title: Two benzophenone O-arabinosides and a chromone from Hypericum annulatum.
abstract: Two benzophenone O-arabinosides, annulatophenonoside (1) and acetylannulatophenonoside (2) were isolated from the methanol extract of the herb of Hypericum annulatum. The structures of the benzophenones were established as 2-O-alpha-L-arabinofuranosyl-3',5',6-trihydroxy-4-methoxybenzophenone (1) and 2-O-alpha-L-3"-acetylarabinofuranosyl-3',5',6-trihydroxy-4-methoxybenzophenone (2) based on spectral and chemical evidence. A chromone, 5,7-dihydroxy-3-methylchromone (3) was isolated from the chloroform extract. Although it has been previously synthesized it is encountered in a plant source for the first time. Co-occurrence of the two new benzophenone O-arabinosides along with the biogenetically related 1,5,7-trihydroxy-3-methoxyxanthone was not found.
authors.affiliation: Department of Pharmacognosy, Faculty of Pharmacy, Medical University of Sofia, Dunav str. 2, 1000, Sofia, Bulgaria.
authors.forename: Paraskev T
authors.initials: PT
authors.lastname: Nedialkov
authors.forename: Gerassim M
authors.initials: GM
authors.lastname: Kitanov
mesh_terms: D001577:Benzophenones / Q000737:chemistry*; D002867:Chromones / Q000737:chemistry* / Q000302:isolation & purification; D028084:Clusiaceae / Q000737:chemistry*; D006027:Glycosides / Q000737:chemistry* / Q000302:isolation & purification; D010936:Plant Extracts / Q000737:chemistry
chemical_list: D001577:Benzophenones; D002867:Chromones; D006027:Glycosides; D010936:Plant Extracts; C047723:benzophenone