Mitodepressive, clastogenic and biochemical effects of (+)-usnic acid in mice

Mice were treated orally with aqueous suspensions of (+)-usnic acid in a single dose of either 100 or 200 mg/kg. The effects on femur cells and proteins and on nucleic acids of liver cells were studied 24-72 h after treatment. (+)-Usnic acid was found to affect the proliferation of polychromatic erythrocytes possibly by interference with RNA biosynthesis. The slight increase in the micronucleated polychromatic erythrocytes without affecting DNA synthesis suggests an effect of usnic acid on spindle apparatus.