Catechin Glucosides: Occurrence, Synthesis, and Stability

Catechins are flavonoids with suggested health benefits, but are unstable during storage, processing and, after ingestion, during gut transit. We hypothesized that catechin glucosides, which occur in various plants, could be more stable than unsubstituted catechin, and additionally be deglucosylated in the gut and so act to deliver catechin in a form able to be absorbed. (+)-Catechin O-glucosides from various sources have been used in the course of this investigation. (+)-Catechin 3′-O-β-d-glucopyranoside (C3′G), (+)-catechin 5-O-β-d-glucopyranoside (C5G), and (+)-catechin 3-O-β-d-glucopyranoside (C3G) were chemically synthesized. (+)-Catechin 4′-O-β-d-glucopyranoside (C4′G) and (+)-catechin 7-O-β-d-glucopyranoside (C7G) were prepared enzymically using preparations from lentil and barley. In general, but with some exceptions, the (+)-catechin glucosides were more stable between pH 4 and 8 than (+)-catechin, with C3′G exhibiting greatest stability. The intestinal metabolism of (+)-catechin and all (+)-cate...