RESUMO
<p><b>OBJECTIVE</b>To study the antioxidant constituents from the root of Rubus crataegifolius.</p><p><b>METHOD</b>The constituents isolation and purification from the root of R. crataegifolius was carried by reported column chromatography including silica gel, toyopearl, and their structures were elucidated on the basis of spectral compounds. DPPH method was used to evaluate the free radical scavenging activity of the isolated compounds.</p><p><b>RESULT</b>Nine compounds were isolated from the root of R. crataegifolius, and their structures were identified as follow: euscaphic acid (1), kaempferol-3-O-beta-D-galactopyranoside (2), tormentic acid (3), 2alpha, 19alpha, 24-trihydroxyurs-12-ene-3-oxo-28-acid (4) , 2alpha-hydroxy-oleanolic acid (5), ursolic acid (6), daucosterol (7), beta-sitosterol (8) and polydatin (9). By experiment of antioxidant activity, the result showed compounds 2 and 9 revealed DPPH free radical scavenging rates were 95.60% and 75.23% at the concentration of 50 mg x L(-1).</p><p><b>CONCLUSION</b>Compounds 1-8 were isolated from this plant for the first time, and compounds 2 and 9 showed the significant antioxidant activity.</p>