17β-hydroxy Wortmannin is an analog of wortmannin. It irreversibly binds phosphoinositide 3-kinase (PI3K) and potently blocks fMLP-stimulated respiratory burst in neutrophils (IC50 = 5 nM). 17β-hydroxy Wortmannin inhibits recombinant PI3K and mTOR (IC50 = 2.7 and 193 nM, respectively) and prevents the growth of LNCap prostate cancer cells (IC50 = 1.46 μM). The 17-hydroxyl group has been used to further modify this compound, e.g., by pegylation and conjugation with rapamycin.