Marigold carotenoids: Much more than lutein esters

Area of Science:

• * Plant biochemistry and metabolomics
• * Food science and nutraceuticals

Background:

• * Carotenoids are lipophilic pigments with recognized health benefits.
• * Hydroxy-carotenoids exist as free forms or fatty acid esters in plants.
• * Analyzing plant carotenoid esters is challenging, limiting understanding of native profiles.

Purpose of the Study:

• * To comprehensively identify carotenoids and their esters in marigold petals.
• * To investigate the native carotenoid profile without saponification.
• * To characterize novel carotenoid ester structures in marigold.

Main Methods:

• * Liquid chromatography with diode-array detection and atmospheric pressure chemical ionization tandem mass spectrometry (LC-DAD-(APCI+)MS/MS).
• * Analysis of marigold petal extracts with and without saponification.
• * Utilized C30 reversed-phase columns for enhanced separation.

Main Results:

• * Identified 56 carotenoid esters in marigold petals without saponification, compared to 18 carotenoids in saponified extracts.
• * Discovered 6 free carotenoids, 20 monoesters, and 30 diesters.
• * First-time identification of zeaxanthin, violaxanthin, auroxanthin, zeinoxanthin, and β-cryptoxanthin esters in marigold.

Conclusions:

• * The native carotenoid profile of marigold is significantly richer in ester forms than previously documented.
• * Advanced LC-DAD-(APCI+)MS/MS methods enable sensitive and selective analysis of diverse carotenoid esters.
• * This research expands the understanding of marigold's chemical composition and potential applications.