UK scientists have demonstrated the use of tomatoes to compensate for the depleted supply of the neurochemical dopamine in Parkinson’s disease patients. Known as Levodopa or L-DOPA, the amino acid precursor has been the gold standard therapy for Parkinson’s disease since its establishment as a drug in 1967 and is an essential medicine declared by the World Health Organization (WHO).

According to scientists from the John Innes Centre (JIC), the tomato fruit as a natural source of L-DOPA also offers benefits for people who suffer adverse effects, including nausea and behavioural complications of chemically-synthesised L-DOPA.

The JIC team had earlier modified the tomato fruit by introducing a gene encoding a tyrosinase – an enzyme that uses tyrosine to build molecules such as L-DOPA – in beetroot where it functions in the production of the pigments betalains. This elevated the level of L-DOPA, specifically in the fruit – 150mg of L-DOPA per kg of tomatoes – and led to higher yields than those associated with L-DOPA production in the whole plant.

Read: Benefits of eating tomatoes

The aim now is to create a production pipeline where L-DOPA is extracted from genetically modified (GM) tomatoes and purified into the pharmaceutical product.

Parkinson’s disease is a growing problem in developing countries where access to pharmaceutical drugs such as synthetic L-DOPA is restricted. This novel use of the GM tomato could solve this problem.

Professor Cathie Martin explained: “You can grow tomatoes with relatively little infrastructure, then scale up at relatively low cost. A local industry could prepare L-DOPA from tomatoes because it’s soluble and you can do extractions. Then you could make a purified product relatively low tech which could be dispensed locally.”

Another plant that contains measurable quantities of L-DOPA is the velvet bean, Mucuna pruriens. Up to 10% of L-DOPA is found in its seeds but the plant itself may cause irritation and allergic reactions in field workers who harvest it. The beans themselves cause elevated levels of tryptamines which can cause hallucinations in Parkinson’s disease patients.