中文摘要：

目的对海南粗榧内生真菌S26发酵液的化学成分进行研究。方法用多种柱色谱技术对化合物进行分离纯化，用波谱技术和理化性质鉴定化合物的结构，采用MTT法测定化合物的抗肿瘤活性。结果从海南粗榧内生真菌S26的发酵液中分离得到1个环二肽和1个脂肪酸，分别鉴定为（3R，12aS）-3-methyl-2，3，6，7，12，12a-hexahydro—pyrazino[1，2-6]13-carboline-1，4-dione（1）和棕榈酸（2）。结论化合物1是首次分到的天然产物，化合物2在体外对胃癌细胞SGC-7901具有一定的抑制活性。

英文摘要：

OBJECTIVE To study the chemical constituents from endophytic fungus S26 of Cephalotaxus hainanensis Li. METHODS The constituents were isolated and purified by column chromatography, and their structures were identified by physicochemical and spectral data. The cytotoxic activity was measured using MTT method. RESULTS A cyclic dipeptides, （3R, 12aS） -3-methy1-2, 3, 6, 7, 12, 12a-hexahydropyrazino[l, 2-b]13-carboline-1, 4-dione （ 1 ） , together with palmtic acid （2） were isolated fi＇om the broth of endophytic fungus S26. CONCLUSION Compound 1 was isolated as a new natural product for the first time. Compound 2 exhibited moderate cytotoxic activity against SGC-7901.