Effect of silybin on phalloidin-actin interactions in vitro

The possible antagonism between silybin and phalloidin an F-actin has been examined in vitro. Phalloidin protects F-actin against denaturation by potassium iodine, cytochalasin B, DNase and pronase. Silybin does not counteract the effect of phalloidin on F-actin. However, silybin alone slowed the rate of polymerization of actin, but this effect was moderate and obtained with very high concentrations. These results indicate that the site of action in vitro of silybin is not actin.