Wilforlide A is a bioactive triterpene, which occurs in Tripterygium wilfordii. T. Wilfordii is used in Chinese traditional medicine for treating immune-related inflammatory diseases.
Withaferin A is a cell-permeable steroidal lactone from a medicinal plant Withania somnifera, a plant known in traditional Indian medicine.
Wortmannin is a steroid metabolite of the fungus Talaromyces wortmannii. It is a specific covalent inhibitor of phosphoinositide 3-kinases.