Carnosol

Carnosol is a potent Ribosomal S6 Kinase (RSK2) inhibitor that could be useful for treating gastric cancer, with an IC₅₀ of ~5.5 μM^[1]. Carnosol, a Nrf2 activator, increases the nuclear levels of Nrf2 and can promote the expression of heme oxygenase 1 (HMOX1)^[2][3]. IC50 & Target:IC50: 5.5 μM (RSK2)^[1]. In Vitro: It is showed that carnosol has no cytotoxic effects on GES1 cells and 10 μM carnosol strongly suppresses RSK2 activity, but has little effect on any other kinase. Carnosol exerts strong dose-dependent inhibitory effects against RSK2 autophosphorylation and phosphorylation of its substrate ATF1^[1]. In Vivo: Results indicate that Carnosol significantly decreaseS the volume and weight of gastric tumors relative to the vehicle-treated group. Additionally, mice tolerate treatment with carnosol without significant loss of body weight similar to the vehicle-treated group. The phosphorylation of CREB, a direct downstream protein of RSK2, Is strongly inhibited in the carnosol-treated group but the expression of total CREB is relatively unchanged^[1].