title: α-Glucosidase inhibition and antioxidant activity of an oenological commercial tannin. Extraction, fractionation and analysis by HPLC/ESI-MS/MS and (1)H NMR.
abstract: Two batches of the oenological tannin Tan'Activ R, (toasted oak wood - Quercus robur), were extracted with ethanol. A fractionation on XAD-16 afforded four fractions for each extract. Extracts and fractions were evaluated for antioxidant activity (DPPH), polyphenol content (GAE) and yeast α-glucosidase inhibitory activity. Comparable results were obtained for both columns, fractions X1B and X2B showing the highest antioxidant activity. Fractions X1C and X2C notably inhibited α-glucosidase, with IC50=9.89 and 8.05μg/mL, respectively. Fractions were subjected to HPLC/ESI-MS/MS and (1)H NMR analysis. The main phenolic constituents of both X1B and X2B were a monogalloylglucose isomer (1), a HHDP-glucose isomer (2), castalin (3) gallic acid (4), vescalagin (5), and grandinin (or its isomer roburin E, 6). X1C and X2C showed a complex composition, including non-phenolic constituents. Fractionation of X2C gave a subfraction, with enhanced α-glucosidase inhibitory activity (IC50=6.15μg/mL), with castalagin (7) as the main constituent.
authors.affiliation: Dipartimento di Scienze Chimiche, Università degli Studi di Catania, V.le A. Doria 6, 95125 Catania, Italy. Electronic address: v.muccilli@unict.it.
authors.forename: Vera
authors.initials: V
authors.lastname: Muccilli
authors.affiliation: Dipartimento di Scienze Chimiche, Università degli Studi di Catania, V.le A. Doria 6, 95125 Catania, Italy. Electronic address: ncardullo@unict.it.
authors.forename: Nunzio
authors.initials: N
authors.lastname: Cardullo
authors.affiliation: Dipartimento di Scienze Chimiche, Università degli Studi di Catania, V.le A. Doria 6, 95125 Catania, Italy. Electronic address: cspatafo@unict.it.
authors.forename: Carmela
authors.initials: C
authors.lastname: Spatafora
authors.affiliation: Dipartimento di Scienze Chimiche, Università degli Studi di Catania, V.le A. Doria 6, 95125 Catania, Italy. Electronic address: vcunsolo@unict.it.
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Cunsolo
authors.affiliation: Dipartimento di Scienze Chimiche, Università degli Studi di Catania, V.le A. Doria 6, 95125 Catania, Italy. Electronic address: ctringali@unict.it.
authors.forename: Corrado
authors.initials: C
authors.lastname: Tringali
mesh_terms: D000975:Antioxidants; D005591:Chemical Fractionation / Q000379:methods*; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D065089:Glycoside Hydrolase Inhibitors / Q000032:analysis*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D059808:Polyphenols / Q000032:analysis*; D053719:Tandem Mass Spectrometry / Q000379:methods*; D013634:Tannins / Q000032:analysis / Q000737:chemistry*
chemical_list: D000975:Antioxidants; D065089:Glycoside Hydrolase Inhibitors; D059808:Polyphenols; D013634:Tannins
keywords: (1)H NMR; HPLC/ESI-MS/MS; Oenological tannins; Plant polyphenols; Quercus robur; α-Glucosidase inhibition