## 4 Discussion  
BPH is one of the most common urological diseases of the elderly population [19]. Recently, its incidence has rapidly increased due to the aging of the population, and interest in the use of natural products is increasing to overcome the various side effects of the drugs to treat BPH [20]. Therefore, we prepared BenPros by mixing plant-derived extracts of green tea extract, soybean extract, and camellia japonica oil, which are known to have anti-inflammatory and prostate protective effects [21; 22; 23], and evaluated its BPH protective effect. DHT and AR are considered to be key factors contributing to the development of BPH [24]. Testosterone is converted to DHT by 5 aR and binds to AR. DHT binding to AR has been reported to increase the expression level of PSA, one of the representative androgen-responsive genes expressed in the prostate [25]. Moreover, AR regulates BPH development through inflammation with macrophage infiltration [26]. DHT-AR complex enhanced macrophage migration and macrophage-mediated proliferation of prostate epithelial cells and stromal cells [27; 28; 29]. Such proliferation of prostate epithelial cells and stromal cells results from pro-inflammatory cytokines secreted by macrophages in prostate tissue [30]. The activation of macrophages produces cytokines including TNF-\(\alpha\) and IL-6 under BPH conditions and contributes to prostate hypertrophy and epithelial cell growth [31]. In addition, PSA is a protein that is specifically expressed in the prostate. Since PSA protein is known to be overexpressed in TP-induced BPH rodents [32], its regulation also acts as an important marker for improvement of BPH. Therefore, regulating the expression of AR and inhibiting macrophage inflammation is one of the important therapeutic strategies for BPH. In this study, BenPros showed the effects of reducing the levels of 5 aR, AR, and PSA increased by testosterone in LNCaP-LN3 cells, and inhibited IL-6 and TNF-\(\alpha\) production in LPS-stimulated macrophage cells. Moreover, in the TP-induced BPH model, the serum levels of DHT and PSA as well as the protein expression of PSA in prostate tissue were also reduced. In histological analysis, BenPros significantly reduced prostate hypertrophy and histopathological changes in TP-induced BPH rats. These results indicate that BenPros can inhibit the progression and development of BPH by reducing DHT-AR complex and macrophage inflammation. Pro-inflammatory cytokines induce the expression of COX-2 [33]. COX-2 is observed in all inflammatory cells of the prostate epithelium and stroma in BPH patients [34]. COX-2 inhibits cell death by increasing the expression of anti-apoptotic proteins, such as Bcl-2 [35]. Moreover, the inhibition of COX-2 can significantly increase apoptosis of prostate cells [36]. The action of COX-2 on proliferative prostate cells can be achieved by directly stimulating Bcl-2 signaling [37]. The Bcl-2 family of proteins, including anti-apoptotic protein Bcl-2 and pro-apoptotic protein Bax, regulated intrinsic apoptosis [38]. Several researchers also reported that increased Bcl-2 expression and Bcl-2/Bax ratio were observed in the BPH [39]. Moreover, relatively low levels of Bcl-2 expression were detected in normal prostate condition, whereas an imbalance of apoptosis signaling was observed in the BPH group [40]. Therefore, the regulation of the balance between Bax and Bcl-2 seems to be an important strategy for the recovery of BPH. In our study, BenPros significantly inhibited the expression of COX-2 and Bcl-2 proteins and reduced the Bcl-2/Bax ratio in the prostates of TP-induced BPH rats. These results suggest that BenPros can ameliorate TP-induced BPH by regulating the expression of COX-2 and triggering apoptotic execution phases by decreasing the Bax/Bcl-2 ratio. Based on the results of preliminary experiments, we assumed that the major active compounds of BenPros were EGCG and daidzein (Supplementary Figure S1). Moreover, oleic acid, which is known to be rich in camellia oil, was also expected to help the action of BenPros.