Damiana (Turnera diffusa Willd.) – a traditionally used aphrodisiac as modern PDE-5 inhibitor

Selective phosphodiesterase-5 (PDE-5) inhibitors like Sildenafil, Tardanafil or Vardenafil are commonly used for the treatment of Erectile Dysfunction (ED). PDE-5 inhibitors are generally not considered as aphrodisiacs because they do not have any direct effect on the libido. However, increased ability to attain an erection may be interpreted as increased sexual arousal by users of these drugs. An aphrodisiac is a substance that increases sexual desire. One link between PDE-5 inhibitors and aphrodisiacs might be the herbal drug Folia Damiana. The leaves of Damiana (Turnera aphrodisiaca) have a long history of traditional use as aphrodisiac in Mexico [1]. Nowadays Damiana products claimed to increase libido and sexual performance are widely marketed, whereas scientific data are scarce: Damiana extracts were shown to stimulate sexual behaviour in rats [2,3]. Our previous investigations showed for the first time, that Damiana leaf preparations influenced PDE-5 activity in vitro [4]. In the present study a crude 60% w/w ethanolic Damiana extract was investigated for its inhibitory activity on PDE-5 in vitro and was further optimised using different purification techniques. In conclusion, PDE-5 inhibition might be a possible mechanism of action of Damiana. An human study on the effects of FB9389 on mild Erectile Dysfunction in male subjects is currently in progress.