title: Determination of hypericin and pseudohypericin in pharmaceutical preparations by liquid chromatography with fluorescence detection.
abstract: The quantification of the naphthodianthrones, hypericin and pseudohypericin, to which most St. John's wort pharmaceutical preparations are standardized, can be accomplished with a high degree of specificity and sensitivity with LC-fluorescence. Extraction into ethanol is rapid and recovers more than 95% of both pseudohypericin and hypericin following 1 h of sonication. This LC-fluorescence method can separate and detect both pseudohypericin and hypericin in the presence of other constituents in Hypericum perforatum with a greater degree of specificity than LC-UV at either 236 nm or 592 nm and may even be more specific than LC-MS if only the molecular ion is monitored. LC-fluorescence is also more sensitive than LC-UV at either 236 nm or 592 nm. The LC-fluorescence method can quantify on-column amounts of hypericin and pseudohypericin as low as 0.18 ng with less than 5% deviation from known and method replication error (reproducibility) less than 5.5%. Hypericin and pseudohypericin can be accurately and reproducibly quantified from capsules, tablets and tinctures of St. John's wort.
authors: Department of Pharmacy, Sunnybrook Health & Women's College Science Center, North York, Ontario, Canada.
authors: A H
authors: AH
authors: Draves
authors: S E
authors: SE
authors: Walker
mesh_terms: D000873:Anthracenes; D002853:Chromatography, Liquid / Q000379:methods*; D010569:Perylene / Q000031:analogs & derivatives* / Q000032:analysis*; D004364:Pharmaceutical Preparations / Q000737:chemistry*; D012680:Sensitivity and Specificity; D013050:Spectrometry, Fluorescence; D013056:Spectrophotometry, Ultraviolet
chemical_list: D000873:Anthracenes; D004364:Pharmaceutical Preparations; D010569:Perylene; C004965:hypericin; C056602:pseudohypericin