Liquid chromatography–tandem mass spectrometry of I3,II8-biapigenin, the major biflavone in Hypericum perforatum extracts

High-performance liquid chromatography method coupled with tandem mass spectrometry was developed for the quantitative determination of I3,II8-biapigenin. The procedure includes solid-phase extraction and separation on an XTerra MS C18. The assay was linear over a wide range; precision and accuracy were acceptable. Biapigenin was present in mouse and rat plasma after a standardized Hypericum perforatum extract. It was not detected in brain (<5 ng g−1), suggesting poor brain-to-blood permeability. Biapigenin concentrations were measurable in mice after intraperitoneal biapigenin (10 mg kg−1) but these amounted to about 2% of the equivalent systemic exposure, after correction for the contribution from residual blood.