Development and evaluation of methods for determination of naphthodianthrones and flavonoids in St. John's wort.
Several major constituents in St. John's wort were determined for a homogenized plant sample. Three extraction techniques were evaluated: Soxhlet extraction, pressurized-fluid extraction (PFE), and sonication extraction. Levels of nine constituents (chlorogenic acid, rutin, hyperoside, isoquercitrin, quercitrin, quercetin, amentoflavone, pseudohypericin, and hypericin) were measured using liquid chromatography with ultraviolet/visible absorbance, mass spectrometric, and fluorescence detection. Levels of total naphthodianthrones determined by liquid chromatography (LC) with absorbance detection at 590 nm were compared with levels determined by direct spectrophotometry at the same wavelength. Additionally, the methods described in this paper were applied to several brands of St. John's wort finished products.
National Institute of Standards and Technology, Gaithersburg, MD 20899, USA.
Felicia B
FB
Williams
Lane C
LC
Sander
Stephen A
SA
Wise
James
J
Girard
D000873:Anthracenes; D005591:Chemical Fractionation / Q000379:methods; D002853:Chromatography, Liquid / Q000379:methods; D005419:Flavonoids / Q000032:analysis*; D020902:Hypericum / Q000737:chemistry*; D013058:Mass Spectrometry; D010569:Perylene / Q000031:analogs & derivatives* / Q000032:analysis
D000873:Anthracenes; D005419:Flavonoids; D010569:Perylene; C004965:hypericin; C056602:pseudohypericin