199 Archivio Italiano di Urologia e Andrologia 2018; 90, 3 ORIGINAL PAPER Serenoa repens extracts: In vitro study of the 5α-reductase activity in a co-culture model for Benign Prostatic Hyperplasia Daniela Buonocore 1 , Manuela Verri 1 , Laura Cattaneo 1 , Sara Arnica 1 , Michele Ghitti 2 , Maurizia Dossena 1 1 University of Pavia, Pavia (Italy), Department of Biology and Biotechnology “L. Spallanzani”; 2 University of Pavia, Pavia (Italy), Department of Earth and Environmental Sciences (DSTA) - Unit of Statistical Analyses (UNISTAT). Objectives. Benign Prostatic Hyperplasia (BPH) is a form of benign tumor that occurs in humans mainly with ageing. It affects more than 50% of over 50 years old males and it is characterized by an increased syn- thesis of dihydrotestosterone (DHT), due to the 5α-reductase activity. The BPH therapeutic approach mainly uses 5α-reduc- tase inhibitors, such as the active compounds present in the extracts deriving from species Serenoa repens. Many lipido- sterolic extracts are available on the market, which are obtained with different solvents, among them ethanol is recog- nized as non-toxic and has less handling risks than hexane. The purpose of the present experimental study was to investi- gate in-vitro the potency of an ethanol extract of S. repens com- paring it with an n-hexane one. Materials and methods. Two different lipido-sterolic extracts of S. repens have been tested: ethanol extract and n-hexane extract, two batches for each one. The inhibitory action of the extract was evaluated estimating in-vitro the activity of enzyme 5α-reductase type I (5α-RI), which was mainly active under the experimental condition of pH 7.5. DHT amount, synthesized from testosterone (1 μM), was evaluated in a co-culture model of epithelial cells and fibroblasts resulting from prostatic biopsy of a patient with BPH. Results. The analysis of the resulting dose-response curves showed that the entire S. repens extracts inhibited the 5α-RI showing no difference between the two kinds of extract or between the batches. The resulting IC50 values were the follow- ing: 8.809 (95% CI = 5.133-15.56) and 9.464 (95% CI = 5.094- 18.27) for ethanol extracts; 11.08 (95% CI = 6.389-19.98) and 12.72 (95% CI = 7.758-21.53) for n-hexane extracts. Conclusions. The potency of ethanol extracts of S. repens was comparable with the one of n-hexane extracts. KEY WORDS: Benign Prostatic Hyperplasia; Dihydrotestosterone; Ethanol extracts; In-vitro study; 5α-reductase; Serenoa repens. Submitted 7 May 2018; Accepted 12 July 2018 Summary No conflict of interest declared. action of enzyme 5α-reductase, which leads to an increase of the prostate size and causes various disorders, especially in the lower urinary tract (1, 2). The approach for the treatment and therapy of BPH is mainly based on the use of inhibitors of 5α-reductase enzyme, in particu- lar natural inhibitors, such as the active compounds present in the alcoholic extracts deriving from species Serenoa repens, a typical palm common in the Subtropical sandy soils and in the southern coasts of the United States. Although the sure mechanism of action of S. repens is not yet fully understood, numerous mecha- nisms have been proposed (3) and the presence of spe- cific fatty acids (saturated and unsaturated fatty acids) and phytosterols in its alcoholic extracts confers upon S. repens an anti-inflammatory and above all antiprolifera- tive action on prostatic tissue (4). Both a systematic Cochrane review of the literature (5) and a meta-analysis (6) assessed the safety profile and the clinical efficacy of S. repens in the treatment of symptoms in patients with BPH. These studies have shown an improvement of uri- nary tract disorders, with a mild to moderate effect and, therefore, a lack of therapeutic equivalence between S. repens extracts of different brands and between extracts of a single brand, but belonging to different manufactur- ing batches (5, 6). Many lipido-sterolic extracts are com- mercially available, which were obtained with different solvents, among them ethanol is recognized as non-toxic and it has less handling risks than hexane (7, 8). The purpose of the present experimental study was to inves- tigate in-vitro the potency of an ethanol extract of S. repens comparing it with an n-hexane one. In particular, the activity of enzyme 5α-reductase was estimated in- vitro concerning the inhibitory action of the extracts, using co-cultures of epithelial cells and fibroblasts result- ing from prostatic biopsy of a patient with BPH. MATERIALS AND METHODS Samples Two extracts, belonging to commercial brands SABA ® (Lampugnani Farmaceutici) and PERMIXON ® (Pierre Fabre Pharma), supplied with marketing authorization in DOI: 10.4081/aiua.2018.3.199 INTRODUCTION Benign Prostatic Hyperplasia (BPH) is a form of benign tumor that occurs in humans mainly with ageing. In fact, it affects more than 50% of over 50 years old males, with an incidence rate directly proportional to age (1). It is characterized by an increased synthesis of dihydrotestos- terone (DHT) starting from testosterone, due to the