Genetically editing tomatoes increases their anti-inflammatory activities, study finds

20 Feb 2023 --- Researchers in Tokyo, Japan, genetically modified tomato and potato plants to produce betacyanin and tested the extracts’ therapeutic benefits. Betacyanin is a type of betalain red-violet and water-soluble pigment with potent antioxidant potential.

The results showed that the genetically altered tomato plants showed higher anti-inflammatory properties than wild tomatoes.

NutritionInsight speaks with the study’s lead author, professor Gen-ichiro Arimura from the Tokyo University of Science, regarding the study’s impact. 

“Since betalains are just pigments and their safety is assured, I believe that metabolic engineering of this compound will contribute to the widespread use of recombinant plants in general.” 

The study was published in Biotechnology & Bioengineering and conducted by the Tokyo University of Science and the Iwate Biotechnology Research Center in Japan. 

Power of plants  
“Up to now, transgenic crops have not been frequently explored for their therapeutic uses,” says Arimura. “Therefore, our study is at the frontier in this regard.”

The researcher believes that functional recombinant plants will be a step toward motivating people to use them. 

“Plants have unique, functionally specialized compounds (e.g., isoflavone in soybeans and lycopene in tomatoes) and it is quite possible to create a highly functional crop by modifying plants that do not originally have those compounds, such as betalains in tomatoes.” 

Researchers edited the genes of tomatoes to produce betacyanin pigments, which have anti-inflammatory effects. He adds that using such plants helps prevent various diseases without relying on supplements. 

Therapeutic effects 
“In this study, we focused on analyzing the anti-inflammatory function of betalain recombinant tomatoes as a model,” explains Arimura. He adds, “betalain may also be effective against other, multiple diseases because of its high antioxidant activity.”

The researchers add that previous tests of betalains in animal cells and model animals have shown the antioxidant activities of these ingredients.  

“Moreover,” adds Arimaru, “as mentioned in the paper, betalains are sensitive to heat, so it is highly feasible to produce betalains in tomatoes that can be eaten raw.”

Natural plant sources of betalains, such as beetroot, demonstrate poor stability in high temperatures and extreme pH.

Set-up of the research
The researchers engineered potato tubers and tomato fruits that co-express genes that produce betacyanin. The team took these genes from beets (Beta vulgaris) and the ornamental plant Mirabilis jalapa. 

Arimura explains that this transformation “enhanced the endogenous accumulation of betanin and isobetanin – two common types of betacyanin – in these transgenic vegetables.” 

“The accumulation of these pigments made them appear dark red upon maturation, compared to their wild-type counterparts.”

Next, the researchers tested the therapeutic efficacy of the altered vegetables in macrophages, a type of white blood cell that plays a vital role in inflammatory diseases. Testing showed that transgenic tomato fruit extracts exerted higher anti-inflammatory activities than extracts from wild tomatoes. 

Transgenic potatoes did not show the same therapeutic effects. According to the researchers, this could be due to unknown antagonists that work against the anti-inflammatory function of betacyanin. More testing is needed to confirm this speculation.  

Arimuri notes, “one possible limitation is the lack of proof in clinical trials.” 

Use of genetic plant editing “Functional recombinant plants will be a step toward motivating people to use them,” according to Arimuri. 
According to the researchers, betalain engineering is a promising avenue to improve the commercial production of healthy foods.

The nature-derived pigments are already used in food manufacturing industries worldwide. The colorants are also toxicologically safe to consume, accessible, biodegradable and available at low prices. 

NutritionInsight previously reported on a study that developed Vitamin D-enriched tomatoes. Gene editing allowed the building blocks of vitamin D3 to accumulate in the fruit. 

The UK is in the final stages of passing a Genetic Technology (Precision Breeding) bill that enables food producers to use genetic technologies. 

However, in the EU, food and environmental organizations recently joined forces to oppose proposed food gene-editing regulation. They claim it would allow foods to reach markets without undergoing extensive analysis before approval. 

By Jolanda van Hal