RESUMO
Objective: To isolate and identify the phenolic constituents with anti-oxidant and anti-α-glucosidase activities from the methanol extract in the twigs of Acer rubrum. Methods: The twigs of A. rubrum were extracted by methanol then partitioned by system solvents with different polarity. The ethyl acetate extract was separated on silica gel, Sephadex LH-20, ODS columns, and by semi-preparative HPLC. The isolated compounds were identified by physicochemical properties and spectral analyses. The DPPH free radical scavenging and anti-α-glucosidase activities of the compounds were also evaluated. Results: Ten phenolic compounds were isolated and purified from the twigs of A. rubrum and were identified as catechin (1), epicatechin (2), epicatechin-3-O-gallate (3), quercetin-3-O-α-L-rhamnoside (4), quercetin-3-O-3″-galloyl-rhamnoside (5), quercetin-3-O-2″-galloyl-rhamnoside (6), phloridzin (7), ginnalin A (8), ginnalin B (9), and ginnalin C (10). Conclusion: Compounds 3 and 5-7 are isolated from the twigs of A. rubrum for the first time. Compound 7 is the only one chalcone isolated from the plants in Aceraceae for the first time. All of the compounds show the good anti-oxidant activities. Compounds 3 and 8 show the strong anti-α-glucosidase activities.