The compounds that give bitter flavour to wild cucurbits - cucumber, pumpkin, melon, watermelon and squash - have the potential to treat cancer and diabetes, finds a research.
These compounds called cucurbitacins protect the wild plants against predators and have the potential to suppress growth of cancer cells.
The fruit and leaves of wild cucurbits have been used in Indian and Chinese medicine for thousands of years, as emetics and purgatives and to treat liver disease.
"You do not eat wild cucumber unless you want to use it as a purgative," said study co-author William Lucas, professor of plant biology at University of California, Davis.
The researchers identified the genes responsible for the intense bitter taste of wild cucumbers.
They employed the latest in DNA sequencing technology to identify the exact changes in DNA associated with bitterness.
They were able to identify nine genes involved in making cucurbitacin and show that the trait can be traced to two transcription factors that switch on these nine genes, in either leaves or the fruit, to produce cucurbitacin.
The new research shows how domestication tweaked cucumber genetics to make the fruit more edible.
The study appeared in the journal Science.