Isolation and mechanism study of cell cycle inhibitors from microbial metabolites.

我们一直在筛选土壤放线菌和真菌的微生物代谢产物，以获得新的细胞周期抑制剂。采用cdc 2激酶温度敏感性突变株tsFT 210细胞，通过流式细胞仪进行细胞周期分析。在筛选过程中，从长崎县分离的弯孢菌97-F166的发酵液中发现了一种新的细胞周期抑制剂，命名为弯孢酚。通过连续柱色谱法纯化弯孢酚，并获得无色针状晶体。经高分辨FAB质谱测定，其分子量为266，分子式为C_<15>H_<22>O_4。通过对其1D和2D NMR谱的详细分析，确定了其结构。Curvularol在100 μg/ml浓度下表现出较弱的体外抗菌活性，但在50 ~ 500 ng/ml浓度范围内表现出较强的细胞毒性。研究了Curvularol对细胞大分子合成的影响，认为Curvularol的主要作用靶点是蛋白质合成。在50 ng/ml时，它可将多种细胞系的细胞周期进程阻滞在G1期，包括tsFT 210、src^<ts>-NRK。

We have been screening microbial metabolites of soil actinomycetes and fungi to obtain new cell cycle inhibitors. The cell cycle analysis was carried out by flow cytometry using tsFT210 cell, a temperature-sensitive mutant cell line of cdc2 kinase. During this screening, a new cell cycle inhibitor named curvularol was discovered from the fermentation broth of a fungus, Curvularia sp. 97-F166, isolated in Nagasaki Prefecture. Curvularol was purified by a successive column chromatography and obtained as a colorless needle crystal. Its molecular weight and molecular formula were determined to be 266 and C_<15>H_<22>O_4, respectively, according to high-resolution FAB mass spectrometry. The structure of curvularol was elucidated by the detailed analyses of its 1D and 2D NMR spectra. It is a new sesquiterpen structurally related to trichotecenes to some extent.Curvularol showed a weak antimicrobial activity at the concentration of 100 μg/ml, but showed a strong cytotoxicity at the concentration range of 50〜500 ng/ml, in vitro. The effect of curvularol against the cellular macromolecular synthesis was examined, and the primary target of curvularol was suggested to be protein synthesis. It blocked the cell cycle progression at G1 phase of various cell lines including, tsFT210, src^<ts>-NRK at 50 ng/ml.