Modified Plant Extract Could Rival Viagra

Epimedium brevicornumPlant extracts have traditionally been used as aphrodisiacs and a recent report describes the synthesis of a modified natural product that could be as effective as sildenafil (Viagra®) for treating erectile dysfunction. Icariin, a component of Epimedium brevicornum (also known as horny goat weed) was found to inhibit phosphodiestersae-5 (PDE5), but with an IC50 value almost 100-fold greater than that of sildenafil.
The researchers then modified the structure of icariin to produce compound 5 which was essentially equipotent with sildenafil as an inhibitor of PDE5. Since compound 5 is more selective for PDE5 than sildenafil, which also inhibits phosphodiesterase-6 (PDE6) and cyclic adenosine monophosphate-phosphodiesterase (cAMP-PDE), compound 5 has the potential to cause fewer side effects than sildenafil.