Biotransformation Of Steroidal Dioximes By Mucor Silvaticus And Antitumor Activity

The steroidal oximes have drawn significant attentions because of their biological functions such as antibacterial activity,antitumor activity and antiviral activity.In this thesis,steroidal oximes were underwent biotransformation to generate new oxime compounds which were investigated bioactivities via in vitro antitumor experiments so as to obtain effective antitumor compounds.These compounds are valuable for further research and development of new anticancer drugs.The investigations were carried out by transformation of steroidal dioximes which were synthesized by chemical method with Mucor silvaticus.The products of biotransformation were separated by silicagel column chromatography and were assigned structures by IR,ESI-MS,2D NMR(¹H NMR,¹³C NMR,DEPT,HMBC,HSQC,¹H-¹H COSY)spectrometries.The antitumor activities of 4-ene-3-one steroids,steroidal dioximes and biotransformation products were determined on the HeLa and RD cell lines by MTT assay.The steroidal dioximes were transformed by Mucor silvaticus,with the hydroxylation and hydrolysis of hydroxyimino group.Androst-4-ene-3,17-dioxime（4）were subjected to 6α-hydroxylation,7α-hydroxylation,along with hydrolysis of 3-hydroxyimino group,to produce7α-hydroxy-17-hydroxyimino-androst-4-ene-3-one（7）and 6α-hydroxy-androst-4-ene-3,17-di oxime（8）.The 17α-hydroxy-pregnen-4-ene-3,20-dioxime（5）were hydroxylated and hydrolyzied,to give 11α,17α-dihydroxy-20-hydroxyimino-pregnen-4-ene-3-one（9）,7α,17α-dihy droxy-20-hydroxyimino-pregnen-4-ene-3-one（10）and 7α,17α-dihydroxy-pregnen-4-ene-3-one（11）.The pregnen-4-ene-3,20-dioxime（6）was converted into 7α-hydroxy-20-hydroxyimino-pregnen-4-ene-3-one（12）and 7α-hydroxy-3-hydroxyimino-pregnen-4-ene-20-one（13）.From the structures property,the hydrolysis of 3-hydroxyimino group was more easily than 17 and/or20-hydroxyimino for the effect of 4-ene-conjugated structure.The results of MTT assay indicated that the steroids displayed time-and dose-dependent inhibitive effect on HeLa and RD cells.The compound 6 showed the highest cytotoxicity against the two cell lines,and the IC₅₀were 29.1μg/mL and 6.7μg/mL,respectively.The compound 13in biotransformation products had the hightest inhibition for HeLa cells,the IC₅₀ was 38.5μg/mL.The compound 12 showed the strongest inhibited effect on RD cells,the IC₅₀ was 13.4 μg/mL.