Discovery of steroidal alkaloid metabolites and their accumulation in pigs after short-term tomato consumption

Authors: SHOLOLA, MARIA - The Ohio State University; GOGGANS, MALLORY - The Ohio State University; Dzakovich, Michael; FRANCIS, DAVID - The Ohio State University; JACOBI, SHEILA - The Ohio State University; COOPERSTONE, JESSICA - The Ohio State University

Submitted to: Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/16/2024
Publication Date: 9/17/2024
Citation: Sholola, M.J., Goggans, M.L., Dzakovich, M.P., Francis, D.M., Jacobi, S.K., Cooperstone, J.L. 2024. Discovery of steroidal alkaloid metabolites and their accumulation in pigs after short-term tomato consumption. Food Chemistry. https://doi.org/10.1016/j.foodchem.2024.141346.
DOI: https://doi.org/10.1016/j.foodchem.2024.141346

Interpretive Summary: Tomato steroidal alkaloids are bioactive compounds that are hypothesized to contribute to the health benefits associated with tomato consumption. However, they have never been quantified in plasma before. This information is needed better help scientists understand their potential capability to alter health outcomes. We found 31 peaks that represented 9 different types of steroidal alkaloid metabolites in blood plasma. The average total concentration was 107.7 nmol/L and nearly 80% were present as aglycones or without sugar groups that are normally attached to these compounds within the plant. Some of the metabolites found were also due to detoxification processes that naturally occur in mammals. Our findings represent an important step towards understanding how steroidal alkaloids from tomatoes are absorbed and metabolized and provides context for how to conduct future clinical studies aimed at better understanding their bioactivity.

Technical Abstract: Whole tomato consumption has been shown to be more effective than lycopene alone against several chronic disease risks and outcomes, suggesting other phytochemicals play a role in the health properties of tomato-rich diets. Recently, metabolites of tomato steroidal alkaloids, an understudied class of secondary plant compounds, have been found in plasma, tissues, and urine. However, a comprehensive, targeted analysis to discover which steroidal alkaloid metabolites are present after tomato consumption is lacking. In this study, steroidal alkaloids derived from tomatoes are profiled and quantified in blood plasma for the first time. We conducted a parallel arm study in weaned piglets (aged three weeks), which were fed an ad libitum diet containing 10% tomato powder (n = 10) or a macronutrient matched control diet (n = 10) for two weeks. Steroidal alkaloids and their metabolites were extracted from blood plasma with methanol and quantified using LC-MS. Tomatidine and alpha-tomatine were detected in plasma and confirmed with standards. For the remaining steroidal alkaloids, mass fragmentation spectra were utilized to identify the compounds with level 2 annotations. Analytes were quantified with a matrix-matched calibration curve and 31 peaks (representing 9 unique steroidal alkaloid masses) were attributed to steroidal alkaloids. Total tomato steroidal alkaloid concentrations averaged to 107.7 nmol/L pig plasma, with 78% of metabolites present as aglycones. The remaining metabolites were phase I (66%) and phase II (4.5%) metabolites, namely from hydroxylation and sulfonation. These results describe the profile and concentration of steroidal alkaloid metabolites in pig plasma after short-term tomato consumption. This methodology and findings allow for future investigations of tomato steroidal alkaloid bioactivity using physiologically appropriate levels.