Inhibitor of protein phosphatase 2C (PP2C), selective over PP1, PP2A and PP2B in vitro. Also inhibits mitogen-activated protein kinase phosphatase-1 (MKP-1) (IC50 = 10 μM). Plant alkaloid that exhibits anti-inflammatory and antioxidant activity. Blocks cell cycle in the G1 phase; inhibits cell growth in human prostate carcinoma cells.