Analysis of the hypericin and pseudohypericin content of commercially available St John's Wort preparations.

Context: The use of herbal medications and supplements has been growing worldwide with over four billion dollars a year spent on alternative medicines in the United States. St John's wort herbal preparations are generally standardized to "total hypericins" as a means of illustrating a degree of quality control to the consumer. This standardization has been based on a nonspecific method that overestimates and sums the two major naphthodianthrone compounds (hypericin and pseudohypericin) that are found in these products.

Determination of hypericin and pseudohypericin in pharmaceutical preparations by liquid chromatography with fluorescence detection.

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.