3′-Hydroxyechinenone is a keto-carotenoid pigment found in cyanobacteria and microalgae.

[1] Carotenoids belong to a larger class of phytochemicals known as terpenoids.

The chemical formula of canthaxanthin is C40H54O2.

It is found non-covalently bound in the orange carotenoid protein (OCP), which is a soluble protein involved in photoprotection and non-photochemical quenching of photosynthesis.

[2]