Hoodia acts not only for weight loss but also as an aphrodisiac:
http://hoodiagordoniiguide.com/how-does-hoodia-work-for-weight-loss.htm
http://fastandslim.blogspot.co.at/2008/07/does-hoodia-have-aphrodisiac.html
Hoodia gordonii and Sceletium tortuosum, both from South Africa:
It is believed that Hoodia works by acting as an agonist on the melanocortin-4- receptor, which suppresses fever, hunger and feeling of satiety and development of libido.
A new synthetic melanocortin-4- agonist is getting famous as the allegedly first real aphrodisiac: Bremelanotide (PT-141)
It doesn't act like viagra and similar medications, but through stimulation of sexual desire in the brain.
The active compound in Hoodia is P57, an oxypregnane steroidal glycoside and other trirhabinosides.
Much attention has been focused in the patent literature on melanocortin agonists and their use in treating body weight and sexual disorders [Andersson et al. Exp. Opin. Ther. Patents 2001, 11, 1583 1592]. The first reported non-peptidicmelanocortin agonist is shown below. It was isolated from a plant extract from the genus Trichocaulon or Hoodia [WO 98/46243, Quandrant Holdings].