Bitter Medicine: a Boon From Wild Cucumbers

Age old traditional medicines don't always get it right, but once in a while they prove that practitioners were on to something long before western medicine showed up to steal the show. That's how it is in the case of wild cucumbers, where the compounds that can be found in their fruit and leaves have been rediscovered by modern science.

Traditional Indian and Chinese medicine used the exceptionally bitter leaves and fruit of cucumbers and other cucurbits (wild squash, melon, and pumpkins) to induce vomiting and to even treat liver disease.

"You don't eat wild cucumber, unless you want to use it as a purgative," William Lucas, a plant biologist at the University of California, Davis, explained in a recent statement.

That bitter compound was effectively bred out of domestic cucurbits long ago, ensuring that your afternoon salad will remain in your stomach. However, wild species used that intense bitterness to protect themselves from hungry predators.

Past research has found that theses bitter compounds have other medical benefits as well, where they may help fight inflammation and adverse body reactions that lead to things like diabetes and the growth of cancer cells. However, it has been difficult to extensively test for this, as the wild compounds are hard to gather in large quantities.

That's why Lucas and his colleagues at the Chinese Academy of Agricultural Sciences sought to figure out what genetic information produces these bitter compounds. They quickly determine that two genetic traits produced the bitterness in leaves and fruit separately, and we able to taste-test their way to finding plants with the highest concentrations.

Modern DNA sequencing technology was then used to identify the exact changes in DNA associated with bitterness. Nine gene changes were identified in all, leading to the direct production of the bitter compound, called cucurbitacin.

Understanding how cucerbitacin is made can now help researchers make more, opening up opportunities to extensively study its medicinal benefits.

Lucas adds that this can also allow experts to tweak other bitter or normally inedible plants, potentially developing new crops for a hungry world.

The results of this work were detailed in the journal Science.

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