Synthesis and antitumor activity of podophyllotoxin derivatives / 中国中药杂志

According to drug design flattening principle and using podophyllotoxin or 4'-demethylepipodophyllotoxin and aldehydes as starting material,a series of podophyllotoxin derivatives containing an imine structure with low toxicity were highly effective synthesized. Nine target compounds were successfully synthesized,and their structures were confirmed by ~1H-NMR,HR-ESI-MS and melting point data analysis. Using etoposide as positive control drug,nine target compounds were screened for cytotoxicity against He La cells in vitro by MTT method. The antitumor activity screening results showed that compound 6 b,6 d,6 e,6 f,6 g,6 i exhibited higher inhibitory rate against He La cells than those of control drug VP-16. It provides some practical reference value for the further development on the structure modification of podophyllotoxin and study on anti-tumor activity.

Inhibition on proliferation of HeLa cells in vitro of nano sllicon equipped with 4'-demethylepi-podophyllotoxin / 药物评价研究

Objective To study the inhibitory effect on proliferation of Hela cells of podophyllotoxin,4'-demethylepi-podophyllotoxin and drug combination of different proportion of nano-sillca (SiO2) and 4'-demethylepi-podophyllotoxin in vitro,and discuss the mechanism.Methods Used ethyl silicate hydrolysis method to prepare 25 nm SiO2 sample,next carried 4'-demethylepi-podophyllotoxin after the surface modification,and measure cell campatibility by MTT method and Hoechst 33342.The inhibitory effect of podophyllotoxin,4'-demethylepi-podophyllotoxin and drug combination on proliferation of Hela cells was measured by MTT assay.Hoechst 33342 staining method was used to detect cell apoptosis.The effect ofdmg combination treatment on cell morphology was observed by inverted microscope.Western blotting technique was used to detected effect of 4'-demethylepi-podophyllotoxin and drug combination on expression of apoptosis related protein.Results Inhibitory effect onproliferation of Hela cells of 4'-demethylepi-podophyllotoxin is superior to podophyllotoxin,inhibitory effect of drug combination is superior to the single 4'-demethylepi-podophyllotoxin,the inhibition of drug combination with 0.125 μg/mL nano SiO2 and 6.25 μg/mL 4'-demethylepi-podophyllotoxin is the most obvious.MTT and Hoechst 33342 experimental results showed that the 25 nm SiO2 have good cell compatibility.Podophyllotoxin,4'-demethylepi-podophyllotoxin and drug combination can induce apoptosis.Western blotting results showed that 4'-demethylepi-podophyllotoxin and drug combination can up-regulate the ratio of Bax/Bcl-2 and the expression level of Caspase-3、P53 and P38.Conclusion In vitro experimental performance of drug combination is superior to single 4'-demethylepi-podophyllotoxin,it is may by effecting the expression of Bcl-2,Bax,Caspase-3,P53,and P38 and others apoptosis related protein to induce Hela cell apoptosis.

Enzymatic glycosylation of 4'-demethylepipodophyllotoxin / 中国中药杂志

The glycosides of 4'-demethylepipodophyllotoxin (DMEP) possess various pharmacological activities; however, the chemical synthesis of these glycosides faces challenges in regioselectivity, stereoselectivity, and the protection and de-protection of functional groups. In this work, a novel glycosyltransferase (GT) gene AbGT5 from Aloe barbadensis was successfully cloned, heterogeneously expressed and purified. Recombinant AbGT5 was able to catalyze the glycosylation of DMEP and the glycosylated product, which was separated from the preparative scale reaction, was characterized as DMEP 4'-O-β-D-glucoside via MS, 1H-NMR, 13C-NMR, HSQC and HMBC. According to the investigations of enzyme properties, AbGT5 show the highest activity around 20 ℃ in the buffer of pH 9.0, and it was independent of divalent metal ions. Under the optimum conditions, the conversion rate of DMEP can reach 80%. Above all, in this work the enzymatic glycosylation of DMEP was achieved with high efficiency by the novel GT AbGT5.

ANTITUMOR ACTIVITY OF 4-〔4"-(2", 2", 6", 6"-TETRAMETHYL-1"-PIPERIDINYOXY)AMINO〕-4'-DEMETHYLEPIPODOPHYLLOTOXIN / 中国药理学通报

The antiumor activity of a new podophyllotoxin spin-labeled derivative, 4 -C 4 "-( 2 ", 2", C", 6"-tetramethyl- 1 "-piperidinyoxy ) amino]-4'-demethylepipodophyllotoxin ( GP-7 ) was studied. It was found that the growth of transplanted mouse tumors S180, HePS and Lewis lung cancer was markedly inhibited by GP-7. At a dose of 7.5-20 mg/kg, the inhibition rates of it against Sl80, HePS and Lewis lung cancer were 36.0-58.4, 29.6-60.0, and 27.2-46.5 % respectively. The toxicity of GP-7 was low, as indicated by the LD50 value of 231.2 mg/kg which was 3.3 times higher than that of etoposide ( VP-16 ) . On the other hand, the effects of GP-7 on spleen index and thymus index of mice bearing S180 tumor were remarkably lower than that of VP-16. In vitro GP-7 exhibited marked inhibition effects against L1210 and SGC-7901 cells. After exposure of L1210 cells to GP-7 and VP-16 5 mg/L for 24 h, the. inhibition rates were 75.5 and 73.6 %. after exposure of SGC-7901 cells to GP-7 and VP-16 5 mg/L for 72 h, the inhibition rates were 81.4 and 84.2 %. The new podophyllotoxin derivative GP-7 was similar to its structure analogues, clinical drug VP-16, in antitumor activity, while the toxicity of it was much lower than that of VP-16.