Effects of Icariin on erectile function and expression of nitric oxide synthase isoforms in castrated rats
For millions of men, erectile dysfunction is a serious and life changing problem. As men age, testosterone levels decline and estrogen levels increase resulting in diminished sex drive and performance.
During sexual stimulation, nitric oxide release is triggered into penile tissue by the parasympathetic nervous system and by skin cells in the penis. Smooth muscles in the penis are relaxed by the nitric oxide and the specialized tissues of corpus cavernosum and corpus spongiosum are allowed to engorge with blood to achieve erection. Cyclic guanosine monophosphate (cGMP) is responsible for relaxing penile arteries to encourage blood flow to the penis. At the same time, blood is temporarily prohibited from leaving the penis allowing it to stay erect for a period of time. Erectile dysfunction can be treated by increasing the availability of nitric oxide and decreasing the breakdown of cyclic guanosine monophosphate (cGMP).
Many of the common prescription drugs for erectile dysfunction work by inhibiting the degradation of (cGMP). Some natural remedies which are beneficial in treating erectile dysfunction include arginine, yohimbe, and panax ginseng. Arginine is an amino acid used by the body to produce the nitric acid. Yohimbe and panax ginseng are two botanicals which have been used for centuries to enhance sexual performance. Yohimbe functions to prevent the smooth muscle contraction that reduces penile blood flow and decreases erection. Panax Ginseng functions to increase the release of nitric acid in erectile tissue.
A recent study in the Journal of Sex Medicine indicates that oral dosing of Icariin, an active constituent of Horny Goat Weed (Epimedium spp) for 4 weeks is an effective natural remedy for erectile dysfunction. Icariin has been shown to potentially increase the percent of smooth muscle tissue stimulated by nitric oxide and increase the amount of nitric oxide synthase. This means that horny Goat Weed potentially relaxes the smooth muscle fibers of the penis, allowing more blood to flow into the penis resulting in engorgement and erection. Changes in serum testosterone levels were not significant