Water-soluble complexes formed by natural polyphenols and bovine serum albumin: Evidence from gel electrophoresis

The formation of water-soluble complexes from combinations of various polyphenols and bovine serum albumin (BSA) was analyzed by gel electrophoresis. Sodium dodecylsulfate (SDS) and native polyacrylamide gel electrophoretic (PAGE) analyses clearly showed complexes formed from BSA with oenothein B, corilagin, (+)-catechin, procyanidin B3, and gallic acid derivatives; however, it was difficult to distinguish between the complexes containing a single BSA molecule and the BSA molecule itself by using size-exclusion chromatography (SEC). Combining SDS and native PAGE analyses showed instability in the macromolecular complexes formed from pentagalloylglucose (PGG) and BSA. Research also revealed that the oxidation of (-)-epigallocatechin gallate (EGCG) contributed to the formation of more stable macromolecular complexes from EGCG and BSA.