Wogonin prevents glucocorticoid-induced thymocyte apoptosis without diminishing its anti-inflammatory action

The effect of wogonin, a flavone highly purified from the roots of Scutellaria baicalensis, on apoptotic cell death was re-evaluated in rat thymocytes. This flavone inhibited glucocorticoid-induced apoptotic changes such as DNA fragmentation, phosphatidylserine translocation, and nuclear condensation in rat thymocytes. Similar inhibition was also observed in apoptosis induced by other inducers such as etoposide. No significant changes of these apoptotic features were observed in rat thymocytes treated with wogonin alone, suggesting that this flavone protects against glucocorticoid-mediated immunosuppression caused by thymocyte apoptosis. Wogonin was reported to possess anti-inflammatory action in some previous studies, but this flavone had no effect on carrageenan-induced paw edema in this study. The simultaneous treatment of wogonin and glucocorticoid neither enhanced nor reduced the anti-inflammatory effect of glucocorticoid. These results indicate that wogonin is likely to prevent the immunosuppression of glucocorticoid without diminishing its drug efficacy as an anti-inflammatory agent.