Xanthophyll
[CAS# 127-40-2]

Identification

• Classification: Food additive >> Color protection agent
• Name: Xanthophyll
• Synonyms: Lutein; alpha-Carotene-3,3'-diol
• Molecular Formula: C₄₀H₅₆O₂
• Molecular Weight: 568.88
• CAS Registry Number: 127-40-2
• EC Number: 204-840-0
• SMILES: CC1=C(C(C[C@@H](C1)O)(C)C)/C=C/C(=C/C=C/C(=C/C=C/C=C(C)/C=C/C=C(C)/C=C/[C@H]2C(=C[C@@H](CC2(C)C)O)C)/C)/C

Properties

• Density: 1.0±0.1 g/cm³ Calc.^*
• Melting point: 196 °C (Expl.)
• Boiling point: 702.3±60.0 °C 760 mmHg (Calc.)^*
• Flash point: 269.1±27.5 °C (Calc.)^*
• Index of refraction: 1.583 (Calc.)^*

^* Calculated using Advanced Chemistry Development (ACD/Labs) Software.

Safety Data

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Chronic hazardous to the aquatic environment	Aquatic Chronic	4	H413
Eye irritation	Eye Irrit.	2	H319
Skin irritation	Skin Irrit.	2	H315

Discovery and Applications

Xanthophylls are a class of oxygen-containing carotenoid pigments found widely in plants, algae and photosynthetic organisms. Unlike carotenes, which are purely hydrocarbons, xanthophylls incorporate functional groups such as hydroxyls, epoxy, or carbonyl moieties; this gives them somewhat greater polarity while retaining the long conjugated chains responsible for their yellow-to-red colour. In leaves, most young green tissues contain a “xanthophyll” band visible in chromatography, which is how the term was historically coined (from the Greek “xanthos” = yellow, “phyllon” = leaf).

The discovery of xanthophylls as distinct plant pigments dates from classical botanical and chromatographic studies in the 19th century, when yellow pigments were separated from chlorophyll and identified as accessory pigments in the thylakoid membranes. With the advent of modern analytical methods, many specific molecules—such as Lutein, Zeaxanthin, Violaxanthin and Fucoxanthin—have been structurally characterised and their biosynthetic pathways (derived from isoprene/terpenoid precursors) elucidated. Xanthophylls play critical roles not only in light harvesting but also in photoprotection: under high light stress, some xanthophylls are converted via the xanthophyll cycle (for example violaxanthin → antheraxanthin → zeaxanthin) to dissipate excess energy as heat and protect the photosynthetic apparatus from damage.

In terms of application, xanthophylls are important for both plant physiology and human health. From the plant side, the xanthophyll cycle helps stabilize light absorption under fluctuating and often excess illumination, supporting crop productivity and stress resilience. ([OUP Academic][3]) From the human nutritional side, xanthophylls such as lutein and zeaxanthin selectively accumulate in the macula of the human retina and appear to protect eye health, especially in age-related macular degeneration (AMD). Dietary intake of xanthophyll-rich foods and supplements has been linked to improvements in macular pigment optical density and visual function in both healthy individuals and patients with retinal pathology. ([Frontiers][4]) Additionally, xanthophylls derived from algae and marine sources (for instance fucoxanthin in brown seaweed) have been studied for anti-inflammatory, antioxidant, anti-tumour and metabolic effects.

From a chemical-functional perspective, xanthophylls’ oxygenated nature enhances their interaction with lipid membranes and their antioxidant behaviour. They are lipophilic yet more polar than carotenes, enabling stronger association with membrane bilayers and perhaps facilitating interactions with specific binding proteins (such as in the retina). Research analysing xanthophyll–membrane interactions indicates that their orientation and selective deposition in neural tissues contribute to their protective effects in the brain and eye.

In summary, xanthophylls represent a biochemically and physiologically significant group of pigments characterised by oxygenated carotenoid structures. Their discovery as plant pigments evolved into deep investigations of their roles in photoprotection, human nutrition and health. Today, they find broad applications in agricultural science, nutritional formulations and potentially in functional food or therapeutic research, underscoring the wide significance of this class of compounds.

References

Thomas SE & Johnson EJ (2018) Xanthophylls. Advances in Nutrition 9(2) 160–162. DOI: 10.1093/advances/nmx005

Dall'Osto L, Fiore A, Cazzaniga S, Giuliano G & Bassi R (2007) Different roles of &apha;- and β-branch xanthophylls in photosystem assembly and photoprotection. Journal of Biological Chemistry 282(48) 35056–35068. DOI: 10.1074/jbc.M704729200

Fernández-Marín B, Roach T, Verhoeven A & García-Plazaola JI (2021) Shedding light on the dark side of xanthophyll cycles. New Phytologist 230(4) 1336–1344. DOI: 10.1111/nph.17191