If you’ve ever heard the term “levodopa” be discussed, it was probably in regards to Parkinson’s disease. Currently, levodopa (L-DOPA) is the most commonly prescribed therapy for patients with Parkinson’s. Now, says Parkinson’s News Today, levodopa may be available from a new source: engineered tomatoes. This year, scientists created L-DOPA-enriched tomatoes, offering a scalable, accessible, and affordable option to source this treatment.
According to the Parkinson’s Foundation, levodopa was first developed in the late 1960s. Because it typically causes nausea on its own, the treatment is combined with carbidopa to treat Parkinson’s. The Foundation explains that while carbidopa helps stop nausea, it also:
prevents levodopa from being converted into dopamine prematurely in the bloodstream, allowing more of it to get to the brain.
Once it reaches the brain, L-DOPA turns into dopamine. Since Parkinson’s is characterized by dopaminergic neuron death, the ability to provide more dopamine helps inhibit the loss of motor function. While L-DOPA is often created chemically, it can also be found in plant seeds and other biological agents. However, it can be difficult to extract these from biologics without toxins or other unhealthy compounds.
As a result, researchers questioned how to create a plant or seed with a high level of levodopa that could be used to treat patients. This is especially pertinent for those in developing nations where synthetic L-DOPA may be unaffordable or difficult to access. Since tomatoes are widely grown throughout the world, and have enough vitamin C to prevent levodopa oxidation, researchers questioned if this would be a good crop to grow.
The Tomato Research
To begin, researchers from the United Kingdom’s John Innes Centre engineered a tomato plant which created high levels of L-DOPA within the tomatoes themselves. Although they performed this on a smaller scale, the researchers believe that this is scalable and can be widely implemented in various areas. Researchers used the CYP76AD6 gene to prompt the creation of tyrosinase, or enzymes which help generate L-DOPA. After inserting this gene into the tomato’s genome, levodopa began to accumulate. An estimated 150mg/kg of levodopa was found in the tomatoes.
In addition, the engineered tomatoes also showed other benefits. For example, these tomatoes also had higher levels of amino acids and antioxidants; were resistant to parasitic fungal infections; and had higher shelf-lives, allowing the tomatoes to be kept and used for up to 3-5 weeks.
There are five stages of Parkinson’s disease, a progressive central nervous system (CNS) disorder which affects movement and motor skills. In the first stage, patients may only experience slight tremors on one side of their body. However, by stage five, patients lose the ability to move, walk, stand, or live independently; they may also experience hallucinations or other neurological symptoms. Researchers believe genetics, environmental factors, and lifestyle factors all play a role in the development of Parkinson’s. Typically, Parkinson’s affects those over 50. However, in rare cases, it can begin earlier. Symptoms include:
- Muscle stiffness and rigidity
- Slowed movement
- Poor posture and balance
- Changes in speech, such as slurring or stuttering
- Tremors, particularly in the hands
- Hallucinations and dementia
Learn more about Parkinson’s.