The Structural Variation in the Incubation Products of (-)-Epigallocatechin Gallate in Neutral Solution Suggests Its Breakdown Pathways

Three new compounds, in addition to previously reported compounds, were isolated from a product mixture obtained on incubating (-)-epigallocatechin gallate (EGCG) in neutral solution. The products were two monomeric (EGCG-MOx-M3 and EGCG-MOx-M4) and one dimeric (EGCG-MOx-D4) structure involving the flavan skeleton. Possible oxidation-reduction pathways producing drastic changes in the structure of EGCG were presented based on the structures of the breakdown products.