Abstract: Objective To assess the inhibitory effect of the extract of Xanthoceras sorbifolium Bunge flower against benign prostatic hyperplasia (BPH) and explore its possible mechanism. Methods MTT assay was used to examine the effect of the extract of Xanthoceras sorbifolium Bunge flower on proliferation of benign prostatic hyperplasia cells (BPH-1), and cell apoptosis and cell cycle changes following the treatment were analyzed using annexin V/PI double staining and flow cytometry. The protein expression levels of Bcl-2, Bax, caspase-3, PI3K and AKT in the treated cells were detected using Western blotting. A rat model of BPH established by subcutaneous injection of testosterone propionate was treated with the flower extract for 28 days, and pathological changes in the prostate tissue were observed with HE staining. The protein expression levels of Bcl-2, Bax, caspase3 and PI3K/AKT in the prostate tissue were detected with Western blotting. Results Within the concentration range of 125-1000 μg/mL, the flower extract of Xanthoceras sorbifolium Bunge significantly inhibited the proliferation of BPH-1 cells and caused obvious cell cycle arrest at G0/G1 phase; the apoptotic rate of the cells was positively correlated with the concentration of the flower extract (P<0.05). Bcl-2, p-PI3K and p-AKT expression levels were significantly down-regulated and Bax and caspase-3 expression levels were significantly increased in the cells after treatment with the flowers extract (P<0.05). In the rat models of BPH, the rats treated with the flowers extract at moderate and high doses showed obviously decreased expressions of p-AKT and Bcl-2 and an increased expression of Bax in the prostate tissue; a significantly lowered p-AKT expression was observed in the prostate tissue of rats receiving the low-dose treatment (P<0.05). Conclusion The flower extract of Xanthoceras sorbifolium Bunge has a inhibitory effect on BPH both in vitro and in rats, suggesting its potential value in the development of medicinal plant preparations for treatment of BPH.

Key words: flower extract of Xanthoceras sorbifolium Bunge; cell apoptosis; benign prostatic hyperplasia; Bcl-2/Bax/caspase3