Two new diketopiperazines, namely samsoniellain A (1) and samsoniellain B (2), together with two known compounds (3, 4) were isolated from Cordyceps fungus Samsoniella sp. XY4. The planar structures of 1 and 2 were determined by HRESIMS, 1D and 2D NMR spectroscopy. The absolute configurations of 1 and 2 were determined by comparison of quantum chemical TDDFT calculated and experimental ECD spectra. Results of antimicrobial activity indicated that compound 2 showed weak bacteriostatic activities against S. typhimurium χ 8956, H. influenza ATCC 10211, MRSA 2024 with the MIC values of 128, 256, and 256 μg ml⁻¹, respectively. This is the first report about secondary metabolites of Samsoniella sp.

从虫草菌Samsoniella sp. 中分离出两种新的二酮哌嗪类药物，即samsoniellain A ( 1 ) 和samsoniellain B ( 2 ) 以及两种已知化合物( 3 , 4 ) 。XY4。1和2的平面结构通过HRESIMS、1D和2D NMR光谱测定。1和2的绝对构型是通过比较量子化学 TDDFT 计算和实验 ECD 光谱来确定的。抗菌活性结果表明，化合物2对鼠伤寒沙门氏菌χ 8956、流感嗜血杆菌ATCC 10211、MRSA 2024表现出较弱的抑菌活性，MIC值分别为128、256和256 μg ml ^-1。这是关于Samsoniella sp . 次生代谢产物的第一份报告。