Three new methylated Δ8-pregnene steroids, stemphylisteroids A-C (1-3) were isolated from the medicinal plant Polyalthia laui-derived fungus Stemphylium sp. AZGP4-2. Their structures were elucidated by the detailed analysis of comprehensive spectroscopic data. The absolute configuration of 1 was determined by X-ray crystallographic analysis. Compound 1 show antibacterial activity against Escherichia coli with the MIC value of 6.25 μg/mL, and 2 exhibited a broad spectrum of antibacterial activities against six pathogenic bacteria with the MIC values ranging from 12.5 to 50 μg/mL. The discovery of three methylated Δ8-pregnene steroids 1-3 are a further addition to diverse and complex array of methylated steroids.

中文翻译：

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三种新的甲基化的Δ8-孕烯类固醇，它们来自Polyalthia laui衍生的真菌Stemphylium sp。AZGP4-2。

从药用植物Polyalthia laui衍生的真菌Stemphylium sp。中分离出了三种新的甲基化的Δ8-孕烯类固醇，即干叶类固醇AC（1-3）。AZGP4-2。通过对综合光谱数据的详细分析，阐明了它们的结构。通过X射线晶体学分析确定1的绝对构型。化合物1显示出对大肠杆菌的抗菌活性，MIC值为6.25μg/ mL，化合物2显示出对六种病原菌的广谱抗菌活性，MIC值为12.5至50μg/ mL。三种甲基化的Δ8-孕烯类固醇1-3的发现进一步丰富了甲基化类固醇的多样性和复杂性。