This project developed advanced multi-omics methodologies to identify neuroprotective and neuro-disrupting compounds in tomatoes, including their metabolites before and after digestion, as well as in fecal samples. The research aimed to evaluate the neuroactive profile of tomatoes, investigate the fate of these compounds once digested, and assess their impact on the human gut microbiome. The first experiment focused on profiling neuroactive compounds in four tomato types: organic and conventional datterini tomatoes, conventional plump tomatoes, and processed tomatoes. Principal Component Analysis revealed that the major differences in compound profiles were between the different processing methods and types of tomatoes, rather than between production methods (organic vs. conventional). Over 70 compounds were identified, including neuroprotective (e.g. polyphenols, amino acids, neurotransmitters) and neuro-disrupting compounds (e.g. pharmaceuticals, food additives). The annotation strategy also helped identify markers specific to certain conditions, such as markers of organic production, variety, and process, as well as non-group-specific neuroactive compounds. Processed tomatoes contained the highest number of neuroactive compounds, which did not suggest lower food quality, nor was higher quality observed for organically produced tomatoes. Additionally, smaller varieties were found to be richer in terms of nutritional value. The carotenoid distribution analysis suggested that the majority of carotenoids were concentrated in the tomato peel rather than the fruit body. While most compounds were neuroprotective, our study shows that their presence was accompanied by neuro-disrupting compounds.
In vitro-simulated gastrointestinal digestion and colon fermentation models were used to study the fate of neuroactive compounds in the gut microbiome. The kinetics of different compounds during digestion and fermentation focused on bioaccessibility, bioavailability, biotransformation, and excretion patterns. Key findings include:
- Some compounds showed a preference for excretion via urine.
- Others reached the colon, and a few demonstrated potential for crossing the blood-brain barrier, including certain neuro-disrupting compounds.
- The presence of tomato or neuro-disrupting compounds influenced the behaviour and bioavailability of some compounds.
Fermentation revealed differences between samples with and without digested tomatoes, as well as between tomato samples with and without neuro-disrupting compounds. However, the number and amount of neuroprotective compounds were higher when tomato was present in the fermentation sample.
The project developed a robust non-targeted analysis workflow using mass spectrometry and statistical methods for filtering mass features. Tools such as MZmine, Sirius, and GNPS were employed to tentatively identify unknown compounds (e.g. fructosyl pyroglutamate, bile acids). The analysis of short-chain fatty acids, and metagenomics revealed effects on the gut microbiome. Although no significant changes in reactive oxygen species levels were found, short-chain fatty acids and bile acids formation were influenced by the presence of neuroactive compounds.
The project has been experimentally completed, and data has been processed and discussed. Some preliminary results were presented at two research conferences. The full findings are expected to be published in two papers by January 2025, with at least two more papers expected by May 2025. All R-codes, raw and processed data, and publications will be made publicly available in trusted repositories (Zenodo, GitHub) once the papers are published.
