99877-82-4Relevant academic research and scientific papers
Gallotannins and Tannic Acid: First Chemical Syntheses and in Vitro Inhibitory Activity on Alzheimer's Amyloid β-Peptide Aggregation
Sylla, Tahiri,Pouységu, Laurent,Dacosta, Grégory,Deffieux, Denis,Monti, Jean-Pierre,Quideau, Stéphane
supporting information, p. 8217 - 8221 (2015/07/07)
The screening of natural products in the search for new lead compounds against Alzheimer's disease has unveiled several plant polyphenols that are capable of inhibiting the formation of toxic β-amyloid fibrils. Gallic acid based gallotannins are among these polyphenols, but their antifibrillogenic activity has thus far been examined using "tannic acid", a commercial mixture of gallotannins and other galloylated glucopyranoses. The first total syntheses of two true gallotannins, a hexagalloylglucopyranose and a decagalloylated compound whose structure is commonly used to depict "tannic acid", are now described. These depsidic gallotannins and simpler galloylated glucose derivatives all inhibit amyloid β-peptide (Aβ) aggregation invitro, and monogalloylated α-glucogallin and a natural β-hexagalloylglucose are shown to be the strongest inhibitors.
Gallotannin biosynthesis: Purification of β-glucogallin: 1,2,3,4,6-pentagalloyl-β-d-glucose galloyltransferase from sumac leaves in honour of professor G. H. Neil towers 75th birthday
Niemetz, Ruth,Gross, Georg G.
, p. 327 - 332 (2007/10/03)
An enzyme from leaves of staghorn sumac (Rhus typhina) that catalysed the galloylation of 1,2,3,4,6penta-O-galloyl-β-D-glucose to the gallotannin, 3-O-digalloyl-l,2,4,6-tetra-0-galloyl-β-D-glucose, was purified more than 500-fold to apparent homogeneity. β-Glucogallin (l-0-galloyl-β-D-glucopyranose) served as activated acyl donor in this conversion. For the native enzyme, a M, value of 170,000 was determined by gel filtration, while a single polypeptide band of Mr 42,000 was detected by SDS-PAGE. The acyltransferase had pH and temperature optima of 4-4.5 and 25°, respectively, and was most stable between pH 3 and 4.5. Besides the major substrate, pentagalloylglucose, also 1,2,3,6-tetragalloylglucose and hexa- to nona-substituted gallotannins were accepted as minor substrates by this new enzyme for which the systematic name β-glucogallin: l,2,3,4,6-pentagalloyl-β-D-glucose (3-O-galloyl)-galloyltransferase" (EC 2.3.1.-) is proposed.
