Ectoine Functions and Benefits in Skin and Eyes

What is Ectoine?

Ectoine is an important natural secondary metabolite in halophilic microorganisms. It protects cells against environmental stressors, such as salinity, freezing, drying, and high temperatures. Ectoine is widely used in medical, cosmetic, and other industries.

(S)-2-Methyl-1,4,5,6-tetrahydroprimidine-4-carboxylic acid, commonly known as ectoine (Fig. 1), is a cyclic amino acid derivative of aspartate, with the molecular formula C6H10N202 and a molecular mass of 142.16. It was first isolated from Ectothiorhodospira halochloris by Galinski et al. Ectoine is a polar, soluble, and uncharged small organic compound. It can alleviate the effects of high osmotic pressure, high temperature, freeze-thawing, dehydration, radiation, and organic chemical reagents on proteins, nucleic acids, biofilms, and whole viable cells.

Synthesis of Ectoine

The synthetic pathway of ectoine belongs to the aspartate family metabolism branch. The ectoine synthesis pathway, occurring from the precursor metabolite L-aspartate-ß-semialdehyde (ASA), comprises the sequential activities of three enzymes: 2,4-diaminobutyrate acetyltransferase (EctA), L-2,4- diaminobutyrate transaminase (EctB), and ectoine synthase (EctC). First, L-aspartate-β-semialdehyde is catalyzed to L-2,4-diaminobutyrate (DABA) by L-2,4-diaminobutyrate transaminase (EctB). DABA is then converted to N-acetyl- 2,4-diaminobutyrate (ADABA) by 2,4-diaminobutyrate acetyltransferase (EctA). Finally, ADABA is catalyzed to ectoine by ectoine synthase (EctC). In some microorganisms, ectoine can be further transformed to hydroxyectoine by a hydroxylase (EctD) (Fig. 2).

Functions and Benefits in Skin and Eyes

Ectoine contains agents that protect enzymes, DNA, and whole cells against stresses, such as freezing, drying, and heating. In recent years, additional properties of interest were found for ectoine. Ectoine is thought to counteract the effects of UV-A-induced and accelerate skin aging, which is why it is used as a dermatological cosmetic additive in moisturizers for the care of aged, dry, and irritated skin. Ectoine is highly effective and safe as a whitening agent. It also reduces melanin production and is non-cytotoxic.

Ectoine is used in ophthalmic preparations and has been shown to stabilise the tear film, relieve inflammation and allergic reactions in the eyes, and may reduce itching and burning sensations in the eyes. And Ectoine eye drops can be used multiple times a day and are well tolerated.

Ectoine is also used as a therapeutic for Alzheimer's disease, HIV, intestinal diseases, oral diseases, inflammatory and immunological diseases, and other diseases.

References:

[1] JUN CHEN. Biotechnological production of ectoine: current status and prospects.[J]. Folia microbiologica, 2024. DOI:10.1007/s12223-023-01105-4.