A group of Brazilian scientists was investigating a group of similar molecules as a remedy against Chagas disease, a parasitic illness that can lead to heart failure, when they happened on a discovery.

The substances were not effective against Chagas disease, but some of the rats used in the study did display potent erections.

After studying the phenomenon further, the team from Unifran (Franca University, in the state of São Paulo), concluded that one of the substances, (-)-cubebin (pronounced "minus cubebin") could be used to combat erectile dysfunction in humans, with advantages over other products currently on the market, such as Viagra.

According to the coordinator of the study, the pharmacist Márcio Luis Andrade e Silva, the team recently obtained the patent for this use of the molecule in the United States, and are currently negotiating more detailed investigations with representatives from the pharmaceutical industry.

"We might have excellent news shortly, but negotiations remain confidential," he says.

The molecule, as its name suggests, was obtained from cubeb, also known as Java pepper (Piper cubeba), a plant native to Indonesia, and traditionally used as a spice or for medicinal purposes.

Andrade e Silva says the team made changes to the molecular structure of cubeb derivatives, testing them against diseases such as schistosomiasis, or as an anti-inflammatory.

After observing the curious effect on rats, the team began to conduct more detailed tests, analyzing the corpus cavernosum of the animals' penises.

This is the part of the penis which, upon receiving an increased flow of blood, is responsible for maintaining the erection.

"We compared (-)-cubebin with the main ingredient in Viagra and we observed that it is 50% more powerful," says Andrade e Silva. Simply put, the plant derivative fills the penis with blood in a more efficient manner, ensuring it is more turgid ("full").

The studies also showed that the substance inhibits the action of an enzyme, phosphodiesterase-5, which keeps the penis flaccid. Current remedies available on the market also inhibit this enzyme in a similar manner.

If the substance is to become a new product, more tests on animals will be necessary, as well as at least three separate sets of clinical trials with human patients, which is likely to require several years of research.