[Chemical constituents of Knoxia valerianoides].

To study the chemical constituents of Knoxia valerianoides Thorel et Pitard. Chromatographic methods were used for the isolation and purification. Structures were elucidated on the basis of chemical analysis and spectroscopic data. Three anthraguinones were isolated from K. valerianoides and identified as 1, 3, 5-trihydroxy-2-methyl-6-methoxyl-anthraguinone (kaoxiadin, I), 1, 3, 6-trihydroxy-5-ethoxylmethyl-anthraguinone (II) and 1, 3-dihydroxy-2-methylanthraguinone (rubiadin, III). Compound II is a new anthraguinone constituent.