Kaempferol-3-O-glucosyl(1-2)rhamnoside from Ginkgo biloba and a reappraisal of other gluco(1-2, 1-3 and 1-4)rhamnoside structures.
A kaempferol-3-O-glucorhamnoside from Ginkgo biloba is defined as the 3-O-alpha-L-[ beta-D-glucopyranosyl(1-2)rhamnopyranoside] on the basis of 2D NMR evidence. Complete assignments of the 1H and 13C NMR spectra of this compound and of its known p-coumaroyl derivative are presented for the first time. The NMR distinctions of 1-2, 1-3 and 1-4 linked glucopyranosylrhamnopyranosides are discussed and indicate (i) that the 13C NMR assignments for one published gluco(1-3)rhamnoside are in need of modification, (ii) that the published structure of hordenine-O-[6-O-t-cinnamoyl-beta-glucosyl(1-4)-alpha-rhamnoside] from Selaginella doederleinii is not distinguished from the 1-3 linked glucorhamnoside structure, and (iii) that the 8-prenylkaempferol-3-O-[glucosyl(1-4)rhamnoside]-7-O-glucoside and the equivalent 4'-O-methylated xylosyl(1-4)rhamnoside from Epimedium pubescens and E. washanense, respectively, are (1-2)-linked.
Markham
K R
KR
DSIR-Chemistry, Petone, New Zealand.
Geiger
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H
Jaggy
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D002240:Carbohydrate Sequence; D005419:Flavonoids; D005960:Glucosides / Q000737:chemistry / Q000302:isolation & purification*; D006027:Glycosides / Q000737:chemistry / Q000302:isolation & purification*; D044949:Kaempferols; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data; D010944:Plants / Q000737:chemistry*; D011794:Quercetin / Q000031:analogs & derivatives* / Q000737:chemistry / Q000302:isolation & purification
D005419:Flavonoids; D005960:Glucosides; D006027:Glycosides; D044949:Kaempferols; C074176:kaempferol-3-O-glucosyl(1-2)rhamnoside; D011794:Quercetin