Benign prostatic hyperplasia (BPH) is characterized by the nonmalignant hypertrophy of epithelial and stromal cells. Although the pathogenesis of BPH is not completely elucidated, it is associated with androgens, and includes increased proliferation and decreased apoptosis of cells in the prostate gland. This study investigates the effects of a 99.9% ethanol extract of Zingiber officinale Roscoe (ZOET) on the BPH-1 cell line and the testosterone propionate-induced BPH rat model. Z. officinale Roscoe was extracted with 99.9% ethanol, giving a final yield of 5%. The amounts of polyphenols and flavonoids in ZOET were determined to be 161.58±6.00 mg gallic acid equivalent/g and 71.47±1.85 mg catechin equivalent/g, respectively. Antioxidant activity was assessed using the 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) assay (57.15±0.62%) and the α,α-diphenyl-β-picrylhydrazyl assay (58.46±1.60%). Exposure to ZOET significantly inhibited proliferation of the benign prostatic hyperplasia epithelial cell line, BPH-1. In vivo studies were performed with seven weeks male SD rats divided into four groups: Control, BPH, ZOET 50 mg/kg, and ZOET 150 mg/kg. BPH was induced via subcutaneous injections of testosterone propionate (TP) (3 mg/kg), daily for 4 weeks after castration. ZOET was administered daily by oral gavage, simultaneously with the TP injections. Administration of ZOET 150 mg/kg in the BPH rat model significantly reduced the prostate ratio and 5α-reductase 2 levels of prostate by 16.77% and 24.59%, respectively. DHT levels in serum were also reduced by 30.97%. The Bax/Bcl-2 ratio in prostate was increased 1.6-fold. These results indicate that the inhibitory effects of ZOET on BPH are exerted by regulation of androgens and apoptosis.

Keywords: benign prostatic hyperplasia, Zingiber officinale Roscoe, dihydrotestosterone, 5α-reductase 2, apoptosis