4-tyrosol

Tyrosol (2-(4-hydroxyphenyl)ethanol) is an industrially valuable phenolic compound used as a fine chemical, a synthon for pharmaceuticals such as betaxolol and metoprolol (β₁-adrenergic receptor blockers), a precursor of hydroxytyrosol, and an additive in sake. It also exhibits reported biological activities, including cardioprotective, anti-osteopenic, anti-melanogenic, and anti-inflammatory effects. Although tyrosol occurs naturally in olive oil, wine, and sake, its concentrations are low (e.g., ~25 mg·kg⁻¹ in virgin olive oil). Consequently, tyrosol can be produced by metabolic engineering in Escherichia coli from glucose or tyrosine via a pathway involving tyrosine decarboxylase, tyramine oxidase, and endogenous alcohol dehydrogenase [355].