LAUSR

Background/Objective Stagnant blood (oketsu in Japanese) is considered a severe pathological condition in traditional Chinese and Japanese medicine. Kummerowia striata is known as a weed in Japan; however, in traditional Chinese medicines, it is used for detoxification and for treating colds, fevers, and bruises. To the best of our knowledge, there is no record of this plant, or its parts, being used as an anti-blood stasis agent. Herein, we demonstrated the effect of the 35% ethanol extract (KS) of the aerial part of K. striata on stagnant blood flow (BF) in the peripheral circulation using an in vivo assay. Methods Hen-egg white lysozyme (HEL) was injected into the tail vein of mice to induce stagnant BF, the pathology of which is similar to that of oketsu; then, the changes in BF were observed. Results The oral administration of KS (200 mg/kg) significantly improved HEL-induced BF decrease, suggesting that KS can improve blood stasis. Bioassay-guided fractionation of KS resulted in the isolation of 14 flavone and flavonol derivatives. As apigenin (1) and luteolin (2) reportedly have activity in this assay, here, the effects of isovitexin (3), vitexin (5), rhoifolin (12), and vicenin-1 (14) were examined. Compounds 5, 12, and 14 (20 µmol/kg) more effectively inhibited HEL-induced stagnant BF than 1, which was used as a positive control. Conclusion The aerial part of K. striata could be useful in the discovery of new leads for the prevention of stagnant blood syndrome.