A mass spectrometry and H-1 NMR study of hypoglycemic and antioxidant principles from a Castanea sativa tannin employed in oenology

作者：Cardullo Nunzio; Muccilli Vera^*; Saletti Rosaria; Giovando Samuele; Tringali Corrado

来源：Food Chemistry, 2018, 268: 585-593.

DOI：10.1016/j.foodchem.2018.06.117

• Tannins
• Castanea sativa
• Hypoglycemic activity
• DPPH
• ORAC
• Mass spectrometry
• H-1 NMR

The ethanol extract of the commercial tannin Tan'Activ C, (from Castanea sativa wood), employed in oenology, was subjected to chromatography on XAD-16 affording fractions X1-X5, evaluated for total phenols content (GAE), antioxidant activity (DPPH, ORAC), and hypoglycemic activity (alpha-glucosidase inhibition). Fraction X3 showed GAE, radical scavenging activity, and alpha-glucosidase inhibition higher than those of the Castanea sativa extract, and was subjected to chromatography on Sephadex LH-20 to obtain fractions Sl-S7, analyzed by HPLC/ESI-MS/MS and H-1 NMR to identify the main active constituents. In fractions with higher antioxidant activity, gallic acid (4), grandinin (5), valoneic acid dilactone (9), 1,2,3-tri-O-galloyl-beta-glucose (14), 3,4,6 tri-O-galloyl-beta-glucose (15) and galloyl derivative of valoneic acid dilactone (21) were identified as the major constituents. The highest hypoglycemic activity was found in fractions S6 and especially S7; the major constituents of these fractions are valoneic acid dilactone (9), three tetragalloyl glucose isomers (16-18) and 1,2,3,4,6-penta-O-galloyl-beta-glucose (23), previously reported as alpha-glucosidase inhibitors.

• 出版日期2018-12-1