Fucoxanthin

A brown alga does not grow where sunlight is comfortable. A few metres down, the red end of the spectrum has already been stripped out, and what reaches the frond is mostly the blue-green band between roughly 450 and 540 nm. Fucoxanthin exists to harvest that slice: bound to chlorophyll a and c inside a light-harvesting complex, it captures the photons the chlorophylls cannot and passes the energy along. That partnership — a xanthophyll locked onto chlorophyll in the same protein — is why the pigment is one of the most abundant carotenoids in nature, and also why purifying it is more awkward than the numbers suggest.

Eata Marisource supplies fucoxanthin from brown macroalgae and from diatoms whose pigment density runs an order of magnitude higher: oil concentrates, standardised powders, water-dispersible formats and preparative-chromatography grades above 90%. Each lot leaves with an HPLC assay, the isomer split, residual solvent figures and the storage conditions the grade genuinely needs — a carotenoid certificate missing any one of those four is decoration rather than data.

Where the Pigment Actually Concentrates

The pattern is hard to miss: the richest source is not a seaweed at all. Diatoms carry roughly ten times the pigment of dried kelp per gram, which is why cultivated biomass increasingly feeds high-purity work — while macroalgae still win on raw material cost and on the co-products, alginate and fucoidan, that come out of the same harvest.

Figure 1. Supercritical CO2 extraction with an ethanol co-solvent: clean recovery, no solvent residue to declare.

The Chlorophyll Problem

Fucoxanthin never travels alone. Chlorophyll a and its degradation product pheophytin move with it through every solvent, and both are greener, more abundant and easier to see. Getting from a crude alcoholic extract to a 90%+ carotenoid is therefore a separation problem far more than an extraction problem.

• Solvent choice sets the ceiling — on Odontella aurita, methanol returned about 16.2 mg/g and ethanol about 15.8 mg/g, acetone roughly 13.9 mg/g, while petroleum ether and n-hexane pulled very little. Ethanol is usually the working compromise wherever the destination specification dislikes methanol or acetone.
• Assisted extraction — ultrasound, microwave and pressurised-liquid routes (liquefied dimethyl ether among them) shorten contact time and keep thermal exposure low, which matters the moment the pigment leaves the cell.
• Solvent-free recovery — supercritical CO2 with an ethanol co-solvent extracts cleanly and leaves nothing to declare on residual solvents — our recommended route for grades destined for formulation work.
• Polishing — silica columns handle gram scale; elution-extrusion countercurrent chromatography handles batch preparation, and has delivered 92.6–96.2% purity from Sargassum fusiforme, Laminaria japonica and Undaria pinnatifida, with chlorophyll and pheophytin recovered as usable by-products rather than waste.

Figure 2. A crude carotenoid concentrate: dark orange-red, viscous, and still carrying the chlorophyll it was harvested with.

Grades We Supply

Identity and constants stay the same whichever grade you buy: CAS 3351-86-8, C42H58O6, molar mass 658.91, insoluble in water and soluble in ethanol and lipids. Spectroscopists will recognise the absorbance near 450 nm; classical UV quantification uses an E(1%, 1 cm) of 1197 at 451 nm in methanol–water (9:1).

Figure 3. Spectrophotometric reading of an orange pigment solution — fast, but blind to what else is absorbing at that wavelength.

One Number, Two Answers

Fucoxanthin percentages quoted by different suppliers are often not comparable, and the reason is the method rather than the material. A UV reading near 450 nm counts everything absorbing in that region — cis isomers, residual chlorophyll, other carotenoids — and returns a generous figure. HPLC against a reference standard separates the all-trans peak and quantifies it, and usually reports lower. When comparing quotations, ask three questions: which method, on what reporting basis (as-is, dry matter, or the oil fraction), and is the isomer split stated. We answer all three on the certificate and will run a second method on request.

Figure 4. The separation that decides purity: the orange carotenoid band walking down the column while chlorophyll stays near the top.

Isomers: the all-trans Question

Fresh Undaria yields fucoxanthin predominantly as the all-trans geometrical isomer — around 88% in published work. The two families do not behave identically. Trans forms are the more stable of the pair and are taken up into cellular lipids faster; cis forms have shown stronger inhibitory effects in cell-assay work on HL-60 and Caco-2 lines. Processing, light and heat shift the balance, so we report the ratio instead of a single figure, and we can produce to a trans-dominant profile where the application calls for it.

Keeping It Alive

Isolated fucoxanthin is an easy molecule to ruin. Once it is out of the thallus it is sensitive to oxygen, light and heat, and the usual precautions stop being optional: nitrogen-flushed or vacuum packaging, amber glass or foil laminate, storage below 4–5 °C, and prompt use once a container is opened. Inside its native matrix the pigment is far more forgiving — a preparation made from kombu processing waste lost only about 2% of its content over six months at 4 °C, and the molecule survives ordinary drying and ambient storage while it is still bound in the seaweed.

• nitrogen-flushed or vacuum-sealed primary packaging in amber glass or foil laminate
• cold chain from release to receipt; unopened shelf life up to 24 months under recommended storage
• stabilisation options: natural tocopherols, cyclodextrin complexation, microencapsulation, water-dispersible beadlets
• a note on the certificate stating whether the grade is intended for a lipid system or a dry blend — the pigment behaves differently in each

Figure 5. Amber vials under controlled illumination: photostability is measured, not assumed.

What Lands on the Certificate

• fucoxanthin content by HPLC, with method, reference standard and reporting basis stated
• isomer profile — all-trans versus cis
• residual solvents by headspace GC; the extraction solvent history matters as much as the assay
• loss on drying (typically ≤5%), ash, and particle size distribution
• heavy metals — lead, arsenic, cadmium, mercury — plus a marine-source review covering inorganic arsenic and iodine where the destination specification asks for them
• microbiological status
• chlorophyll and pheophytin carry-over, reported rather than hidden: it is the clearest single indicator of how far purification actually went
• colour and assay trend under accelerated stability, for grades entering long development programmes

Figure 6. Golden-brown diatom culture — the densest fucoxanthin biomass available to a manufacturer, grown under lights rather than harvested from a shore.

Where It Goes

• analytical and method development: reference material, calibration standards, extraction-yield comparisons
• formulation research across lipid systems, emulsions, dry blends and encapsulated formats
• cosmetic and personal-care research, where colour behaviour and antioxidant chemistry are the draw
• aquaculture and animal-feed pigmentation studies
• cell-assay and mechanistic work, where the isomer profile becomes a variable rather than a footnote

Tailored to Specification

Most fucoxanthin orders boil down to three decisions: which biomass, which purity, which form. We can source from a named species, extract on ethanol or supercritical CO2, purify to a target percentage by preparative chromatography, hold the isomer profile inside an agreed window, choose a carrier or ship carrier-free, complex with cyclodextrin or microencapsulate for aqueous handling, and package under nitrogen in anything from gram-scale amber vials to bulk foil laminate. Send us the specification your method has to satisfy and we will build the release testing around it.

Contact us with your target assay, form and packaging, and we will come back with a specification sheet and sample support.

For Research or Industrial Raw Materials, Not For Personal Medical Use!