What is "fucoxanthin"

n. (context organic compound English) A carotenoid pigment found in the chloroplasts of brown algae.

Fucoxanthin is a xanthophyll, with formula CHO. It is found as an accessory pigment in the chloroplasts of brown algae and most other heterokonts, giving them a brown or olive-green color. Fucoxanthin absorbs light primarily in the blue-green to yellow-green part of the visible spectrum, peaking at around 510-525 nm by various estimates and absorbing significantly in the range of 450 to 540 nm.