Astaxanthin
[CAS# 472-61-7]

Identification

• Classification: Food additive >> Colorant >> Edible synthetic pigment
• Name: Astaxanthin
• Synonyms: 3,3'-Dihydroxy-beta,beta-carotene-4,4'-dione
• Molecular Formula: C₄₀H₅₂O₄
• Molecular Weight: 596.85
• CAS Registry Number: 472-61-7
• EC Number: 207-451-4
• SMILES: CC1=C(C(C[C@@H](C1=O)O)(C)C)/C=C/C(=C/C=C/C(=C/C=C/C=C(/C=C/C=C(/C=C/C2=C(C(=O)[C@H](CC2(C)C)O)C)C)C)/C)/C

Properties

• Density: 1.1±0.1 g/cm³ Calc.^*
• Melting point: 215-216 °C (Expl.)
• Boiling point: 774.0±60.0 °C 760 mmHg (Calc.)^*
• Flash point: 435.8±29.4 °C (Calc.)^*
• Index of refraction: 1.595 (Calc.)^*

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

Safety Data

• Hazard Symbols: GHS07 Warning
• Risk Statements: H302-H315-H319-H335
• Safety Statements: P261-P305+P351+P338

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Chronic hazardous to the aquatic environment	Aquatic Chronic	4	H413

Discovery and Applications

Astaxanthin is a naturally occurring carotenoid pigment belonging to the xanthophyll class, characterized by its red-orange color. It was first identified in the mid-20th century in marine organisms such as shrimp, krill, and certain microalgae, where it serves as a protective pigment against oxidative stress caused by ultraviolet light and oxygen radicals. Structurally, astaxanthin contains a polyene chain with conjugated double bonds and polar end groups, which confer both antioxidant properties and the ability to integrate into cell membranes, stabilizing them against oxidative damage.

The compound is widely distributed in nature, primarily in marine environments. Microalgae, such as Haematococcus pluvialis, are considered the richest natural sources of astaxanthin, where it accumulates under stress conditions, including high light intensity and nutrient deprivation. In marine animals, astaxanthin is acquired through dietary intake of algae and smaller organisms, and it is responsible for the red coloration observed in salmon, trout, shrimp, and lobster. Its presence in aquaculture feed has been extensively studied to enhance the pigmentation of farmed fish and shellfish, which is a key quality trait influencing consumer preference.

Astaxanthin has attracted significant attention due to its potent antioxidant activity. It is capable of quenching singlet oxygen, scavenging free radicals, and protecting lipids, proteins, and DNA from oxidative damage. This activity is stronger than that of many other carotenoids, including beta-carotene and lutein, making astaxanthin valuable in both nutritional and pharmaceutical applications. In human nutrition, it is used as a dietary supplement to support skin health, eye health, cardiovascular function, and immune response. Its lipid-soluble nature allows it to accumulate in tissues, enhancing cellular protection against oxidative stress and inflammation.

In addition to its nutritional benefits, astaxanthin is applied in the food and aquaculture industries as a natural colorant. It is used to improve the appearance of farmed salmon and trout and to enhance the coloration of crustaceans in processing. In cosmetics, astaxanthin is incorporated into formulations aimed at reducing skin aging and photodamage due to its ability to mitigate oxidative stress and maintain cellular integrity. Research also explores its potential in managing metabolic disorders, neurodegenerative diseases, and exercise-induced oxidative stress, although clinical applications in these areas are still under investigation.

The production of astaxanthin can be achieved via extraction from natural sources or through chemical synthesis. Natural astaxanthin derived from microalgae is preferred in nutraceutical and food applications due to higher bioactivity and consumer demand for natural ingredients. Biotechnological advances have focused on optimizing algal culture conditions to increase astaxanthin yield and purity, including controlled light, temperature, and nutrient management.

Overall, astaxanthin is a versatile bioactive compound with a long history of discovery and extensive applications in nutrition, aquaculture, cosmetics, and potential therapeutic interventions. Its antioxidant properties, natural occurrence, and safety profile make it a valuable compound for enhancing human health, improving food quality, and supporting industrial applications. Its integration into various products continues to expand as research further elucidates its biological effects and potential benefits.

References

2014. Astaxanthin Activates Nuclear Factor Erythroid-Related Factor 2 and the Antioxidant Responsive Element (Nrf2-ARE) Pathway in the Brain after Subarachnoid Hemorrhage in Rats and Attenuates Early Brain Injury. Marine Drugs.
DOI: 10.3390/md12126125

2012. Surface plasmon resonance (SPR) studies on the interactions of carotenoids and their binding proteins. Archives of Biochemistry and Biophysics.
DOI: 10.1016/j.abb.2012.01.006

2012. A novel function for a carotenoid: astaxanthin used as a polarizer for visual signalling in a mantis shrimp. The Journal of Experimental Biology.
DOI: 10.1242/jeb.066019