Study On Cephalotaxus Hainanensis Li.alkaloids And Their Bioactivities

Objective In order to study the structure and their biological activities of alkaloids from Cephalotaxus hainanensis Li.Isolation and identification of new compounds,enriching the treasure house of the chemical constituents of the Cephalotaxus,and developing new active research directions for the chemical constituents of C.hainanensis Li.Methods The branches of C.hainanensis Li.were extracted by leaching with EtOH three times at 80?C,the EtOH solution was concerntrated by reducing pressure,and then,extracted with chloroform under acidic condition and under alkaline condition,then with EtOAc and n-BuOH under neutral conditions,successively.The chloroform fraction and obtained under alkaline condition and EtOAc fraction were separated by a series of methods（Sephadex LH-20,CC on silica gel,RP-C18 gel,PTLC and analytical HPLC）and by recrystallization to yield 31 pure compounds.Their structures were identified by the modern spectrial analysis technoques(IR,UV,EI-MS,ESI-MS,HR-ESI-MS,¹H NMR,¹³C NMR,DEPT,HSQC,¹H-¹H COSY,HMBC and so on).Partial monomer compounds were evaluated for their antimicrobial activities against human pathogen（Staphylococcus aureus,MRSA,Candida albicans and Escherichia coli）by the paper-disc method,and their cytotoxic activities against human cancer cell lines（K562,SGC-7901,BEL-7402,A549 and HeLa）by using MTT method andα-glucosidase inhibitory activities.Results A total of 31 monomeric compounds were isolated from C.hainanensis Li.Their structure were identified as:cephahainanine（1）,2,3-epi-2-hydroxytaxodine（2）,cephalotaxine（3）,cephalotaxione（4）,isocephalotaxinone（5）,（+）acetylcephalotaxine（6）,deoxyharringtonine（7）,（R）-fortunine（8）,（S）-fortunine（9）,cephalezomine G（10）,（2R,3S,4S,5S）-2-3-dihydroxycephalotaxane（11）,isomer of 3-epi-schellhammericine（12）,cephalezomine H（13）,isocephalotaxine（14）,taxodine（15）,epierythratine（16）,drupacine（17）,1,4（Pr^INH）₂-anthraquinone（18）,benzopyrazole（19）,drummondol（20）,2-ethyl-n-hexyl benzoate（21）,4-hydroxy-3-methoxyphenthyl alcohol（22）,coniferaldehyde（23）,4-hydroxybenzaldehyde（24）,3,4-dihydroxybenzaldehyde（25）,isovanillin（26）,vanillic acid（27）,ω-hydroxypropioguaiacone（28）,β-sitosterol（29）,stigmasterol（30）,bis（2-ethylhexyl）phthalate（31）.All tested compounds for antimicrobial activity did not exhibit significant bacteriostatic activity.The IC₅₀ of compounds 7 and 17for chronic myeloid leukemia cell K562 were 0.06 and 4.86μM;for human gastric cancer cell SGC-7901 was 0.04 and 26.56μM;for human hepatoma cell BEL-7402 was 0.05 and9.70μM;for human lung cancer cells A549 were 0.04 and 22.99μM;for human cervical cancer HeLa was 0.04 and 11.00μM,respectively.The inhibition rates of compounds 3,7,10,20 and 25 forα-glucosidase were 46.6%,50.8%,42.2%,46.7%,and 57.0%（control:acarbose）.Conclusions Alkaloids,steroids,sesquiterpenes,and derivative of benzene were isolated and identified from C.hainanensis Li.Among them,compound 1 and 2 were new alkaloids.Compounds 1,2,5 and 8³1 were 27 compounds isolated from the C.hainanensis Li for the first time.Bioactivity studies showed that compound 7 has a certain antibacterial effect on Escherichia coli;compounds 7 and 17 have different degrees of in vitro cytotoxic activity against chronic myeloid leukemia cell K562,human gastric cancer cell SGC-7901,human liver cancer cell BEL-7402,human lung cancer cell A549 and human cervical cancer cell line HeLa;compounds 3,7,10,20 and 25 inhibitory activities ofα-glucosidase were higher than those of the control,indicating that the alkaloids and other components with good biological activity were found in C.hainanensis Li.