Biosynthesis of highly enriched 13C-lycopene for human metabolic studies using repeated batch tomato cell culturing with 13C-glucose

Abstract

While putative disease-preventing lycopene metabolites are found in both tomato (Solanum lycopersicum) products and in their consumers, mammalian lycopene metabolism is poorly understood. Advances in tomato cell culturing techniques offer an economical tool for generation of highly-enriched 13C-lycopene for human bioavailability and metabolism studies. To enhance the 13C-enrichment and yields of labeled lycopene from the hp-1 tomato cell line, cultures were first grown in 13C-glucose media for three serial batches and produced increasing proportions of uniformly labeled lycopene (14.3 +/− 1.2 %, 39.6 +/− 0.5 %, and 48.9 +/− 1.5% with consistent yields (from 5.8 to 9 mg/L). An optimized 9-day-long 13C-loading and 18-day-long labeling strategy developed based on glucose utilization and lycopene yields, yielded 13C-lycopene with 93% 13C isotopic purity, and 55% of isotopomers were uniformly labeled. Furthermore, an optimized acetone and hexane extraction led to a four-fold increase in lycopene recovery from cultures compared to a standard extraction.

Differential Bioavailability, Clearance, and Tissue Distribution of the Acyclic Tomato Carotenoids Lycopene and Phytoene in Mongolian Gerbils

“…Thus, we are limited to small but strategic studies of limited statistical power to test bioavailability and tissue distribution. Methodological improvements to improve yield and the use of stable isotopes are already being made and will enhance the ability of investigators to elucidate the metabolism of bioactive carotenoids and their biological importance (25,31,51). Stable isotope carotenoids are better suited for future metabolite identification based on signal strength, potential for analysis in shared MS facilities, and safety in humans.…”

“…Extinction coefficients and characteristic absorption spectra of carotenoids and respective geometrical isomers were previously published (26)(27)(28)(29)(30)(31).…”

Bioavailability of iron, zinc, and provitamin A carotenoids in biofortified staple crops

“…It has been shown that extrinsic labeling can be used for nonheme iron (as in plant foods) and zinc absorption studies in humans . Numerous studies have also investigated carotenoid metabolism using 14 C‐ and 13 C‐labeled compounds . Unfortunately, the high cost of these compounds and the labor‐intense procedures required have limited their use.…”

“…[37][38][39][40][41] Numerous studies have also investigated carotenoid metabolism using 14 C-and 13 C-labeled compounds. [42][43][44][45][46][47][48][49][50][51] Unfortunately, the high cost of these compounds and the labor-intense procedures required have limited their use.…”

Cruciferous Vegetables, Isothiocyanates, and Bladder Cancer Prevention

“…The context of the meal where cruciferous vegetables are consumed may also impact host exposure to bioactives . In recent years, many studies are showing exceptionally diverse pharmacokinetics of phytochemicals in humans as host genetics impact the metabolism and degradation of phytochemicals . Furthermore, epidemiologic studies must consider the exposures to known bladder carcinogens as critical variables and examine key interactions with diet and host genetic polymorphisms associated with carcinogen metabolism.…”