Astaxanthin as a King of Ketocarotenoids: Structure, Synthesis, Accumulation, Bioavailability and Antioxidant Properties

Abstract

Astaxanthin (3,3-dihydroxy-β, β-carotene-4,4-dione) is a ketocarotenoid synthesized by Haematococcus pluvialis/lacustris, Chromochloris zofingiensis, Chlorococcum, Bracteacoccus aggregatus, Coelastrella rubescence, Phaffia rhodozyma, some bacteria (Paracoccus carotinifaciens), yeasts, and lobsters, among others However, it is majorly synthesized by Haematococcus lacustris alone (about 4%). The richness of natural astaxanthin over synthetic astaxanthin has drawn the attention of industrialists to cultivate and extract it via two stage cultivation process. However, the cultivation in photobioreactors is expensive, and converting it in soluble form so that it can be easily assimilated by our digestive system requires downstream processing techniques which are not cost-effective. This has made the cost of astaxanthin expensive, prompting pharmaceutical and nutraceutical companies to switch over to synthetic astaxanthin. This review discusses the chemical character of astaxanthin, more inexpensive cultivating techniques, and its bioavailability. Additionally, the antioxidant character of this microalgal product against many diseases is discussed, which can make this natural compound an excellent drug to minimize inflammation and its consequences.

Enhancing the biochemical growth of Haematococcus pluvialis by mitigation of broad-spectrum light stress in wastewater cultures

“…[4][5][6] They produce astaxanthin, which is known as the 'king of ketocarotenoids' and has stormed the commercial market with its price shooting to 2.57 billion US$ in 2025 which can reach up to 3.4 billion US$ by 2027. 1,[7][8][9] However, the factors that play a role in controlling the growth of H. pluvialis, metabolism, and biochemical composition for producing value-added products are temperature, pH, light intensity, and nutrient availability. 10 Among these environmental factors, light has been acknowledged as an essential factor for microalgal growth as it is one of the key aspects that regulate the quantity of accessible energy for photosynthesis and its impact on growth.…”

Astaxanthin Isomers: A Comprehensive Review of Isomerization Methods and Analytic Techniques

“…For example, the solubility of Z -isomers dramatically improves as they change from a “crystalline state” to an “oily (amorphous) state”, which enhances the efficiency of carotenoid processing. Since most astaxanthin is present in all- E -forms in nature, purposeful isomerization methods boost the proportion of Z- isomers with more favorable physicochemical properties and biological activity. − This promotes the development of isomerization methods and analytic techniques of astaxanthin isomers.…”

Effects of Four Organic Carbon Sources on the Growth and Astaxanthin Accumulation of Haematococcus lacustris

“…Astaxanthin is used as a raw material for pharmaceuticals and functional foods because it suppresses inflammation, is nontoxic, and prevents diabetes and cancer [2,3]. By 2027, the market value of astaxanthin is expected to increase to USD 3.4 billion [4]. Astaxanthin may be synthesized chemically or extracted from natural sources.…”

“…Synthetic astaxanthin is not approved as a food supplement [7] and is less effective than astaxanthin from an algal source [8]. Natural astaxanthin has approximately 20-to 50-fold greater antioxidant activity than the synthetic version [4]. It is biosynthesized by several bacteria, fungi, and plants; the edible product is mainly produced by the microalgae Haematococcus lacustris, Chromochloris zofingiensis, Halochlorella rubescens, Ettlia carotinosa, and Rhexinema sarcinoideum [8].…”

“…Astaxanthin has a polyene system and can exist in 9-cis, 13-cis, 15-cis, and all-trans geometric isomeric forms [10]. The trans-isomeric form is more stable than the cis-isomeric form [4]. The 3S, 3 ′ S stereoisomer of astaxanthin is suitable for humans.…”