Three new chromones from the whole plants of and their anti-rotavirus activities.

() is a perennial herb of leguminosae, which increasingly being grown as a forage in China. In our search for original bioactive metabolites from plants, the phytochemical reinvestigation of the was carried out, which led to the isolation of three new (-) and six known (-) chromones. Their structures were confirmed by spectroscopic methods, including extensive 1D and 2D NMR techniques.