New glycosides from the Japanese fern Hymenophyllum barbatum.
Thirteen glycosides and methyl (3R,5R)-5-hydroxy-(beta-D-glucopyranosyloxy)-hexanoate were newly isolated from the Japanese fern Hymenophyllum barbatum, although our previous work revealed the isolation of hemiterpene glycosides, hymenosides A-J, from the same species. The structures of the newly isolated glycosides were elucidated by extensive two-dimensional (2D) NMR and/or chemical evidence. The structures of those aglycones were divided into four types, 2-methyl-but-2-ene-1,4-diol, 2-hydroxymethyl-but-2-ene-1,4-diol, 2-methylene-butane-1,3,4-triol, and 3-hydroxy-5-hexanolide. The sugar moieties, which were acylated by phenylacetic acid derivatives, were also established by chemical and spectroscopic methods. Eight glucosides of the isolated compounds in the present investigation had a bitter or weakly pungent taste. It is clear that a phenylacetyl group attached to glucose or allose as an ester is necessary for the bitter taste.
Toyota
Masao
M
Faculty of Pharmaceutical Sciences, Tokushima Bunri University, Japan. toyota@ph.bunri-u.ac.jp
Oiso
Yasushi
Y
Asakawa
Yoshinori
Y
D002850:Chromatography, Gel; D002851:Chromatography, High Pressure Liquid; D029624:Ferns / Q000737:chemistry*; D006027:Glycosides / Q000737:chemistry / Q000302:isolation & purification*; D006868:Hydrolysis; D007564:Japan; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D010936:Plant Extracts / Q000737:chemistry
D006027:Glycosides; D010936:Plant Extracts