Composition and Antimicrobial Activity ofEuphrasia rostkovianaHayne Essential Oil

Abstract

Eyebright,Euphrasia rostkovianaHayne (Scrophulariaceae), is a medicinal plant traditionally used in Europe for the treatment of various health disorders, especially as eyewash to treat eye ailments such as conjunctivitis and blepharitis that can be associated with bacterial infections. SomeEuphrasiaspecies have been previously reported to contain essential oil. However, the composition and bioactivity ofE. rostkovianaoil are unknown. Therefore, in this study, we investigated the chemical composition and antimicrobial activity of the eyebright essential oil against some organisms associated with eye infections:Enterococcus faecalis,Escherichia coli,Klebsiella pneumoniae,Staphylococcus aureus,S. epidermidis,Pseudomonas aeruginosa, andCandida albicans. GC-MS analysis revealed more than 70 constituents, with n-hexadecanoic acid (18.47%) as the main constituent followed by thymol (7.97%), myristic acid (4.71%), linalool (4.65%), and anethole (4.09%). The essential oil showed antimicrobial effect against all organisms tested with the exception ofP. aeruginosa. The best activity was observed against all Gram-positive bacteria tested with the minimum inhibitory concentrations of 512 µg/mL. This is the first report on the chemical composition ofE. rostkovianaessential oil and its antimicrobial activity.