,have better anticancer activity and are potential antitumor drugs.No is the second messenger in human body.It can be used as a cytotoxic effector to mediate tumor cell apoptosis and can also modify various signal transduction molecules to change cell function.The purpose of this project is to design and synthesize a new NO donor type antitumor compound,and obtain a high-efficiency and low toxicity antitumor precursor through activity screening.The results showed that 2a has good antiproliferative activity to A549 and Hep G2cells(GI₅₀values were 21.85?2.03?M and 16.62?1.51?M respectively).On this basis,we further synthesized the intermediates 2b,10a and 10b,which contain the same structure as 2a.By combining the NO donor group with the intermediates,we hope to obtain serious compounds with strong antitumor activity and realize the superposition of antitumor effect.In this paper,20 NO donor tetrahydroisoquinoline derivatives were synthesized from 1,2,3,4-tetrahydroisoquinoline and substituted cinnamic acid,N-Boc-6-hydroxy-3,4-dihydroisoquinoline and ethyl bromoacetate respectively in 5 to 6 steps.All the target compounds were confirmed by ESI-MS,¹H NMR and ¹³C NMR.MTT method was used to investigate the effect of the target compound on the proliferation of human lung cancer A549 and Hep G2 cells,compared with Gefitinib in randomized controlled study.The results showed that all the targets had good inhibitory activity on A549 and Hep G2 cells(GI₅₀values were lower than 14?M).Among them,6b,6h,6j,13b,13g had a strong inhibitory activity on A549 cells and 6h,6j,13b,13e had a strong inhibitory on Hep G2 cells,with the GI₅₀value lower than 4?M;6d,13i had a relatively weak inhibitory activity on A549 cells and 6f,13a on Hep G2 cells,with the GI₅₀value higher than 10?M.Based on the evaluation results of antiproliferative activity,the target compounds 6j and 13i and intermediate 2a were selected.In Hep G2 cells,Griess method was used to detect the release of No.The results showed that at the same concentration level?1?M,3?M,10?M?,the NO release level of compound was 6j>13i>2a.When the concentration of the same compound was 1?M,3?M or 10?M,the NO release level of 6j,13i,2a increased with the increase of concentration.It is suggested that the anti-tumor cell proliferation activity of the compound is positively correlated with the NO release level,and the NO release level of the compound is dependent on the concentration.The effect of compound 6j on AKT and ERK1/2 protein phosphorylation was detected by Western blotting in Hep G2 cells.The results showed that compound 6j could significantly induce the expression of AKT and ERK1/2 in Hep G2 cells.Compared with the control group,when 6j concentration was 1?M,3?M and 9?M respectively,the levels of p-AKT and p-ERK1/2 in the cells decreased with the increase of concentration,showing a dose-dependent relationship.The results showed that the anti proliferation activity of the designed and synthesized target may be related to the high level of NO release in the cells and futher reduce the phosphorylation level of AKT,ERK1/2 and other related proteins in PI3K/AKT/m TOR and MEK/ERK signal pathways,as a result,the signal transmission can be blocked.