title: Pentameric ellagitannin oligomers in melastomataceous plants--chemotaxonomic significance.
abstract: The pantropical plant family Melastomataceae produces characteristic hydrolyzable tannin oligomers. The latter in this family are distinguished from those in other plant families by the fact that the oligomers from dimers to tetramers are composed of two different alternating monomeric units: casuarictin and pterocaryanin C. These oligomers are metabolites that are produced by intermolecular C-O oxidative coupling between the monomers (or their desgalloyl-or des-hexahydroxydiphenoyl derivatives) forming a valoneoyl group as the link between monomers. The chemotaxonomically significant oligomerization pattern of melastomataceous plants provided helpful suggestions for determining the structures of new oligomers (nobotanins Q-T and melastoflorins A-D) isolated from Monochaetum multiflorum, which belongs to this family. Melastoflorins A-D were characterized as pentamers, which are the largest hydrolyzable tannins composed of different monomeric units.
authors.affiliation: Department of Pharmacognosy, Faculty of Pharmaceutical Sciences, Okayama University, Tsushima, Okayama 700-8530, Japan. yoshida@pharm.okayama-u.ac.jp
authors.forename: Takashi
authors.initials: T
authors.lastname: Yoshida
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Ito
authors.forename: Isaza Jose
authors.initials: IJ
authors.lastname: Hipolito
mesh_terms: D001704:Biopolymers / Q000737:chemistry*; D002240:Carbohydrate Sequence; D047348:Hydrolyzable Tannins / Q000737:chemistry*; D008969:Molecular Sequence Data; D015394:Molecular Structure; D010944:Plants / Q000737:chemistry* / Q000145:classification; D013057:Spectrum Analysis / Q000379:methods
chemical_list: D001704:Biopolymers; D047348:Hydrolyzable Tannins; C013515:ellagitannin