Wikipedia
Brassicasterol
Brassicasterol (24-methyl cholest-5,22-dien-3β-ol) is a 28- carbon sterol synthesised by several unicellular algae ( phytoplankton) and some terrestrial plants, e.g., oilseed rape. This compound has frequently been used as a biomarker for the presence of (marine) algal matter in the environment.