title: Flavones and flavone glycosides from Halophila johnsonii.
abstract: Halophila johnsonii Eiseman is a shallow-water marine angiosperm which contains UV-absorbing metabolites. Studies on methanol extracts of H. johnsonii by means of HPLC-UV, NMR, HPLC-MS resulted in isolation and identification of seven previously unknown flavone glycosides: 5,6,7,3',4',5'-hexahydroxyflavone-7-O-beta-glucopyranoside (1), 5,6,7,3',4',5'-hexahydroxyflavone-7-O-(6''-O-acetyl)-beta-glucopyranoside (2), 6-hydroxyluteolin-7-O-(6''-O-acetyl)-beta-glucopyranoside (3), 6-hydroxyapigenin-7-O-(6''-O-acetyl)-beta-glucopyranoside (4), 6-hydroxyapigenin-7-O-(6''-O-[E]-coumaroyl)-beta-glucopyranoside (5), 6-hydroxyapigenin-7-O-(6''-O-[E]-caffeoyl)-beta-glucopyranoside (6) and 6-hydroxyluteolin-7-O-(6''-O-[E]-coumaroyl)-beta-glucopyranoside (7). Also isolated were three known flavone glycosides, 6-hydroxyluteolin 7-O-beta-glucopyranoside (8), scutellarein-7-O-beta-glucopyranoside (9), and spicoside (10), and five known flavones, pedalitin (11), ladanetin (12), luteolin (13), apegenin (14) and myricetin (15). Qualitative comparison of the flavonoid distribution in the leaf and rhizome-root portions of the plant was also investigated, with the aim of establishing the UV-protecting roles that flavonoids played in the sea grass.
authors.affiliation: Center for Marine Science, University of North Carolina at Wilmington, 5600 Marvin Moss Lane, Wilmington, NC 28409, United States.
authors.forename: Yanhui
authors.initials: Y
authors.lastname: Meng
authors.forename: Amanda J
authors.initials: AJ
authors.lastname: Krzysiak
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Durako
authors.forename: Jennifer I
authors.initials: JI
authors.lastname: Kunzelman
authors.forename: Jeffrey L C
authors.initials: JL
authors.lastname: Wright
mesh_terms: D002851:Chromatography, High Pressure Liquid; D047309:Flavones; D005419:Flavonoids / Q000737:chemistry* / Q000302:isolation & purification; D006027:Glycosides / Q000737:chemistry* / Q000302:isolation & purification; D031321:Hydrocharitaceae / Q000737:chemistry* / Q000528:radiation effects; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D010936:Plant Extracts / Q000737:chemistry; D018515:Plant Leaves / Q000737:chemistry; D027343:Rhizome / Q000737:chemistry; D014466:Ultraviolet Rays
chemical_list: D047309:Flavones; D005419:Flavonoids; D006027:Glycosides; D010936:Plant Extracts; C043562:flavone