Objective
Herbal medicine is an important therapeutic option for benign prostatic hyperplasia (BPH), a common disease in older men that can seriously affect their quality of life. Currently, it is crucial to develop agents with strong efficacy and few side effects. Herein we investigated the effects of the extract of Rauwolfia vomitoria, a shrub grown in West Africa, on BPH.
Methods
Rats with testosterone-induced BPH were treated with R. vomitoria. Prostates were histologically analyzed by hematoxylin and eosin staining. Proliferation index and the expression levels of androgen receptor and its associated proteins were quantified through immunohistochemistry and immunoblotting. Androgen receptor target genes were examined by quantitative real-time polymerase chain reaction. The sperm count and body weight of rats were also measured.
Results
The oral administration of R. vomitoria extract significantly reduced the prostate weight and prostate weight index in BPH rats, supported by the decreased thickness of the prostate epithelial layer and increased lumen size. Similar effects were observed in the BPH rats treated with the reference drug, finasteride. R. vomitoria extract significantly reduced the testosterone-induced proliferation markers, including proliferating cell nuclear antigen and cyclin D1, in the prostate glands of BPH rats; it also reduced levels of androgen receptor, its associated protein steroid 5α-reductase 1 and its downstream target genes (FK506-binding protein 5 and matrix metalloproteinase 2). Notably, compared with the finasteride group, R. vomitoria extract did not significantly reduce sperm count. 
Conclusion
R. vomitoria suppresses testosterone-induced BPH development. Due to its milder side effects, R. vomitoria could be a promising therapeutic agent for BPH.

Key words: Benign prostatic hyperplasia, Rat model, Herbal extract, Androgen receptor, Rauwolfia vomitoria