Abstract Inactivation of the androgen receptor (AR) through androgen ablation and treatment with antiandrogens is a major goal in the therapy for prostate hyperplasia and prostate cancer. Bioactivity-directed fractionation of a selective dichloromethane extract from the stem bark of Pygeum africanum led to the isolation of the antiandrogenic compound atraric acid. Its activity was examined by an androgen receptor responsive reporter gene assay. For ...