title: Simultaneous determination of total hypericin and hyperforin in St. John's wort extracts by HPLC with electrochemical detection.
abstract: An analytical procedure was developed for the simultaneous determination of total hypericin (protopseudohypericin, pseudohypericin, protohypericin and hypericin) and hyperforin in Hypericum perforatum (St. John's wort) extracts and its preparations. The determination of total hypericin and hyperforin in one step was achieved by exposing the samples to artificial daylight in amber glass vials. This procedure allows both the photoconversion of the protoforms into the appropriate hypericins and the protection of the photosensitive hyperforin. For quantification, an HPLC method with electrochemical detection was applied. As an example of the application of the principle, two preparations containing St. John's wort were assayed.
authors.affiliation: Institut für Pharmazeutische Wissenschaften, Karl-Franzens-Universität Graz, Schubertstrasse 1, A-8010 Graz, Austria.
authors.forename: Ulla
authors.initials: U
authors.lastname: Rückert
authors.forename: Werner
authors.initials: W
authors.lastname: Likussar
authors.forename: Astrid
authors.initials: A
authors.lastname: Michelitsch
mesh_terms: D000873:Anthracenes; D000928:Antidepressive Agents / Q000737:chemistry; D001643:Bridged Bicyclo Compounds / Q000032:analysis / Q000737:chemistry / Q000528:radiation effects; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D004563:Electrochemistry / Q000379:methods*; D020902:Hypericum / Q000737:chemistry*; D008027:Light; D010569:Perylene / Q000031:analogs & derivatives* / Q000032:analysis / Q000737:chemistry / Q000528:radiation effects; D010696:Phloroglucinol / Q000031:analogs & derivatives* / Q000032:analysis / Q000737:chemistry / Q000528:radiation effects; D010936:Plant Extracts / Q000737:chemistry; D011208:Powders / Q000737:chemistry; D013607:Tablets / Q000737:chemistry; D013729:Terpenes / Q000032:analysis* / Q000737:chemistry / Q000528:radiation effects
chemical_list: D000873:Anthracenes; D000928:Antidepressive Agents; D001643:Bridged Bicyclo Compounds; D010936:Plant Extracts; D011208:Powders; D013607:Tablets; D013729:Terpenes; D010569:Perylene; C004965:hypericin; D010696:Phloroglucinol; C001654:hyperforin