RESUMO
Objective: To study the non-alkaloid constituents from the stems and leaves of Alstonia mairei. Methods: The chemical constituents were separated and purified by silica gel, ODS, Sephadex LH-20 gel column chromatographies, and preparative HPLC. Their structures were determined by physicochemical properties, spectral data, as well as comparisons with the data in literature. Results: Eighteen compounds were isolated from the petroleum ether fraction of 90% ethanol extract from the stems and leaves of A. mairei, and identified as lupeol (1), 30-oxo-lupeol (2), lupenyl acetate (3), α-amyrin (4), α-amyrenone (5), 23-hydroxyursolic acid (6), β-amyrin (7), β-amyrenone (8), maslinic acid (9), friedelinol (10), friedelin (11), tectochrysin (12), 5,6-dihydroxy-7,4'- dimethoxyflavone (13), 5,3'-dihydroxy-7,4'-dimethoxyflavone (14), 7-hydroxy-7,5,3',4'-trimethoxyflavone (15), 5,7,3',4'- tetramethoxyflavone (16), 5-hydroxy-6,7,8,4-tetramethoxyflavone (17), and 5-hydroxy-6,7,8,3',4'-pentamethoxyflavone (18). Conclusion: All compounds are isolated from A. mairei for the first time. In addition to compound 1, the other compounds are isolated from the plants of Alstonia R. Br. for the first time.