Seven rare oxylipins, siegesbeckins A-G (1-7) representing further bioactive constituents different from the general terpenyl compounds found in Siegesbeckia species, have been obtained from the aerial parts of Siegesbeckia glabrescens. These isolates were identified to be a series of methyl 4-methylpentanoates incorporating fatty acid moieties of different chain lengths, based on spectroscopic techniques, and their absolute configurations were determined via chemical degradation and comparison with a synthetic sample. With respect to bioactivity, antibacterial, anti-inflammatory and cytotoxic properties of selected compounds were evaluated. Compounds 1 and 5 showed moderate antibacterial activity against two Gram-positive bacteria with MIC values of 4.3 μg/mL, while 3 showed no pronounced activity in these assays.

中文翻译：

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潜在的抑菌作用是来自Siegesbeckia glabrescens的新脂蛋白。

七种稀有的脂蛋白，siegesbeckins AG（1-7）代表了与Siegesbeckia物种中发现的一般萜烯化合物不同的其他生物活性成分，已经从Siegesbeckia glabrescens的地上部分获得。基于光谱技术，这些分离物被鉴定为一系列结合了不同链长的脂肪酸部分的4-甲基戊酸甲酯，并且它们的绝对构型是通过化学降解和与合成样品的比较来确定的。关于生物活性，评估了所选化合物的抗菌，抗炎和细胞毒性。化合物1和5对两种革兰氏阳性细菌显示中等的抗菌活性，MIC值为4.3μg/ mL，而化合物3和3在这些测定中没有明显的活性。