George V Cijo, Kumar D R Naveen, Suresh P K, Kumar R Ashok
School of Bio Sciences and Technology, VIT University, Vellore, India E-mail :
Asian Pac J Cancer Prev. 2012;13(5):2015-20. doi: 10.7314/apjcp.2012.13.5.2015.
Oleanolic acid (OA) is a naturally occurring triterpenoid in food materials and is a component of the leaves and roots of Olea europaea, Viscum album L., Aralia chinensis L. and more than 120 other plant species. There are several reports validating its antitumor activity against different cancer cells apart from its hepatoprotective activity. However, antitumor activity against skin cancer has not been studied well thus far. Hence the present study of effects of OA against HaCaT (immortalized keratinocyte) cells--a cell-based epithelial model system for toxicity/ethnopharmacology-based studies--was conducted. Radical scavenging activity (DPPH·) and FRAP were determined spectrophotometrically. Proliferation was assessed by XTT assay at 24, 48 and 72 hrs with exposure to various concentrations (12.5-200 μM) of OA. Apoptotic induction potential of OA was demonstrated using a cellular DNA fragmentation ELISA method. Morphological studies were also carried out to elucidate its antitumor potential. The results revealed that OA induces apoptosis by altering cellular morphology as well as DNA integrity in HaCaT cells in a dose-dependent manner, with comparatively low cytotoxicity. The moderate toxicity observed in HaCaT cells, with induction of apoptosis, possibly suggests greater involvement of programmed-cell death-mediated mechanisms. We conclude that OA has relatively low toxicity and has the potential to induce apoptosis in HaCaT cells and hence provides a substantial and sound scientific basis for further validation studies.
齐墩果酸（OA）是一种天然存在于食物中的三萜类化合物，是油橄榄、槲寄生、楤木等120多种植物的叶和根的组成成分。除了具有肝脏保护活性外，还有几份报告证实了其对不同癌细胞的抗肿瘤活性。然而，到目前为止，其对皮肤癌的抗肿瘤活性尚未得到充分研究。因此，本研究开展了OA对HaCaT细胞（一种用于毒性/基于民族药理学研究的细胞系上皮模型系统）作用的研究。通过分光光度法测定自由基清除活性（DPPH·）和铁还原抗氧化能力（FRAP）。在暴露于不同浓度（12.5 - 200μM）的OA下，于24、48和72小时通过XTT法评估细胞增殖。使用细胞DNA片段化ELISA方法证明OA的凋亡诱导潜力。还进行了形态学研究以阐明其抗肿瘤潜力。结果显示，OA以剂量依赖的方式通过改变HaCaT细胞的细胞形态以及DNA完整性来诱导凋亡，且细胞毒性相对较低。在HaCaT细胞中观察到的中度毒性以及凋亡诱导，可能表明程序性细胞死亡介导的机制参与度更高。我们得出结论，OA具有相对较低的毒性，并且有潜力在HaCaT细胞中诱导凋亡，因此为进一步的验证研究提供了坚实可靠的科学依据。
