Determination of hypericin in St. John’s wort by derivative spectrophotometry

Abstract

Sum of hypericine content in St. John’s Wort was determined by second order derivative spectrophotometry without using any separation or background correction technique and reagent. Calibration curves were constructed for the 5–25 I¼g ml−1 concentration range. As a reference method, reversed phase high performance liquid chromatographic procedure was developed. Commercially available samples of St. John’s Wort were analyzed by the two methods and the results were statistically compared.