xanthophylles

Xanthophylls are a class of oxygen-containing carotenoids found in plants, algae, and some microorganisms. They contribute yellow to orange hues to many fruits, vegetables, and leafy tissues and play essential roles in light harvesting and protection against light-induced damage in photosynthetic organisms.

Chemically, xanthophylls differ from carotenes by the presence of oxygen in functional groups such as hydroxyl, carbonyl, or epoxide. This makes them more polar than hydrocarbon carotenoids. Common examples include lutein and zeaxanthin (both dihydroxylated), beta-cryptoxanthin, violaxanthin, and neoxanthin; some are precursors or products of the xanthophyll cycle that operates in chloroplasts.

In plants, xanthophylls participate in the xanthophyll cycle, helping to dissipate excess absorbed light as heat and protecting photosystems from reactive oxygen species. They also contribute to the structural organization of pigment–protein complexes in thylakoid membranes. In animals, xanthophylls are obtained from the diet and can accumulate in tissues; lutein and zeaxanthin, in particular, concentrate in the macula of the human retina and are thought to filter blue light and act as antioxidants.

Dietary sources include leafy greens (such as spinach and kale), corn, peas, egg yolk, and certain fruits and peppers. The bioavailability of xanthophylls can vary with food matrix and preparation.

Research on xanthophylls focuses on their roles in eye health, antioxidant activity, and potential protection against oxidative stress-related diseases. While some findings are supported, clear clinical recommendations remain cautious and context-dependent.