Single-Laboratory Validation of a Method for the Detection and/or Quantification of Select Alkaloids in Goldenseal Supplements and Raw Materials by Reversed-Phase High-Performance Liquid Chromatography

Abstract

Quality of botanical products and raw materials is important to manufacturers, regulators, researchers, and consumers. Many modern botanical quality-assurance schemes set specifications for select phytochemicals and measure against those specifications as one determinant of quality. While numerous publications describe procedures for determining compounds of interest in plant species, few methods have been systematically evaluated for accuracy, precision, or reliability, and often the analysis of finished products is not within the scope of the method. Hydrastis canadensis. L., commonly referred to as Goldenseal, is an economically important North American medicinal plant that has been subject to adulteration in commerce. The phytochemicals of interest in the plant are the alkaloids hydrastine, berberine, and canadine. Of interest is also palmatine, an alkaloid found in potential adulterant species but not in goldenseal. In this study, goldenseal materials in raw, capsule, and tablet form, including an Echinacea/ Goldenseal combination product, were extracted with acidified water and acetonitrile and their hydrastine, berberine, canadine, and palmitine content determined by HPLC. The analytical method was optimized and evaluated in a single-laboratory validation study. Calibration curves for hydrastine and berberine were linear from 10 to 150 μ g/mL. The limits of detection for palmatine and canadine were determined to be 0.5 μ g/mL, which translates to detection of levels of 0.004% w/w in test samples. Chromatographic resolution was achieved for all analytes in an isocratic 12.5-min chromatographic run employing a binary mobile phase. Triplicate determinations performed on 10 test materials by two analysts on 3 days resulted in relative standard deviations ranging from 0.9% to 3.4%.