The Thermal and Enzymatic Taxifolin-Alphitonin Rearrangement

作者:Elsinghorst Paul W*; Cavlar Taner; Mueller Anna; Braune Annett; Blaut Michael; Guetschow Michael
来源:Journal of Natural Products, 2011, 74(10): 2243-2249.
DOI:10.1021/np200639s

摘要

This report describes a detailed investigation of the thermal and enzymatic conversion of taxifolin to alphitonin. Chromatographic separation of the four dihydroquercetin stereoisomers 1-4 in combination with circular dichroism spectroscopy permitted elucidation of the kinetics of this rearrangement and characterization of the different reaction pathways involved. Our findings are corroborated by quantum chemistry calculations that reveal a unique cascade of tautomerization processes leading from taxifolin to alphitonin and also explain the racemization of alphitonin at room temperature. Furthermore, the substrate specificity toward (+)-taxifolin of an enzyme from Eubacterium ramulus catalyzing this intriguing rearrangement is demonstrated.

  • 出版日期2011-10