Department of Biochemistry, Faculty of Medicine, Chiang Mai University, 110 Intravaroros Road, Sripoom, Muang, Chiang Mai 50200, Thailand.
Food Funct. 2020 Feb 26;11(2):1585-1598. doi: 10.1039/c9fo02820j.
Benign prostatic hyperplasia (BPH) is a common chronic disease in aging men. The present study aimed to identify the active fraction of a purple rice extract and determine its anti-prostatic hyperplasia effect in a testosterone implanted rat model. The hexane insoluble fraction (HIF) which mainly contains hydrophilic phytochemicals from the purple rice crude ethanolic extract was defined as the active fraction, due to a potent effect on the downregulation of androgen receptor (AR) expression in malignant prostate cells, in addition to low toxicity for normal fibroblast cells. To induce BPH, subcutaneous implanting of a testosterone containing tube was performed in the castrated rats. Oral administration of HIF of at least 0.1 g kg-1 retarded prostate enlargement and improved histological changes induced by testosterone, without any effects on the serum testosterone levels. A lower proliferating cell nuclear antigen (PCNA) labelling index and the downregulated expression of AR, cyclinD1, and fatty acid synthase were clearly observed in the prostates of HIF-fed rats. Additionally, the mRNA levels of inflammation-related cytokines and enzymes in the prostate tissues significantly decreased after HIF treatment. Taken together, these findings demonstrate molecular mechanisms underlying the potential protective effects of the purple rice active fraction against testosterone-induced BPH in rats.
良性前列腺增生症（BPH）是老年男性常见的慢性疾病。本研究旨在鉴定紫米提取物的活性部位，并确定其在睾酮植入大鼠模型中的抗前列腺增生作用。由于对恶性前列腺细胞中雄激素受体（AR）表达的下调具有很强的作用，并且对正常成纤维细胞的毒性较低，因此将紫米粗醇提物中的亲脂性植物化学物质主要包含的正己烷不溶部分（HIF）定义为活性部位。为了诱导 BPH，在去势大鼠中皮下植入含有睾酮的管。HIF 的口服给药（至少 0.1 g kg-1）可延迟前列腺增大并改善由睾酮引起的组织学变化，而对血清睾酮水平没有任何影响。在 HIF 喂养的大鼠前列腺中，增殖细胞核抗原（PCNA）标记指数降低，AR、细胞周期蛋白 D1 和脂肪酸合酶的表达下调。此外，前列腺组织中炎症相关细胞因子和酶的 mRNA 水平在 HIF 处理后显著降低。总之，这些发现表明紫米活性部位对大鼠睾酮诱导的 BPH 的潜在保护作用的分子机制。
