The use of spices such as garlic, oregano or allspice with antimicrobial and antifungal effects has been one of the reasons for the evolutionary success of humans. But what if a vegetable as common on our plates as tomatoes could also destroy microorganisms? A new study points in that direction.
Tomatoes (Solanum lycopersicum) are one of the most consumed vegetables in the world. Global fresh tomato production in 2021 amounted to just over 189.1 million tons, making it the second most important horticultural crop after potatoes.
While its nutritional and health-promoting properties due to its bioactive molecules (lycopene, polyphenols and vitamins, among others) have been widely studied and linked to a wide range of health benefits, information on its antimicrobial properties was very scarce.
Now, in research just published in Microbiology Spectrum, scientists at Cornell University have shown that tomato juice can kill Salmonella Typhi and other bacteria that damage the human digestive and urinary tract.
Typhoid fever, a potentially lethal fecal-oral transmitted infectious disease that affects millions of people each year, is caused by the bacteria Salmonella enterica, serovariant Typhi (Salmonella Typhi, hereinafter). This bacteria only lives in the blood and digestive system of humans. It is the main cause of mortality caused by infections by enteric pathogens. Every year there are 21 million cases of typhoid fever, causing 200,000 deaths worldwide.
Typhoid fever can be treated with antibiotics, although increasing resistance to them makes it increasingly difficult. On the other hand, and despite the availability of vaccines against typhoid fever, many developing countries continue to face insurmountable obstacles in accessing them.
The research on the role of tomato was carried out in several phases. First, researchers demonstrated through laboratory experiments that tomato juice actually has antibacterial properties. Once its effectiveness was proven, they computer analyzed the tomato genome to find the antimicrobial peptides (AMP) responsible for the process. This is how they identified two powerful AMPs capable of destroying bacteria.
Antimicrobial peptides are naturally occurring proteins that have antibiotic properties. These are components of the innate immune response conserved in different evolutionary processes and that play a crucial role in combating infections caused by bacteria, fungi and viruses.
Their rapid antimicrobial activity is due to the fact that they directly attack the lipid bilayer of the cell membrane of microbes, forming pores that, ultimately, lead to membrane permeabilization and subsequent bacterial death. In addition to their direct antimicrobial properties, AMPs have the ability to modulate immune responses and stimulate the release of cytokines and chemokines, proteins that have immune-stimulating or depressing effects and are used to help the body fight cancer. , infections and other diseases.
Once these two AMPs were identified, the team conducted further tests on different variants of the bacteria that appear in places around the world where the disease is common.
Finally, they tested the effectiveness of tomato juice against other enteric pathogens that can damage the digestive and urinary tracts. As a result, they found positive responses of both antimicrobial peptides against Salmonella Typhi, non-typhoid salmonella (Salmonella Typhimurium) and strains of Escherichia coli that cause urinary tract infections, such as cystitis.
In summary, this study provides valuable information on the potential utilization of tomatoes as a natural antimicrobial food source for public health promotion. Given the wide distribution of crops in very different climatic conditions, tomatoes have considerable potential to stop pathogenic bacteria.
This article was originally published on The Conversation. Manuel Peinado Lorca is Director of the Royal Botanical Garden of the University of Alcalá.
