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DOI: 10.1055/s-0036-1596739
Development of chemopreventive agents for hepatocellular carcinoma from Excoecaria formosana by a glycine N-methyltransferase (GNMT) gene expression-oriented screen platform
Publication History
Publication Date:
14 December 2016 (online)
Glycine N-methyltransferase (GNMT) is a tumor suppressor gene for hepatocellular carcinoma (HCC) [1]. The genotypic analysis of GNMT may serve as a marker for preventive and/or occupational healthy consultation. Approximately 1,400 species of Formosan indigenous plants have been screened for the GNMT promotor activity, and the Excoecaria formosana (Hay.) Hay. (Euphorbiaceae) was found to be one of the most bioactive species. E. formosana is a shrub and mainly distributed in Tonkin, Indo-China, southern part of Taiwan in thickets and forests along the seashores [2]. The studies on Excoecaria genus identified various classes of chemical constituents, most of which were diterpenoids, flavonoids, and galloyl glucoses. However, no chemical constituents and bioactivity investigation of E. formosana have been reported. The methanolic extract of the whole plant of E. formosana was partitioned into ethyl acetate, water, and n-butanol-soluble layers. Bioassay-guided fractionation of the active ethyl acetate-soluble layer led to the isolation of one new steroid: 6'-(stigmast-5-en-7-hydroperoxy-3-O-β-glucopyransidyl)hexadecanoate (1) and six known compounds, including four steroids: 6'-(stigmast-5-en-7-one-3-O-β-glucopyransidyl)hexadecanoate (2), (6'-O-palmitoyl)sitosterol -3-O-β-D-glucoside (3), a mixture of β-sitosterol (4) and stigmasterol (5), one diterpenoid: ent-11α-hydroxy-3-oxo-13-epi-manoyl oxide (6), and one benzenoid: methyl gallate (7). The successive isolation of the active subfractions of this plant is still in progress and the isolates are further evaluated with their GNMT promoter activity assay.
Acknowledgements: This study was supported partially by Kaohsiung Medical University “Aim for the Top Universities Grant, grant No. KMU-TP103H01, KMU-TP103H05 and KMU-TP104E43”.
Keywords: Excoecaria formosana, Euphorbiaceae, whole plant, GNMT promoter activity.
References:
[1] Chen YM, Shiu JY, Tzeng SJ, Shih LS, Chen YJ, Lui WY, Chen PH. Characterization of glycine-N-methyltransferase-gene expression in human hepatocellular carcinoma. Int J Cancer 1998; 75: 787 – 793
[2] Hsieh CF, Chaw SM, Wang JC. Euphorbiaceae. In: Flora of Taiwan, Vol. 3, 2nd edition. Taipei, Taiwan: Editorial Committee of the Flora of Taiwan; 1993: 469 – 470
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No conflict of interest has been declared by the author(s).