| Summary: | 碩士 === 國立清華大學 === 分子醫學研究所 === 98 === Tylophora ovata (T. ovata) belongs to phylum Magnoliophyta, class
Dicotyledoneae, order Gentianales, family Asclepiadaceae, and genus Tylophora. Up
to date, botanists have found about 60 species of Tylophora all over the world. Since
the first isolation of tylophorine from Tylophora indica in A.D. 1935, many kinds of
phenanthroindolizidine or phenanthroquinolizidine alkaloids have been isolated and
purified from Asclepiadaceae, especially from Tylophora and Cynanchum. These
alkaloids have been shown to exert anti-leukemia, anti-asthma, anti-anaphylactic,
anti-bacterial and other anti-inflammatory activities. Last decade, they have regained
attentions for development into therapeutic agents with well known cytotoxic activity
against a variety of cancer cell lines in vitro and in vivo. T. ovata is most commonly
distributed species of tylophora plants native to Taiwan than the other two species, T.
oshimae Hayata and T. taiwanensis Hatusima). In order to investigate the tylophorine
analogous ingredients from T. ovata, we collected T. ovata plant materials for
isolation and purification of tylophorine analogues. The air-dried leaves and stems
were extracted with MeOH at boiling point under reflux and then concentrated to
green-brown gummy residues, respectively. The residues in 0.5% HCl-soluble
portions were filtered. The filtrates were made alkaline with 25% NH4OH (pH=9),
and extracted repeatedly with CHCl3 until the organic layer exhibited Dragendorff test
was negative. Subsequently, a series of chromatography including open silica gel
column and preparative high pressure liquid chromatography were applied for
purification. EI-MS, 1H-NMR, 13C-NMR, DEPT, 2D-NMR, IR, and [α] were
exploited to identify the structures of the 12 compounds from the leaves and the stems
of T. ovata. They are (S)-(+)-tylophorine, (S)-(+)-septicine, (+)-tylophorinine,
(+)-tylophorincine, (-)-tylophorincine, (S)-(+)-hispidine,
(S)-(+)-2,6-didesmethoxyl-4-hydroxyl-septicine, (S)-(+)-6-desmethylsepticine,
(S)-(+)-6-desmethyltylophorine, (S)-(+)-3-desmethyisotylocrebrine,
trans-(+)-3,14α-dihydroxy-4,6,7-trimethoxyphenanthroindolizidine, and
trans-(+)-3,14α-dihydroxy-6,7-dimethoxyphenanthroindolizidine.
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