In prostate cancer cells, urolithins (A, B, C, and D) inhibited CYP1B1 activity (a target in prostate cancer chemoprevention) in a dose ranging from 1.15 μM (urolithin A) to 137 μM (urolithin D) whereas higher concentrations were needed for CYP1A1 activity inhibition (12.4–2,907 μM). The gene discussed is CYP1B1; the disease is prostate cancer.