Kahweol is a natural diterpene that is isolated from coffee beans. It increases glutathione S-transferase activity in the gut mucosa of mice and, with the diterpene cafestol, induces glutathione S-transferase expression in rat livers. Kahweol has anti-inflammatory effects in RAW macrophages, inhibiting LPS-induced nitric oxide and prostaglandin E2 production (IC50 = 54 and 23 μM, respectively). Kahweol also is antiangiogenic, blocking the proliferation of endothelial cells (IC50 = 50 μM) and inhibiting endothelial migration, invasion, and tube formation. Kahweol is easily oxidized in the presence of air.
