Department of Chemistry and Biochemistry, Jackson State University, Jackson, MS 39217, USA.
Exp Biol Med (Maywood). 2010 Dec;235(12):1472-8. doi: 10.1258/ebm.2010.010124. Epub 2010 Oct 20.
Vernonia amygdalina (VA) is widely used for medicinal and food purposes in tropical Africa. Many health benefits (antioxidant, antimicrobial, anticancer activities and more) of VA extracts have been reported. The mechanisms of actions have also been described. We have previously reported that VA extracts elicited growth inhibitory activities in human estrogen receptor-positive (ER(+)) cells (MCF-7 cells) and ductal carcinoma cells (BT-549) in vitro. The active components in the organic solvent (chloroform)-extracted VA have been previously determined. However, the active components in the ethanolic extracts of VA have not been previously studied. Hence, the objectives of this study are to isolate and characterize the active components of the ethanolic extracts of VA using liquid-liquid extraction, thin layer chromatography and column techniques. Fractionation of the ethanolic extracts of VA yielded three fractions named A1, A2 and A3, and A2 retained the DNA synthesis-inhibitory activity of the extracts. Subsequent fractionation of A2 yielded fraction A2B whose activity was 16 and three times more potent than the ethanolic fraction and fraction A2, respectively. The treatment of cells with 100 μg/mL of either the ethanolic VA extracts, fraction A2 or fraction A2B resulted in a 23% (P < 0.01), 86% (P < 0.0001) and 97% (P < 0.0001) inhibition of DNA synthesis compared with vehicle-treated controls, respectively. Further purification of A2B by high-speed countercurrent chromatography and confirmed by spectroscopic analysis revealed that the major active components of A2B (65% by weight) were steroid glucosides.
苦艾（Vernonia amygdalina）在热带非洲被广泛用于药用和食用。VA 提取物具有许多健康益处（抗氧化、抗菌、抗癌活性等），其作用机制也已被描述。我们之前曾报道过，VA 提取物在体外对人雌激素受体阳性（ER(+））细胞（MCF-7 细胞）和导管癌细胞（BT-549）表现出生长抑制活性。之前已经确定了有机溶剂（氯仿）提取的 VA 中的活性成分。然而，VA 乙醇提取物中的活性成分尚未进行过研究。因此，本研究的目的是使用液液萃取、薄层层析和柱层析技术分离和鉴定 VA 乙醇提取物中的活性成分。VA 乙醇提取物的分级分离得到了三个馏分，分别命名为 A1、A2 和 A3，A2 保留了提取物的 DNA 合成抑制活性。A2 的进一步分级分离得到了 A2B 馏分，其活性分别比乙醇提取物和 A2 馏分高 16 倍和 3 倍。用 100μg/ml 的乙醇 VA 提取物、A2 馏分或 A2B 馏分处理细胞，与载体处理的对照组相比，DNA 合成分别抑制了 23%（P<0.01）、86%（P<0.0001）和 97%（P<0.0001）。通过高速逆流色谱进一步纯化 A2B，并通过光谱分析证实，A2B 的主要活性成分（重量的 65%）为甾体糖苷。
