## 1 Introduction  
Benign prostatic hyperplasia (BPH) is the most common urological condition affecting about half of men over the age of 50 years [1]. It is known to be caused by excessive proliferation of prostate epithelial and stromal cells surrounding the urethra [2]. Hypertrophy of the prostate triggers lower urinary tract symptoms such as urgency, urinary frequency, urgency incontinence, and weak stream, and various urination disorders due to urethral stenosis or obstruction due to an increase in prostate size [3].  
The pathogenesis and development of BPH is still unknown, but speculated to be associated with age-related tissue remodeling and hormonal disturbances [4]. In particular, as the concentration of testosterone decreases with aging, the activity of 5\(\alpha\)-reductase (5\(\alpha\)R) is maintained at a high level, resulting in testosterone conversion to active 5\(\alpha\)-dihydrotestosterone (DHT), a more potent androgen [5]. Activated DHT forms a complex with the androgen receptor (AR), thereby increasing the transcriptional activity of androgen-dependent genes and ultimately inducing prostate cell proliferation [6]. Chronic inflammation is also a major factor in BPH progression [7]. Several researchers reported an increase in macrophages infiltration in prostate tissues from BPH patients and murine [8]. The restoration of tissue damage and inflammatory response leads to the induction of abnormal prostate enlargement [9]. Therefore, regulation of the increased 5 aR and inflammatory cytokines is important for the improvement of BPH.  
The two main types of treatment for BPH developed to date include 5\(\alpha\)-reductase blockers (5 aR inhibitors) and \(\alpha\)-1 adrenergic receptor (\(\alpha\)-1 AR) antagonists (also called alpha blockers) [9]. Finasteride inhibits DHT formation by inhibiting 5 aR activity and has a few side effects including orthostatic hypotension and sexual dysfunction [10]. In addition, as alpha-1 AR antagonists are sympathetic blockers, major side effects include syncope, dizziness, and orthostatic hypotension [11]. Therefore, it is imperative to develop a new treatment with fewer side effects that can alleviate the symptoms of BPH. Moreover, saw palmetto has fewer side effects compared to finasteride [12], and is well known as one of the effective alternative medicines for BPH [13]. Particularly in the Republic of Korea, saw palmetto is the most famous functional food for hypertrophy of the prostate. Therefore, we used finasteride and saw palmetto, which are representative therapeutic agents and functional foods that improve BPH, as positive controls in animal experiments, and tried to compare the effects of BenPros with them.  
BenPros is a mixture of green tea extract, soybean extract, and camellia japonica oil. Green tea and its active polyphenols such as catechins are well known to have a protective effect on BPH and prostate cancer [14]. Soybean is also known to have a protective effect on BPH [15], and isoflavenes such as genistein and diadzein, abundantly contained in soybean, have been reported to have excellent effects on BPH [16]. Although Camellia japonica oil has not been reported to have protective efficacy against BPH, it has been reported to have an anti-inflammatory effect by downregulating the expression of inducible nitric oxide synthase and cyclooxygenase-2 (COX-2) genes [17]. As with previous studies, we confirmed that epigallocatechin-3-gallate (EGCG) and diadzein improved BPH-related markers and IL-6 in vitro. Moreover, camellia oil showed the possibility of improving BPH in vivo through preliminary experiments (Supplementary Figure S1). Therefore, we thought that mixing these three extracts could be a way to develop a BPH-improving functional food candidate material that is safe and has excellent efficacy.  
In this study, we hypothesized that this phyto-extract mixture, BenPros, has protective effects on BPH, and investigated to determine its effectiveness in improving BPH in vitro and in an animal model.