Euphrasia officinalis L. (eyebright) is a valuable plant in traditional medicine as a remarkable remedy
for inflamed eye disorders since ancient times. Our knowledge is still lacking exact
details in phytochemical composition, and way of mechanism of active compounds of
eyebright. Our aim was to contribute to the phytotherapeutical revaluation of Euphrasia officinalis L. by investigating the main chemical groups of the herb and to understand their
role in the inflammatory process, in which free radicals are considered to play a
significant role via different biochemical pathways. After a successive extraction
of Euphrasiae herba with n-hexane, chloroform, ethyl-acetate and methanol, as follows, the main compounds
were identified as iridoids and phenolics/flavonoids. The content of Flavonoids, polyphenols,
tannins and hydroxycinnamic derivatives were determined, results are: 0.38g/100g,
1.47g/100g, 0.56g/100g, 1.97g/100g, respectively. Then preliminary assays were performed
to study the free radical scavenging activity (DPPH, ABTS and TBA assay). The lyophilised
decoctum of Euphrasiae herba showed a considerable scavenging activity, so it was reasonable to elucidate the
main chemical groups, and find correlation between the active compounds and the free
radical scavenging activity. Methanolic extract of eyebright herb was fractionated
by polyamid column chromatography using water (7 fractions: iridoids) and methanol
(8 fractions: phenolics/flavonoids). For the qualitative analyses of the fractions
TLC, HPLC and LC-MS/MS methods were developed and used. We have found that the fraction
containing simple caffeoyl-derivatives provided the highest scavenging activity in
both DPPH and ABTS assays. Those fractions which were rich in flavonoids were also
notable antioxidants. The scavenging effect of Euphrasia officinalis L. is a combination of the iridoids and phenolics/flavonoids, however the phenolic
components basically determine the effect.
