RESUMO
Objective: To study the chemical constituents from the barks of Betula platyphylla. Methods: The chemical constituents were isolated by silica gel column chromatography and HPLC, and its structure were identified by their spectral data and physicochemical properties analysis. Results: A total of 20 compounds were isolated from B. platyphylla, which were identified as 3-oxo-24-methylenecycloartan (1), sitosterone (2), 3β-acetyl oleanolic acid (3), lupeol (4), citrostadienol (5), betulinaldehyde (6), 3β-acetoxyl-11α,12α-epoxy-oleanan-13β,28-olide (7), oleanolic acid (8), erythrodiol (9), 3-hydroxy-1,7-bis(4',4″- dihydroxyphenyl)- heptane (10), β-sitosterol (11), 3β,20-dihydroxylupane (12), 3β-O-caffeoyl-betulin (13), platanic acid (14), 3β,12α-dihydroxyoleanan- 13β,28-olide (15), 30-norlupane-3β,28-diol-20-one (16), betulinic acid (17), betulin (18), 1,7-bis (4',4″-dihydroxyphenyl)-hept- 4-ene-3-one (19), and 5-hydroxy-1,7-bis (4',4″-dihydroxyphenyl)-hept-3-one (20). Conclusion: Compounds 1, 5, 7, 12, 14-16 are isolated from B. platyphylla for the first time, and compounds 1, 5, 7, 14-16 are isolated from betula genus for the first time.