title: Chemical composition of shallot (Allium ascalonicum Hort.).
abstract: An extensive phytochemical analysis of the polar extracts from bulbs of shallot, Allium ascalonicum Hort., led to the isolation of two new furostanol saponins, named ascalonicoside A1/A2 (1a/1b) and ascalonicoside B (4), respectively, along with compounds 2a and 2b, most likely extraction artifacts. On the basis of 2D NMR and mass spectrometry data, the structures of the novel compounds were elucidated as furost-5(6)-en-3beta,22alpha-diol 1beta-O-beta-D-galactopyranosyl 26-O-[alpha-L-rhamnopyranosyl-(1-->2)-O-beta-D-glucopyranoside] (1a), its epimer at position 22 (1b), and furost-5(6),20(22)-dien-3beta-ol 1beta-O-beta-D-galactopyranosyl 26-O-[alpha-L-rhamnopyranosyl-(1-->2)-O-beta-D-glucopyranoside] (4). This is the first report of furostanol saponins in A. ascalonicum. High concentrations of quercetin, isorhamnetin, and their glycosides were also isolated and described.
authors.affiliation: Dipartimento di Chimica delle Sostanze Naturali, Università di Napoli Federico II, Via D. Montesano 49, Italy.
authors.forename: Ernesto
authors.initials: E
authors.lastname: Fattorusso
authors.forename: Maria
authors.initials: M
authors.lastname: Iorizzi
authors.forename: Virginia
authors.initials: V
authors.lastname: Lanzotti
authors.forename: Orazio
authors.initials: O
authors.lastname: Taglialatela-Scafati
mesh_terms: D000490:Allium / Q000737:chemistry*; D044948:Flavonols; D006027:Glycosides / Q000032:analysis; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D015394:Molecular Structure; D010936:Plant Extracts / Q000737:chemistry*; D011794:Quercetin / Q000031:analogs & derivatives* / Q000032:analysis; D012503:Saponins / Q000032:analysis; D016339:Spectrometry, Mass, Fast Atom Bombardment
chemical_list: D044948:Flavonols; D006027:Glycosides; D010936:Plant Extracts; D012503:Saponins; C047368:3-methylquercetin; D011794:Quercetin