Separation of α‐retinyl palmitate and quantification of vitamin A after consumption of carrots containing α‐carotene (645.24)

Abstract

Vitamin A (VA) is vital for proper growth, vision, and immune function. Provitamin A carotenoids are an important source of VA for humans, yet the bioequivalence of VA from nonsymmetrical provitamin A carotenoids is poorly characterized. In humans, α‐carotene (αC) is cleaved to VA and inactive α‐retinol (αR) ‐ both of which are esterified with palmitate (P). Analytical methods are needed to separate VA esters from αRP to avoid overestimation of the VA bioequivalence of αC containing foods. To accurately assess the VA obtained from an αC‐rich meal, an αRP standard was synthesized from α‐ionone following adapted methods based on the Wittig‐Horner reaction. A high performance liquid chromatography‐tandem mass spectrometry (LC‐MS/MS) method was developed to resolve αRP from VA esters. Separation was confirmed by MS, where parent ester m/z and differing intensities of daughter ions allowed for distinction of αRP from VA esters. The developed LC‐MS/MS method was applied to the analysis of post‐prandial triglyceride rich lipoprotein fraction of plasma from healthy humans after consumption of carrots and αRP and VA esters were individually quantified. These results provide important insights about the fate of αR in humans consuming αC‐rich foods and the bioequivalence of VA from commonly consumed nonsymmetrical provitamin A carotenoids.Grant Funding Source: Supported by The Ohio State University Food Innovation Center