Lutein, esters, congeners & metabolites

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Stakeholder panel on dietarysupplements Background & Fitness for Purpose Lutein, esters, congeners & metabolites Rick Myers, PhD AOAC Annual Meeting Log Angeles, CA 25 September 2015 Background on

1 Stakeholder panel on dietarysupplements Background & Fitness for Purpose Lutein, esters, congeners & metabolites Rick Myers, PhD AOAC Annual Meeting Log Angeles, CA 25 September 2015 Background on analytes Carotenoids are a diverse family of botanical pigments Minimal biosynthesis in animals; so must derive from diet Botanical function Mediate photoinduced electron transfer to chlorophyll Quench singlet/triplet chlorophyll that can damage allied tissues during very active photosynthesis Two relevant carotenoid families Carotenes: hydrocarbons (orange) Xanthophylls: hydroxylated carotenes (yellow) Only xanthophylls of interest here. Dozens exist! Often exists as fatty acid esters in nascent tissue

2 Proposal for analytes: 1. Limit to only principal isomers of the four most relevant, co chromatographing compounds a. Lutein b. 3 Epilutein (significant epimer loss of lutein) c. Zeaxanthin d. β Cryptoxanthin 2. Saponify initial extract a. Analyze free compounds only 1. Lutein o (3R,3 R,6 R) β,ε carotene 3,3 diol; 3 R β ε 33 diol; dietary o Commercial and supplemental roles Accumulates throughout human retina Reportedly rescues AMD Present in other tissues, relevance under study Colors white egg yolks yellow Antioxidant Colorant (E161b) o Structure o Proposed daily dose: 10 mg

3 2. Zeaxanthin o β,β carotene 3,3β 33' diol; dietary o Zeaxanthin differs from lutein only by placement of single double bond. o Commercial and supplemental roles Also accumulates in human retina; predominates in macula lutea Reportedly rescues AMD Colors white egg yolks yellow Colorant (E161h) o Structure o Proposed daily dose: 2 mg 3. β Cryptoxanthin o (3R,3 R,6 R) R) β,ε carotene 3,3β ε 33 diol; dietary o Commercial and supplemental roles Provitamin in humans; converted to vitamin A Possible antioxidative DNA protection, bone health, others Colorant (E161c) in Australia and New Zealand; not in US or EU o Structure o Proposed daily dose: 4 mg

4 4. 3 Epilutein o (3R,3 S,6 R) lutein o Not dietary no biological or commercial role o Significant epimer product and loss of lutein o Occurs in aqueous acid o Reaction likely proceeds by S N 1 and S N 2, but mostly S N 2 since conversion exceeds 50% o Structure General Analytical Needs Method should Quantitatively de esterify all analyte forms Separate and accurately quantify relevant free analytes Lutein Zeaxanthin β Cryptoxanthin 3 Epilutein (principal lutein metabolite) Determine the above in Raw materials used in dietary supplement formulations Finished products?

5 Challenges Quantitative recovery from finished product forms, e.g., beadlets, softgels, etc. Dozens of carotenoids co extract from their botanical sources Analytes are difficult to separate from one each other, isomers, and metabolites Existing Methods General HPLC UV U/HPLC MS/MS

6 Representative existing methods USP FCC 7 monograph Total carotenoids HPLC UV Normal phase (silica) Mobile phases: hexane, EtOAc AOAC Lycopene in dietary supplements and raw materials Protease digestion and extraction with DCM:EtOH HPLC UV (alkylamide bonded silica) Mobile phase: IPA:NH 4 OAc: ACN:MeOH:alkylamine A complex extract requires both normal and reversed phase chromatography for robust separation Khachik et al. (1997) and Khachik et al. (1992) Carotenoids and their metabolites in human milk and serum, and Carotinoids and their oxidation products in human plasma, respectively Two complementary chromatographic methods 1. Reversed phase (C 18 ), ACN:MeOH:DCM, UV/MS 2. Normal phase (Nitrile bonded silica), hexane:dcm:meoh: alkylamine, UV/MS AOAC β Carotene in dietary supplements and raw materials Protease digestion and extraction with DCM:EtOH Two complementary HPLC chromatographic methods 1. Reversed phase (C 18 ), IPA:NH 4 OAc: ACN:MeOH:alkylamine, UV 2. Reversed phase (C 30 ), MeOH:MTBE:alkylamine, UV

7 Regulatory Guidance Evaluation of the Joint FAO/WHO Expert Committee on Food Additives (JECFA), 2004 The FDA has confirmed the Joint Expert Committee on Food Additives (JECFA) ruling (Sept 8, 2004) that free lutein and zeaxanthin are safe for human consumption. Vitamin status in some countries General Method Requirements 1. Quantitative i extraction from matrices a. Raw materials from which dosage forms are formulated b. Finished products (e.g., softgels, beadlets) including proteolytic or other matrix release methods 2. Ensure against losses (e.g., oxidation, photolysis) during extraction, workup and analysis 3. Separation from matrix interferent for accurate and reproducible quantitation 4. The analytical range of the chosen method must encompass below 1 mg

8 Fitness for Purpose (proposal) Quantitative measurement of lutein, 3 epilutein, zeaxanthin and β cryptoxanthin in both raw materials from which dosage forms are formulated; and in finished products (e.g., softgels, beadlets). Methods must be able to accurately measure in the analytical range below 1 mg per dosage unit. Questions to address Addressextractionfrom extraction botanical tissues? Esters? Or free compounds only (saponify first)? Quantify losses: To epilutein? Only all trans species (or include cis species)? Oxidized species? Lutein only, or include: Zeaxanthin? β Cryptoxanthin? Others?

9 QUESTIONS?

Irena Vovk 1, Breda Simonovska 1, Danica Agbaba 2 and Gordana Popović 2

Lutein in food supplements Irena Vovk 1, Breda Simonovska 1, Danica Agbaba 2 and Gordana Popović 2 1 National Institute of Chemistry, Ljubljana, Slovenia 2 University of Belgrade, Faculty of Pharmacy Why