Effects of (-)-epigallocatechin 3-O-(3-O-methyl) gallate (EGCG3″Me)- phospholipids complex on pancreatic α-amylase and lipase activities

(-)-Epigallocatechin 3-O-(3-O-methyl) gallate (EGCG3″Me) has exhibited various biological activities in oolong tea; however, its absorption is poor. In this study, the role of phospholipids on the digestive enzymes inhibitory effect of EGCG3″Me was investigated. EGCG3″ was purified from oolong tea and used to prepare EGCG3″Me-phospholipids complex (EPC). The results showed that EPC exhibited relatively higher stability than EGCG3″Me in mimicked digestion conditions, and the presence of phospholipids increased the transepithelial transport of EGCG3″Me. The half inhibitory concentration (IC50) values of EGCG3″Me and EPC for α-amylase were 0.54 and 1.49 mg/mL, respectively, while the values were 1.14 and 1.69 mg/mL, respectively, for lipase. Lineweaver-Burk double reciprocal plots indicated the inhibitory types of EPC were competitive for α-amylase, whereas it was noncompetitive for lipase. Since phospholipids could improve the bioavailability of tea polyphenols, our investigation may be useful in manufacturing functional foods with increased absorption, containing high content of tea polyphenols. Practical applications The findings suggest the potential of phospholipids for the promotion of the inhibitory effect of EGCG3″Me on digestive enzymes. Although the inhibitory effect of EGCG3″Me on a-amylase and lipase was better than EGCG3″Me-phospholipids complex (EPC), EPC exhibited better stability and permeability. For good bioavailability, tea polyphenols should have a balance between hydrophilicity and lipophilicity, and the complex we prepared may be used for manufacturing functional foods that support improved tea polyphenols absorption.