| Summary: | 博士 === 高雄醫學大學 === 天然藥物研究所博士班 === 103 === The investigation of the chemical constituents of herbal medicines and the demonstration of their pharmacological activities are crucial to provide scientific evidence to medical and folk uses. The distinctive geographical nature, rich history, and biodiversity of Taiwan offer a superior advantage for the research and development of drugs from natural products.
Initially, we tried to establish a new model for screening estrogen-like substances. The application of the transgenic pER8:GUS Arabidopsis callus in a cross-kingdom assay to evaluate
the estrogenic activity of 17β-estradiol (E2) and natural products is discussed for the first time. The transgenic plants were utilized to produce a large number of calli, which stably expressed transfer
genes by asexual reproduction. The optimum formula for calli induction and production were selected from sixteen solid media and six liquid media, respectively. The solid medium 1DK1
induced the largest number of healthy calli, which showed dose-dependent GUS activity in the histochemical and fluorometric assay. Therefore, 1DK1 calli were selected for further optimization
for the suspension culture. The calli of liquid media &;#617;1N1B and &;#617;1/2 1N1B exhibited significant sensitivity towards E2 in a dose-dependent manner as demonstrated by the histochemical and
fluorometric assay. This protocol can be used to detect the estrogenic activity of secondary metabolites, environmental waste products, pesticides and other substances interacting with
estrogenic receptors. It can be also used in the evaluation of nutritional supplements and candidate drugs possessing estrogenic activity.
This study also focuses on natural product chemistry and their bioactivities of native Taiwanese herbs, Liriope platyphylla (Liliaceae) and Lindernia crustacea (Scrophulariaceae). Phytochemical investigation of L. platyphylla ethanolic extract led to the isolation of thirty-eight components, including eight new compounds (1&;#8210;8) and thirty known compounds (9&;#8210;38). Those isolates were summarized in twelve skeletons, including phenyl-isocoumarin (1), benzofuroisocoumarins (2&;#8210;4), benzyl-benzofuran (5), ethyl butanoate (3), homoisoflavonoids (7&;#8210;14), chalcone (15), flavonoids (16&;#8210;25), amides (26&;#8210;31), lignan (32), fatty acid derivative (33 and 34), indole (35), and benzenoids (36&;#8210;38). Compounds 9, 11, 19, and 22 exhibited the most potent estrogenic activity in a dose-dependent manner, rendering those compounds and similar structures as potential candidates for phytoestrogen nutritional supplements. Furthermore, compounds 11 and 12 showed the highest inhibitory activity in platelet aggregation assay. Our results provided the first insight of L. platyphylla active components with estrogenic and antiplatelet activities suggesting the potential utilization of this herb and other components in dietary supplements and functional food products.
Phytochemical investigation of the other herb, L. crustacea ethanolic extract resulted in the isolation of thirty-three compounds. Those isolates were classified as a diterpene (39), four anthraquinone (40&;#8210;43), two iridoides (44 and 45), fourteen phenylpropanoid glycosides (46&;#8210;59), five flavonoids (60&;#8210;64), a lignan glycoside (65), a phenethyl alcohol glycoside (66), a
phenylpropene glycoside (67), a glucosylglycerol derivative (68), a furanone (69), and two cinnamic acid derivatives (70 and 71). Compounds 39, 40, 44–64, 66, 68, and 71 were evaluated
for their anti-Epstein-Barr virus (EBV) activity. Compounds 39, 40, 45–49, 62, and 63 exhibited significant inhibitory effect on EBV lytic cycle in immunoblot analysis, while 44, 50, and 51 showed moderate anti-EBV activity. This is the first phytochemical and biological investigation of L. crustacea. All isolates were identified for the first time from Lindernia sp.
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