title: Flavonoids from Andrographis viscosula.
abstract: Phytochemical investigation of the whole plant of Andrographis viscosula has led to the isolation of three new 2'-oxygenated flavonoids, (2R)-5-hydroxy-7,2',3'-trimethoxyflavanone (1), 7,2',5'-trimethoxyflavone (2), 5,7,2',3'-tetramethoxyflavone (3), and eight known flavones, 5,7,2'-trimethoxyflavone (4), 5,7,2',4',5'-pentamethoxyflavone (5), echioidinin (6), 5,2',6'-trihydroxy-7-methoxyflavone (7), 5-hydroxy-7,2'-dimethoxyflavone (8), echioidin (9), echioidinin 5-O-glucoside (10), and 5,2',6'-trihydroxy-7-methoxyflavone 2'-O-glucoside (11). The structures of 1-11 were elucidated by physical and spectral methods, including extensive 2D NMR studies. The presence of 2'-oxygenated flavonoids is apparently restricted to Andrographis species in Acanthaceae. Therefore, 2'-oxygenated flavonoids are regarded as chemotaxonomic markers of Andrographis genus in the Acanthaceae family.
authors.affiliation: Natural Products Division, Department of Chemistry, Sri Venkateswara University, Tirupati, India.
authors.forename: Yerra Koteswara
authors.initials: YK
authors.lastname: Rao
authors.forename: Amooru Gangaiah
authors.initials: AG
authors.lastname: Damu
authors.forename: Alahari Janardhan
authors.initials: AJ
authors.lastname: Rao
authors.forename: Shanmuganathan
authors.initials: S
authors.lastname: Venkatesan
authors.forename: Ping-Chung
authors.initials: PC
authors.lastname: Kuo
authors.forename: Chunduri Venkata
authors.initials: CV
authors.lastname: Rao
authors.forename: Tian-Shung
authors.initials: TS
authors.lastname: Wu
mesh_terms: D035685:Andrographis; D005419:Flavonoids / Q000737:chemistry* / Q000302:isolation & purification*; D010936:Plant Extracts / Q000737:chemistry / Q000302:isolation & purification; D018514:Plant Structures
chemical_list: D005419:Flavonoids; D010936:Plant Extracts