Eyebright, Euphrasia rostkoviana Ha

Eyebright, Euphrasia rostkoviana Hayne (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. Some Euphrasia species have been previously reported to contain essential oil. However, the composition and
bioactivity of E. rostkoviana oil 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, and Candida 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 of P. aeruginosa.The best activity was observed against all Gram-positive bacteria tested with the minimum inhibitory
concentrations of 512