(PTFS15-05-24) Assessing Plasma Accumulation of Steroidal Alkaloids and Their Metabolites in Healthy Adults Following Long-Term Tomato-Based Vegetable Juice Consumption

Objectives: Tomato steroidal alkaloids (tSAs) are gaining traction for their potential cardioprotective effects, but little is known about their fate in the body after long-term consumption. The objective of this study is to assess the metabolic fate and plasma accumulation of tSAs from a two-month long tomato-based vegetable juice intervention.

Methods: Healthy, non-obese adults (n = 79) participated in an 8-week parallel arm study where they were randomly assigned to one of three levels of commercial tomato-based vegetable juice: low (163 mL), medium (296 mL), and high (384 mL) doses or control (water, 500 mL) to consume daily. Blood plasma was collected at 3 time points: 0, 4, and 8 weeks. Steroidal alkaloids were extracted from plasma samples, then profiled and quantified using LC-MS. Fragmentation data was collected using MS/MS to aid metabolite identification. Plasma concentrations of tSAs across time points were analyzed using Kruskal-Wallis ANOVA and Wilcoxon pairwise tests.

Results: Seven unique masses and 17 chromatographic peaks were identified as tSAs or their metabolites, including modifications to the fruit metabolites like deglycosylation and phase II sulfonation. Plasma concentrations of tSAs were elevated (P < 0.05) from baseline by week 4 of consuming the medium and high dose of tomato juice, while there was no increase in the control and low dose groups throughout the intervention. High interindividual variation in plasma alkaloid concentrations were observed with a 50-fold difference in plasma tSA concentration between subjects with the lowest and highest concentrations in each dose group.

Conclusions: This is the first report of circulating tSAs after prolonged tomato-based vegetable juice consumption and shows that plasma tSA concentrations can be elevated from baseline when drinking 296 mL or more of a tomato-based vegetable juice, which is equivalent to two 5.5 fl oz cans of juice. Large interindividual variation in plasma concentrations suggests host differences in pharmacokinetics or other environmental factors such as usual diet.

Funding Sources: Research was funded by the USDA, Foods for Health Research Initiative, the Dan Wampler Endowed Fellowship for Foods and Health Research, and the US Department of Agriculture, Agricultural Research Service.