Chemical Constituents From Endophytic Fungus S15 Of Cephalotaxus Hainanensis Li

Endophytes are microorganisms such as fungi and bacteria (including actinomycete) that live inter-and/or intra-cellularly inside the healthy plant tissues causing asymptomatic infections for all or part of their life cycle. Endophytic fungi is an important part of the endophytc, they can produce numerous secondary metabolites with several structures, novel skeletons and varied and high bioactivities. They have been a very important source for searching new bioactivity natural product over decades. It’s reported that endophytic fungi have developed the biochemical ability to produce compounds similar or identical to those produced by their host plants。The ccphalotaxine esters of Cephalotaxus hainanensis Li have good effect in the treatment of leukemia.The plant is the national secondary protected plant on the brink of extinction,. That led us to start our investigation of the secondary metabolites produced by endophytic fungi of C. hainanensis Li.In our previously study, seventy-two strains of endophytic fungi were isolated from C. hainanensis. Endophytic fungi S15 and B15 were rich in the secondary metabolites by TLC analysis. Given the analysis results of the ITS sequence and the morphological characteristics of the strains, S15 and B15 were identified as Botryosphaeria rhodina and Guignardia camelliae respectively.Eight compounds were isolated from the broth of endophytic fungus S15 by column chromatography, and their structures were elucidated by physicochemical and spectral data (UV,IR, MS, 1D NMR, and 2D NMR) as 22E,24R-2a,3a,8a,16a-Tetrahydroxy-14a,15a-epoxyergosta-22,23-ene-21-carbolic acid(1)、11-Guaiene-10,13-diol(2)、11-Guaiene-3,10,13-triol(3)、7R*-10,11,12-Guaianetriol(4)、7S*-10,11,12-Guaianetriol(5), Cytochalasin D(6)、Zygosporin D(7)、Hymatoxin C(8). Among them, compounds 1-5 were new compounds.The content of compound 7 was analysed by HPLC method, which was 36.7mg/L in fermentation broth of endophytic fungus S15. The cytotoxic activities of all the compounds were measured by MTT method. Compound 2 exhibited cytotoxic activities against K562 cell lines. Compounds 7 and 8 exhibited cytotoxic activities against SMMC-7721 and SGC-7901 cell lines.