Aim: To study the chemical constituents of Knoxia valerianoides Thorel et Pitard.
Methods: Chromatographic methods were used for the isolation and purification. Structures were elucidated on the basis of chemical analysis and spectroscopic data.
Results: 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).
Conclusion: Compound II is a new anthraguinone constituent.