Chromatogr B Analyt Technol Biomed Life Sci. 2004
Simultaneous determination of hypericin and hyperforin in
human plasma with liquid chromatography-tandem mass spectrometry.
Riedel KD, Rieger K, Martin-Facklam M, Mikus G, Haefeli WE, Burhenne J.
Department of Internal Medicine VI, Clinical Pharmacology and Pharmacoepidemiology,
University of Heidelberg, Im Neuenheimer Feld 410, D-69120 Heidelberg, Germany.
A selective and sensitive method for the simultaneous determination of hypericin
and hyperforin--the two main active ingredients of St. John's Wort (SJW)
extract--in human plasma depending on liquid/liquid-extraction and LC/MS/MS
detection has been developed, validated after specifying the stability of
the photosensitive hypericin in plasma samples during light exposure and
applied to samples of a patient. After extraction with ethyl acetate/n-hexane
in the darkness, sample extracts were chromatographed isocratically within
6 min on a Kromasil RP-18 column. The analytes were detected with tandem
mass spectrometry in the selected reaction monitoring mode using an electrospray
ion source. The limit of quantification was 0.05 ng/mL for hypericin and
0.035 ng/mL for hyperforin. The accuracy of the method varied between 101.9
and 114.2% and the precision ranged from 4.7 to 15.4% (S.D., batch-to-batch)
for both analytes. The method was linear at least between 0.05 and 10 ng/mL
for hypericin and between 0.035 and 100 ng/mL for hyperforin. Using this
method hypericin and hyperforin were determined successfully in a patient
over seven days following discontinuation of exposure with therapeutic doses
of St. John's Wort extract.
PMID: 15556512 [PubMed - in process]