Амбреїн

Ambrein has the formula C₃₀H₅₂O and a molar mass of 428.745 g/mol. Its structure is a tricyclic triterpene alcohol with one tertiary hydroxyl group and two double bonds.

Origin and Production

Ambergris is a solid, waxy, flammable substance of a dull grey or blackish colour produced in the digestive system of sperm whales. Ambergris takes years to form. In the sperm whale, coprolith formation is linked to the indigestible horny beaks of squid, its principal food, which may occasionally pass through the intestines and form a faecal concretion in the rectum. Only an estimated one percent of sperm whales produce ambergris. After excretion, ambergris floats in the ocean and is sometimes collected on beaches after being washed ashore. The ban on commercial whaling by many countries has increasingly limited its sources. Freshly produced ambergris smells marine and faecal. After months to years of photodegradation and oxidation at sea, it takes on an odour that is sweet, earthy, marine and animalic.

Chemistry

The main constituents of ambergris are ambrein, epi-coprosterol, coprosterol, cholesterol and coprostane-3-one. Analyses of 43 samples of jetsam ambergris showed an ambrein content of 81.1 ± 22.1%. Breakdown of ambrein through oxidation produces ambroxide and ambrinol, the main odour components of ambergris. The weathering and ageing of floating ambergris improves its quality for perfumery, as the scentless ambrein is oxidized to various odorous products.

Ambroxide

Ambroxide is an autoxidation product of ambrein, with a woody, musky and slightly salty scent. In perfumery it is used to build ambergris notes and as a fixative.

Biosynthesis

Ambrein is synthesized from the common triterpenoid precursor squalene. Squalene-hopene cyclase catalyzes the cyclization of squalene into the monocyclic 3-deoxyachilleol A. Tetraprenyl-beta-curcumene synthase converts 3-deoxyachilleol A into the tricyclic ambrein.

Biological Activity

Ambrein has been shown to act as an analgesic and has been proven to increase sexual behavior in rats. It has also been shown to decrease spontaneous contractions of smooth muscles in rats, guinea pigs, and rabbits. Ambrein reduces these contractions by acting as an antagonist and interfering with Ca²⁺ ions from outside the cell.