Browsing by Autor "Nunziatina De Tommasi"

Now showing 1 - 5 of 5

Anadanthoside: a flavanol-3-O-β-d-xylopyranoside from Anadenanthera macrocarpa
(Elsevier BV, 1999) Sonia Piacente; Luisa Balderrama; Nunziatina De Tommasi; L. J. MORALES; L. Rivera Vargas; Cosimo Pìzza
Antioxidant Chalcone Glycosides and Flavanones fromMaclura(Chlorophora)tinctoria
(American Chemical Society, 2003) Giuseppina Cioffi; Luis Morales Escobar; Alessandra Braca; Nunziatina De Tommasi
Four chalcone glycosides (1-4), including three new natural products, and three flavanones (5-7) were isolated from the methanol extract of stem bark of Maclura tinctoria. The new compounds have been characterized as 4'-O-beta-D-(2' '-p-coumaroyl)glucopyranosyl-4,2',3'-trihydroxychalcone (1), 4'-O-beta-D-(2' '-p-coumaroyl-6' '-acetyl)glucopyranosyl-4,2',3'-trihydroxychalcone (2), and 3'-(3-methyl-2-butenyl)-4'-O-beta-D-glucopyranosyl-4,2'-dihydroxychalcone (3); the known derivatives were elucidated as 4'-O-beta-D-(2' '-acetyl-6' '-cinnamoyl)glucopyranosyl-4,2',3'-trihydroxychalcone (4), eriodictyol 7-O-beta-D-glucopyranoside (5), naringenin (6), and naringenin 4'-O-beta-D-glucopyranoside (7). Their structures were determined by 1D and 2D NMR and ESIMS. The antioxidant activity of all the isolated compounds was determined by measuring free-radical-scavenging effects using two different assays, namely, the Trolox Equivalent Antioxidant Capacity (TEAC) assay and the coupled oxidation of beta-carotene and linoleic acid (autoxidation assay). The results showed that compound 3 was the most active in both antioxidant assays.
New Flavonoid Glycosides from Vernonia ferruginea
(SAGE Publishing, 2009) Nicola Malafronte; Maria S. Pesca; Angela Bisio; Luis Morales Escobar; Nunziatina De Tommasi
Four new flavonoid glycosides, quercetin 3-O-beta-D-xylopyranosyl-(1-4)-beta-D-glucopyranoside, quercetin 3-O-beta-D-apiofuranosyl-(1-4)-beta-D-glucopyranoside, kaempferol 3-O-beta-D-apiofuranosyl-(1-4)-beta-D-glucopyranoside, and kaempferol 4'-methyl ether 3-O-beta-D-xylopyranoside, along with other known flavonoids and phenolic derivatives, were isolated from the leaves of Vernonia ferruginea Less. Their structures were established on the basis of detailed spectral analysis.
Phytochemical and Pharmacological Studies ofGuettarda acreana
(Thieme Medical Publishers (Germany), 1998) Anna Capasso; Luisa Balderrama; Sirley Sivila; Nunziatina De Tommasi; L. Sorrentino; Cosimo Pìzza
The present study examines the effects of the extracts [petroleum ether, CHCl3, CHCl3/MeOH (9:1) and MeOH], partially purified fractions and pure compounds from Guettarda acreana on the electrically induced contractions (E.C.I.) of the isolated guinea-pig ileum. The results of the experiments indicate that CHCl3/MeOH (9:1), MeOH extract, and the MeOH soluble part from CHCl3/MeOH extract tested at concentrations of 1.2, 2.5, and 5 micrograms/ml, dose-dependently reduced the guinea-pig ileum contractions. Furthermore, some partially purified fractions I-IV from the MeOH extract, each tested at the same concentrations of the extracts, and some pure compounds (6 x 10(-6), 3 x 10(-6), 1 x 10(-6) M) isolated from the above fractions significantly reduced, in a dose-dependent manner, the electrical contractions of the ileum. The active compounds were identified as the known indole alkaloids strictosidic acid, lyalosidic acid, 5 alpha-carboxystrictosidine, strictosidine, and sickingine, as well as the known quinic acid derivatives 5-caffeoylquinic acid, 4,5-dicaffeoylquinic acid, and shikimic acid by spectral data. Two known quinovic acid glycosides and a new triterpenic glycoside, quinovic acid 3 beta-O-alpha-rhamnopyranosyl-(1-->3)-(beta-glucopyranosyl-(1-->6)-beta- glucopyranoside, were also isolated and their structures established by NMR and M5 data.
Triterpenes and anthraquinones from Picramnia sellowii Planchon in Hook (Simaroubaceae)
(Elsevier BV, 2001) Luisa Balderrama; Alessandra Braca; Emilia García; Marcela Melgarejo; Cosimo Pìzza; Nunziatina De Tommasi