HBX-6, Standardized Cornus officinalis and Psoralea corylifolia L. Extracts, Suppresses Benign Prostate Hyperplasia by Attenuating E2F1 Activation.

BACKGROUND: The aim of this study was to simplify and identify the contents of the herbal formula, HBX-5. This study was carried out to evaluate the therapeutic effects of HBX-6 in a mouse model of benign prostatic hyperplasia (BPH). Based on in vitro, we selected a candidate, reconstituted an experimental agent and investigated the effects on testosterone-induced BPH rats. Cell viability was determined by MTT assay in RWPE-1 and WPMY-1 cells. The expression of androgen receptor (AR) was measured in dihydrotestosterone-stimulated RWPE-1 and WPMY-1 cells. BPH was induced in mice by a subcutaneous injection of testosterone propionate for four weeks. Animals were divided into six groups: Group 1, control mice; Group 2, mice with BPH; Group 3, mice with BPH treated with finasteride; Group 4, mice with BPH treated with 200 mg/kg HBX-5; Group 5, mice with BPH treated with 100 mg/kg HBX-6; and Group 6, mice with BPH treated with 200 mg/kg HBX-6. Changes in prostate weight were measured after treatments, and the thickness of the epithelium was evaluated. The expression levels of proteins associated with prostatic cell proliferation and cell cycle-related proteins were determined. Based on previous reports and in vitro results, we selected Cornus officinalis and Psoralea corylifolia among HBX-5 components and reconstituted the experimental agent, and named it HBX-6. The result represented a new herbal formula, HBX-6 that suppressed the pathological alterations in BPH and showed a marked reduction in proliferation-related protein expression compared to mice with BPH. Our results indicate that HBX-6 has a better therapeutic effect in the BPH murine model than those of HBX-5 and finasteride, suggesting the role of HBX-6 as a new BPH remedial agent.