Volume 49, Issue 9, September 2014, Pages 1533–1537
Short communication
Characterization of enzyme-catalysed endogenous β-hydroxylation of phenylethanoid glycosides in Euphrasia rostkoviana Hayne at the molecular level
- a Department of Pharmaceutical Chemistry, Semmelweis University, Research Group of Drugs of Abuse and Doping Agents, Hungarian Academy of Sciences, Hőgyes Endre u 9, Budapest 1092, Hungary
- b Institute of Biology, Department of Plant Anatomy, L. Eötvös University, Pázmány Péter sétány 1/C, Budapest 1117, Hungary
- Received 6 February 2014, Revised 20 May 2014, Accepted 21 May 2014, Available online 7 June 2014
Highlights
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- Phenylethanoid glycosides in different extracts of Euphrasia rostkoviana were identified and quantified.
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- Acteoside and eukovoside were identified in intact samples.
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- Campneoside II and β-hydroxyeukovoside were identified in enzyme treated samples.
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- We proved for the first time that a β-hydroxylase enzyme is active in eyebright tissues.
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- The enzyme-hydrolyzed extracts are a good source of isolation of β-hydroxyl phenylethanoid glycosides.
Abstract
Phenylethanoid glycosides, the main constituents of the aerial part of eyebright (Euphrasia rostkoviana
Hayne) were treated by the endogenous hydroxylase enzyme and the
concomitant biotransformation was characterized by applying
high-performance liquid chromatography with UV and MS detections and NMR
spectroscopy. In the extracts of the untreated (intact) samples,
acteoside and eukovoside were determined as main compounds. The
enzymatic treatment resulted in the quantitative transformation of these
phenylethanoid glycosides into their corresponding hydroxyl derivatives
identified as two epimers of β-hydroxyacteoside and
β-hydroxyeukovoside. As to the importance of this hydroxylation
β-hydroxyeukovoside was identified as a new compound and
β-hydroxyacteoside was described for the first time in eyebright. We
proved for first time that a β-hydroxylase enzyme is active in eyebright
tissues which can transform phenylethanoid glycosides into their
β-hydroxyl derivatives. Our new enzymatic method combined with a
preparative HPLC facilitates the isolation of β-hydroxyl phenylethanoid
glycosides from the aerial part of eyebright.
Graphical abstract
Keywords
- Verbascozide;
- Euphrasia officinalis;
- HPLC–MS;
- Endogenous enzymatic hydroxylation;
- Phenylethanoid glycoside
- Corresponding author. Tel.:
+36 1 217 0891; fax: +36 1 217 0891.
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