Marigold flavonoids coordinate emulsion stabilization, epithelial transport and gut microbiota modulation to enhance intestinal lutein absorption.

BACKGROUND

Flavonoids naturally coexisting with lutein in marigold (Tagetes erecta L.) extracts have been suggested to influence carotenoid bioavailability; however, their coordinated roles in intestinal lutein absorption remain insufficiently understood. This study systematically explored the synergistic effects of six major marigold flavonoids on lutein absorption via a multilevel strategy integrating emulsion behavior, intestinal epithelial transport and gut microbiota modulation.

RESULTS

In vitro, flavonoids stabilized lutein-containing mixed emulsion, reduced particle size, increased ζ-potential and enhanced bioaccessibility. In Caco-2 cells, they promoted lutein uptake and trans-epithelial transport, upregulated key transporters (SR-BI, CD36, NPC1L1) and reinforced tight junction integrity. In vivo, their co-administration increased lutein accumulation in eyes, liver and intestinal tissues, enhanced carotenoid cleavage enzyme activities, and reshaped gut microbiota and short-chain fatty acid production.

CONCLUSION

Marigold flavonoids facilitate intestinal lutein absorption via multiple pathways, improving the in vivo bioavailability of lutein. This study clarifies the synergistic interaction between marigold flavonoids and lutein, providing a theoretical basis for the rational application of marigold-derived flavonoids and carotenoids in functional food development. © 2026 Society of Chemical Industry.