Antiviral anthraquinones from the roots of Knoxia valerianoides

- Three new anthraquinones were isolated from Knoxia valerianoides.
- Other nine known compounds were obtained from K. valerianoides for the first time.
- Their structures were established through interpretation of spectroscopic data.
- The absolute configuration of 1 was confirmed by its optical rotation and CD spectrum.
- Compounds 1 and 4 showed antiviral activity.