[Chemical constituents of roots of Boehmeria nivea]. 
To investigate the chemical constituents from roots of Boehmeria nivea.  The constituents were isolated by repeated column chromatography and preparative liquid chromatography; and their structures were elucidated by chemical properties and spectroscopic analyses.  Seven compounds were isolated and their structures were identified as tormentic acid (1), hederagenin (2), maslinic acid (3), 2alpha-hydroxyursolic acid (4), trans-p-hydroxycinamic acid (5), 2,4,4'-trihydroxychalcone (6), rutin (7).  Compounds 1-6 were obtained from this genus for the first time.