title: A new naphthopyrone derivative from Cassia quinquangulata and structural revision of quinquangulin and its glycosides.
abstract: A novel naphthopyrone derivative, named quinquangulone (1), has been isolated from Cassia quinquangulata, along with the known compounds quinquangulin (2) and its two glycosides (3 and 4), rubrofusarin (5) and its two glycosides (6 and 7), nor-rubrofusarin (8) and its 6-O-glucoside (9), and three stilbenes (10-12). The structure of quinquangulone was established by spectral interpretation as 5,9-dihydroxy-8-methoxy-2,9-dimethyl-6-oxo-4H,6H,9H-naphtho-[2,3-b]pyran-4-one. Reinvestigation of the NMR spectra of quinquangulin led to revision of its structure as 5,6-dihydroxy-8-methoxy-2,9-dimethyl-4H-naphtho[2,3-b]pyran-4-one (2a). The structures of two quinguangulin glycosides, 3 and 4, were also revised accordingly. Compound 2a exhibited activity against Staphylococcus aureus and methicillin-resistant S. aureus (MIC, 3.125 and 6.25 microg/mL, respectively).
authors.affiliation: National Center for Natural Products Research, Research Institute of Pharmaceutical Sciences, The University of Mississippi, University, MS 38677, USA.
authors.forename: X C
authors.initials: XC
authors.lastname: Li
authors.forename: D C
authors.initials: DC
authors.lastname: Dunbar
authors.forename: H N
authors.initials: HN
authors.lastname: ElSohly
authors.forename: M R
authors.initials: MR
authors.lastname: Jacob
authors.forename: A C
authors.initials: AC
authors.lastname: Nimrod
authors.forename: L A
authors.initials: LA
authors.lastname: Walker
authors.forename: A M
authors.initials: AM
authors.lastname: Clark
mesh_terms: D000900:Anti-Bacterial Agents; D000890:Anti-Infective Agents / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D001232:Aspergillus fumigatus / Q000187:drug effects; D002176:Candida albicans / Q000187:drug effects; D002366:Cassia / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid; D002855:Chromatography, Thin Layer; D003455:Cryptococcus neoformans / Q000187:drug effects; D004352:Drug Resistance, Microbial; D005960:Glucosides / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D006027:Glycosides / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D009682:Magnetic Resonance Spectroscopy; D016106:Methicillin Resistance; D008826:Microbial Sensitivity Tests; D008968:Molecular Conformation; D015394:Molecular Structure; D015269:Mycobacterium avium Complex / Q000187:drug effects; D009284:Naphthols / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D010568:Peru; D018517:Plant Roots / Q000737:chemistry; D010944:Plants; D010946:Plants, Medicinal / Q000737:chemistry; D011753:Pyrones / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D021241:Spectrometry, Mass, Electrospray Ionization; D013055:Spectrophotometry, Infrared; D013056:Spectrophotometry, Ultraviolet; D013211:Staphylococcus aureus / Q000187:drug effects
chemical_list: D000900:Anti-Bacterial Agents; D000890:Anti-Infective Agents; D005960:Glucosides; D006027:Glycosides; D009284:Naphthols; D011753:Pyrones; C438325:quinquangulin-6-O-apiofuranosyl(1-6)-glucopyranoside; C438324:quinquangulin-6-O-glucopyranoside; C438323:quinquangulone; C015497:rubrofusarin; C015486:quinquangulin