| Summary: | 碩士 === 台北醫學院 === 生藥學研究所 === 90 === Abstract
Gynura formosana Kiamnra (Compositae) is a folkic herbal medicine in Taiwan. G. formosana was popular used as vegetable and to treat the hypertension, diabetes mellitus, cerebral infarction etc. In the screening test with FeCl3 T.S. reagent, scavenging activity of DPPH activity, and reducing power, it implied G. formosana is the potential condidate developing to the natural health food because of its scavenging activities. Thus, the herb of G. formosana was extract with 70% aqueous acetone, then isolated chemical components by using both FeCl3 T.S. and bio-guide. The 70% aqueous acetone extract was chromatographed over Diaion HP20, Toyopearl HW40(C), MCI CHP 20P, Sephadex LH20, ODS (Octadecylsilane) columns, and purified by HPLC (high performance liguid chromatography) to yield four compounds, compound 1 to 4. The structures were identified by chemical reactions and spectroscopic methods. Compound 1 to 4 are characterized as quercetin 3-O-rutinoside (rutin) (1), caffeic acid (2), kaempferol 3-O-rutinoside (nicotoflorin) (3), and kaempferol 3-O-robinobioside (4), respectively. The IC50 value of quercetin 3-O-rutinoside (rutin) (1) was 2.3 μg/mL on DPPH (1,1-diphenyl-2- picrylhydrazy) free radical scavenging activity. And reducing power of (quercetin 3-O-rutinoside) rutin (1) was also the showed the best activity. In the EPR analysis, rutin (1), kaempferol 3-O-rutinoside (nicotoflorin) (3), and kaempferol 3-O-robinobioside(4) were showed the scavenging activities of DPPH free radicals in a dose-dependent manner. In this study, the four phenolic components were isolated from G. formosana and exhibit the free radicals activity. Therefore, G. formosana may be develop to the health food in the future.
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