A Preliminary Investigation of the Enzymatic Inhibition of 5α-Reductase and Growth of Prostatic Carcinoma Cell Line LNCap-FGC by Natural Astaxanthin and Saw Palmetto Lipid ExtractIn Vitro

Inhibition of 5oc-reductase has been reported to decrease the symptoms of benign prostate hyperplasia (BPH) and possibly inhibit or help treat prostate cancer. Saw Palmetto berry lipid extract (SPLE) is reported to inhibit 5a-reductase and decrease the clinical symptoms of BPH. Epidemiologic studies report that carotenoids such as lyco-pene may inhibit prostate cancer. In this investigation the effect of the carotenoid astaxanthin, and SPLE were examined for their effect on 5a-reductase inhibition as well as the growth of prostatic carcinoma cells in vitro.These studies support patent #6,277,417 B1.The results show astaxanthin demonstrated 98% inhibition of 5a-reductase at 300 μg/mL in vitro.Alphastat, the combination of astaxanthin and SPLE, showed a 20% greater inhibition of 5a-reductase than SPLE alone in vitro.A nine day treatment of prostatic carcinoma cells with astaxanthin in vitroproduced a 24% decrease in growth at 0.1 mcg/mL and a 38% decrease at 0.01 mcg/mL. SPLE showed a 34% decrease at 0.1 mcg/mL.Conclusions: Low levels of carotenoid astaxanthin inhibit 5a-reductase and decrease the growth of human prostatic cancer cells in vitro.Astaxanthin added to SPLE shows greater inhibition of 5a-reductase than SPLE alone in vitro.