Back in 2006, scientists found evidence that high doses of capsaicin could kill prostate cancer cells in mice while leaving healthy cells unharmed, but humans would have to eat huge amounts of peppers each week to get anywhere near the same dose. A better option would be to turn the compound into a concentrated drug, but until now no one's understood exactly how it brings about cell death.
Now scientists in India have shown for the first time how capsaicin binds to a cancer cell and triggers changes within it, which is the first step towards harnessing the compound's effect in medication.
The researchers from the Indian Institute of Technology Madras were able to detect how the compound interacts with cell membranes by monitoring its natural fluorescence. They found that the capsaicin binds to the surface of a cancer cell, and then lodges itself into the cell's membrane.
The presence of the compound begins to trigger chemical changes in the membrane, and if you add enough of it, it actually causes the membranes to come apart, they found.
The team still doesn't quite understand the molecular pathway causing this reaction, but further research could help to unlock ways to harness this effect in cancer treatments.
We're obviously a very long way off being able to use capsaicin therapeutically, but the exciting part about the compound is that it doesn't seem to affect healthy cells, and many humans can already safely tolerate it.
The next step will be to work out exactly what's going on inside the cell membrane, and also how this process happens inside the human body. Then the challenge will be to figure out the best way to trigger this effect.
The original research in mice conducted back in 2006 also didn't show that capsaicin could stop prostate cancer, it simply slowed the growth of tumours by about 80 percent, which is good, but it also suggests that the compound will need to be combined with another type of cancer-fighting molecule if it's put into a drug.
So don't head out and stock up on habañera peppers just yet (honestly, don't, they're going to set your mouth on fire) because the research is still very premature. But this is promising lead on a new compound that could help in the fight against cancer, which is something we very much need.
The results have been published in The Journal of Physical Chemistry B.