Browsing by Author "Michael Wink"

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    Biological activities and chemistry of saponins from Chenopodium quinoa Willd.
    (2009) Tiwatt Kuljanabhagavad; Michael Wink; M. Wink; Department of Biology, Institute of Pharmacy and Molecular Biotechnology, University of Heidelberg, Heidelberg 69120, Im Neuenheimer Feld 364, Germany; email: wink@uni-hd.de
    Chenopodium quinoa Willd. is a valuable food source which has gained importance in many countries of the world. The plant contains various bitter-tasting saponins which present an important antinutritional factor. Various triterpene saponins have been reported in C. quinoa including both monodesmosidic and bidesmosidic triterpene saponins of oleanolic acid, hederagenin, phytolaccagenic acid, and serjanic acid as the major aglycones and other aglycones as 3_-hydroxy-23-oxo-olean-12-en-28-oic acid, 3_-hydroxy-27-oxo-olean-12-en-28-oic acid, and 3_, 23_, 30_-trihydroxy-olean-12-en-28-oic acid. A tridesmosidic saponin of hederagenin has also been reported. Here we review the occurrence, analysis, chemical structures, and biological activity of triterpene saponins of C. quinoa. In particular, the mode of action of the mono- and bidesmosidic triterpene saponins and aglycones are discussed. © 2009 Springer Science+Business Media B.V.
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    Occurrence and properties of saponins within the family chenopodiaceae
    (Nova Science Publishers, Inc., 2012) Tiwatt Kuljanabhagavad; Michael Wink; T. Kuljanabhagavad; Bioorganic Chemistry Research Laboratories, Faculty of Science and Technology, Suan Dusit Rajabhat University, Bangplad District, Bangkok 10700, 228-228/1-3 Sirithon Road, Thailand; email: ktiwatt@gmail.com
    [No abstract available]
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    Triterpene saponins from Chenopodium quinoa Willd.
    (2008) Tiwatt Kuljanabhagavad; Piyanut Thongphasuk; Walee Chamulitrat; Michael Wink; M. Wink; Department of Biology, Institute of Pharmacy and Molecular Biotechnology, University of Heidelberg, D-69120 Heidelberg, Im Neuenheimer Feld 364, Germany; email: wink@uni-hd.de
    Twenty triterpene saponins (1-20) have been isolated from different parts of Chenopodium quinoa (flowers, fruits, seed coats, and seeds) and their structures have been elucidated by analysis of chemical and spectroscopic data including 1D- and 2D-NMR. Four compounds (1-4) were identified: 3_-[(O-_-d-glucopyranosyl-(1 _ 3)-_-l-arabinopyranosyl)oxy]-23-oxo-olean-12-en-28-oic acid _-d-glucopyranoside (1), 3_-[(O-_-d-glucopyranosyl-(1 _ 3)-_-l-arabinopyranosyl)oxy]-27-oxo-olean-12-en-28-oic acid _-d-glucopyranoside (2), 3-O-_-l-arabinopyranosyl serjanic acid 28-O-_-d-glucopyranosyl ester (3), and 3-O-_-d-glucuronopyranosyl serjanic acid 28-O-_-d-glucopyranosyl ester (4). The following known compounds have not previously been reported as saponin constituents from the flowers and the fruits of this plant: two bidesmosides of serjanic acid (5, 6), four bidesmosides of oleanolic acid (7-10), five bidesmosides of phytolaccagenic acid (11-15), four bidesmosides of hederagenin (16-19), and one bidesmoside of 3_,23,30-trihydroxy olean-12-en-28-oic acid (20). The cytotoxicity of these saponins and their aglycones was tested in HeLa cells. Induction of apoptosis in Caco-2 cells by bidesmosidic saponins 1-4 and their aglycones I-III was determined by flow cytometric DNA analysis. The saponins with an aldehyde group were most active. The relationships between structure and cytotoxic activity of saponins and their aglycones are discussed. © 2008.