Chemical constituents of selected unifloral Greek bee-honeys with antimicrobial activity

► (±)-3-Hydroxy-4-phenyl-2-butanone (1) and (+)-8-hydroxylinalool (2) were isolated and structurally characterised. ► The enantiomeric ratio of 1 and 2 was determined using chiral GC-MS. ► Compound 1 should not be considered as an unambiguous marker of thyme honey. ► The combination of (+)-8-hydroxylinalool with caffeine is proposed as safer marker for citrus honey. ► Honey extracts and isolated compounds were tested for antimicrobial activity.