| Summary: | 碩士 === 國立中興大學 === 生物化學研究所 === 101 === In folk medicine, Origanum vulgare is often considered having antibiotic, anti-inflammatory, antioxidant and antitumor activities. However, the efficacy of Origanum vulgare as mentioned above has not yet been proved by scientific process. Our research aimed to investigate the antitumor activities and its molecular mechanisms of essential oils extracted from Origanum vulgare. The major component, p-cymene, of essential oils of Origanum vulgare was analyzed by gas chromatography-mass spectrometry. MTT assay was used to measure the cytotoxicity of essential oils of Origanum vulgare in several cancer cell lines. Among them, the essential oils of Origanum vulgare exhibited high cytotoxicity on H1299 cell line. The IC50 values for H1299 cells was 69±1.5 μg/ml after 24 hrs treatment. The cytotoxic effects of essential oils on H1299 were examined at dose- and time-dependent manners. The flow cytometry analysis showed that the essential oils of Origanum vulgare caused G1 phase cell cycle arrest in H1299 cells. In addition, the annexin-V/Propidium iodide double staining analysis showed that the early apoptosis in H1299 was induced with 24 hrs treatment of the essential oils of Origanum vulgare. Furthermore, we confirmed that essential oils of Origanum vulgare caused G1 phase cell cycle arrest in H1299 through diminishing the expression level of cyclin D1 and cyclin E with Western blotting method. The Western blot also showed that essential oils induced pro-apoptotic Bax to facilitate the cytochrome c releasing from mitochondria to the cytosol. The above results activated caspase-8 and caspase-9, which in turn activated the caspase-3 and PARP cleavage, ultimately led H1299 cells to apoptosis. Our findings suggested that the essential oils extracted from Origanum vulgare inhibited the growth of human non-small-cell lung cancer cells, and induced the activation of caspase-dependent proteins which led to cell apoptosis.
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