title: A new phenanthrenequinone from Dendrobium draconis.
abstract: A number of Dendrobium species (Orchidaceae) have been used as health foods. In Thailand, the tea prepared from the stems of Dendrobium draconis Rchb.f. (Orchidaceae) has been used as a blood tonic. Our phytochemical investigation of this plant led to the isolation of a new compound namely 5-methoxy-7-hydroxy-9,10-dihydro-1,4-phenanthrenequinone, along with four known stilbenoids including hircinol, gigantol, batatasin III, and 7-methoxy-9,10-dihydrophenanthrene-2,4,5-triol. The structures of these compounds were determined through extensive spectroscopic studies, including (1)H and (13)C NMR, DEPT, COSY, NOESY, HMQC, HMBC, ESI-MS, and HR-ESI-MS experiments. In the DPPH-free radical assay, these stilbene derivatives showed appreciable antioxidant activity.
authors.affiliation: Department of Pharmacognosy and Pharmaceutical Botany, Faculty of Pharmaceutical Sciences, Chulalongkorn University, Bangkok, Thailand.
authors.forename: Boonchoo
authors.initials: B
authors.lastname: Sritularak
authors.forename: Mutita
authors.initials: M
authors.lastname: Anuwat
authors.forename: Kittisak
authors.initials: K
authors.lastname: Likhitwitayawuid
mesh_terms: D000975:Antioxidants / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D031667:Dendrobium / Q000737:chemistry*; D015394:Molecular Structure; D019906:Nuclear Magnetic Resonance, Biomolecular; D010616:Phenanthrenes / Q000737:chemistry / Q000302:isolation & purification*; D013267:Stilbenes / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology
chemical_list: C558197:5-methoxy-7-hydroxy-9,10-dihydro-1,4-phenanthrenequinone; D000975:Antioxidants; D010616:Phenanthrenes; D013267:Stilbenes; C105959:1,4-phenanthrenequinone