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A team of Chilean researchers significantly increased the lipoic acid content of tomatoes without negatively affecting plant growth or overall development.
Lipoic acid is a key molecule in cellular metabolism and is notable for its strong antioxidant capacity. Its ability to dissolve in both water and lipids allows it to act in multiple areas of the body.
The study was conducted by scientists from the Center for Plant Molecular Biology at the University of Chile, who set out to determine whether the antioxidant content of vegetable fruits could be enhanced without compromising plant development. The results were positive and led to the publication of the study in Frontiers in Plant Science under the title “Fruit-specific overexpression of lipoyl synthase increases both bound and unbound lipoic acid and alters the metabolome of tomato fruits.”
The project was led by Dr. María Paz Covarrubias, together with Dr. Michael Handford from the Department of Biology, Faculty of Sciences, University of Chile, along with other members of the research team, according to a press release.
Experimental results showed that overexpressing the enzyme lipoyl synthase (LIP1) increased both free lipoic acid and protein-bound lipoic acid in tomato fruits. This modification altered key metabolic pathways in the fruit while leaving plant growth and vegetative development unaffected.
Lipoic acid is unique among natural antioxidants because it plays a dual role in cells. It neutralizes free radicals, protecting cells from oxidative damage, and also serves as a cofactor for enzymes involved in energy metabolism, making it essential for cellular function.
Another distinctive characteristic of lipoic acid is that it exists in two forms: free and protein-bound. The free form mainly contributes to antioxidant defense, while the bound form is essential for the activity of enzyme complexes responsible for cellular energy production. The study demonstrated that the applied strategy successfully increased both forms in tomato fruits.
Beyond its potential benefits for human nutrition, lipoic acid is also important for the plant itself, contributing to stress responses and the regulation of fruit metabolism. This further supports interest in increasing its levels in a controlled manner.
The researchers used the Micro-Tom tomato variety, which is well suited for laboratory studies due to its small size and rapid growth.
Their approach involved activating LIP1 production exclusively during fruit ripening, preventing its expression in other plant organs such as leaves, stems, or roots. This fruit-specific strategy made it possible to boost lipoic acid levels without causing significant changes to vegetative development.
Finally, the study highlights the potential of alternative approaches, such as gene editing, which offers greater precision by modifying plant genes without introducing external genetic material and currently enjoys broader regulatory and social acceptance.
