A "flavone-polysaccharide" redefined as a mixture of 6-methoxyluteolin penta- and hexa-O-glycosides.
The incomplete structure proposed in 1972 for a unique "flavone-polysaccharide" compound, MF-1, from the liverwort Monoclea forsteri, has been re-examined. Rather than the proposed 8-methoxyluteolin structure with polysaccharides attached to the 7- and 4'-hydroxyls, MF-1 has been shown to be primarily a mixture of penta- and hexa-O-glycosides of 6-methoxyluteolin, which are accompanied by their luteolin analogues. MS and NMR evidence is marshalled to define the structure of MF-la as 6-methoxyluteolin 7-O-[2-O-alpha-rhamnosyl-3-O-alpha-arabinosyl-beta-glucuronide]-4'-O-[2-O-alpha-rhamnosyl-3-O-beta-xylosyl-beta-glucuronide], and MF-1b as 6-methoxyluteolin 7-O-[2-O-alpha-rhamnosyl-beta-glucuronide]-4'-O-[2-O-alpha-rhamnosyl-3-O-beta-xylosyl-beta-glucuronide]. This report is the first to provide substantive evidence for the existence of flavone penta- and hexa-O-glycosides in nature. The newly defined structure(s) for MF-1 more closely align M. forsteri with the only other species in the order Monocleales, M. gottschei.
Markham
Kenneth R
KR
Industrial Research Ltd., PO Box 31310, Lower Hutt, New Zealand. k.markham@irl.cri.nz
D005419:Flavonoids / Q000737:chemistry*; D006027:Glycosides / Q000737:chemistry*; D035926:Hepatophyta / Q000737:chemistry* / Q000145:classification; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D015394:Molecular Structure; D011134:Polysaccharides / Q000737:chemistry*
C477204:6-methoxyluteolin 7-O-(2-O-alpha-rhamnosyl-3-O-alpha-arabinosyl-beta-glucuronide)-4'-O-(2-O-alpha-rhamnosyl-3-O-beta-xylosyl-beta-glucuronide); D005419:Flavonoids; D006027:Glycosides; D011134:Polysaccharides