Development Of Specific Modification Methods For Catechins And Structure And Antioxidant Activity Relationship Investigation

Catechins are one kind of important bioactive flavone compounds, which are widely distributed in plants. The physiological functions of catechins include strong antioxidant activity, significant reduction capacity in cardiovascular diseases and cancers, anti-inflammatory activity, and protective effect on nerve and liver. The low bioavailability and oxidative degradation of catechins greatly limit their applications in food, pharmaceutical and cosmetic industries. It has been demonstrated that their biological activities and physicochemical properties can attributed to the hydroxyls in the molecules. Therefore, it is necessary to systematically evaluate the specific role of each hydroxyl group of catechins in their activities, which requires a systematic exploration of reactivity profile of hydroxyl groups of the molecules. So far, there are three major methods to modify catechins i.e. acylation, glycosylation and methylation.In this study, selective acylation and acetalization of the hydroxyls of (+)-catechin were achieved under mild conditions. Orthogonal disassembly of the Cbz and THP groups were also realized. Then the ABTS antioxidant activities of the modified catechins were determined and the structure and activity relationship was established accordingly. The main research contents of this paper are presented as follows:(1) Development of reasonable reaction route to synthesize5compounds of acylated (+)-catechins.(2) Development of reasonable reaction route to synthesize5compounds of methylated (+)-catechins.(3) Establishment of the structure and activity relationship of the modified (+)-catechins.