iEquol an isoflavonoid: potential for improved prostate health, <it>in vitro </it>and <it>in vivo </it>evidence

• Main Authors: Hamaker Amy N (Author), Bu Lihong (Author), Blake Crystal (Author), Lund Trent D (Author), Lephart Edwin D (Author)
• Format: Book
• Published: BMC, 2011-01-01T00:00:00Z.
• Subjects: article
• Online Access: Connect to this object online.

Summary

<p>Abstract</p> <p>Background</p> <p>To determine: <it>in vitro </it>binding affinity of equol for 5alpha-dihydrotestosterone (5alpha-DHT), <it>in vitro </it>effects of equol treatment in human prostate cancer (LNCap) cells, and <it>in vivo </it>effects of equol on rat prostate weight and circulating levels of sex steroid hormones.</p> <p>Methods</p> <p>First, <it>in vitro </it>equol binding affinity for 5alpha-DHT was determined using 14C5alpha-DHT combined with cold 5alpha-DHT (3.0 nM in all samples). These steroids were incubated with increasing concentrations of equol (0-2,000 nM) and analyzed by Sephadex LH-20 column chromatography. 14C5alpha-DHT peak/profiles were determined by scintillation counting of column fractions. Using the 14C5alpha-DHT peak (0 nM equol) as a reference standard, a binding curve was generated by quantifying shifts in the 14C5alpha-DHT peaks as equol concentrations increased. Second, equol's <it>in vitro </it>effects on LNCap cells were determined by culturing cells (48 hours) in the presence of increasing concentrations of dimethyl sulfoxide (DMSO) (vehicle-control), 5alpha-DHT, equol or 5alpha-DHT+equol. Following culture, prostate specific antigen (PSA) levels were quantified via ELISA. Finally, the <it>in vivo </it>effects of equol were tested in sixteen male Long-Evans rats fed a low isoflavone diet. From 190-215 days, animals received 0.1cc s.c. injections of either DMSO-control vehicle (n = 8) or 1.0 mg/kg (body weight) of equol (in DMSO) (n = 8). At 215 days, body and prostate weights were recorded, trunk blood was collected and serum assayed for luteinizing hormone (LH), 5alpha-DHT, testosterone and 17beta-estradiol levels.</p> <p>Results</p> <p>Maximum and half maximal equol binding to 5alpha-DHT occurred at approximately 100 nM and 4.8 nM respectively. LNCap cells cultured in the presence of 5alpha-DHT significantly increased PSA levels. However, in the presence of 5alpha-DHT+equol, equol blocked the significant increases in PSA levels from LNCap cells. <it>In vivo </it>equol treatment significantly decreased rat prostate weights and serum 5alpha-DHT levels but did not alter LH, testosterone, and estradiol levels.</p> <p>Conclusions</p> <p>Equol administration appears to have potential beneficial effects for prostate health and other 5alpha-DHT mediated disorders. Equol administration: reduces PSA levels from LNCap cells under 5alpha-DHT stimulation, decreases rat prostate size, decreases serum 5alpha-DHT levels and androgen hormone action, while not altering other circulating sex steroids or LH levels.</p>

Item Description

10.1186/1477-7827-9-4
1477-7827