A chromatographic and spectroscopic analytical platform for the characterization of St John's wort extract adulterations

Abstract

In the present study, a novel analytical platform is introduced, which enables both analysis and quality control of St John's wort extracts and tissue. The synergistic combination of separation techniques (including thin-layer chromatography (TLC), high-performance liquid chromatography (HPLC)) with mass spectrometry (MS) and vibrational spectroscopy is demonstrated to get deeper insights into the ingredients composition. TLC was successfully employed to identify some unknown ingredients being present in samples with Chinese provenience. On the one hand, the novel HPLC method described here allowed us to clearly differentiate between European and Chinese samples; on the other hand, this method could successfully be employed for the semi-preparative isolation of an unknown ingredient.Matrix-free laser desorption ionization time of flight mass spectrometry (mf-LDI-TOF/MS) using a specially designed titanium oxide layer was employed to identify the structure of the substance. The analytical knowledge generated so far was used to establish an infrared spectroscopic model allowing both quantitative analysis of ingredients as well as differentiating between European and Chinese provenience. Finally, infrared imaging spectroscopy was conducted to obtain knowledge about the highly resolved distribution of ingredients. The analytical platform established so far can be used for fast and non-destructive quantitation and quality control to identify adulteration being of interest according to the Deutsche Arzneimittel Codex (DAC).

The relevance of pharmacognosy in pharmacological research on herbal medicinal products

“…However, both methods have widely been applied for quality control of medicinal plants. For example, Huck-Pezzei et al [153] used NIR and AT-MIR (attenuated total reflection mid-infrared spectroscopy) for quantitative determination of chemical markers in St. John's wort raw herbs and pharmaceutical preparations, and for detection of material of Chinese origin that could be discriminated due to occurrence of kushenols G and H, characteristic constituents of Hypericum hirsutum (Fig. 6).…”

Quality control of Hypericum perforatum L. analytical challenges and recent progress

“…An RP‐HPLC method was elaborated for the distinction of SJW samples of European and Chinese origin. In European proveniences rutin, hyperoside and isoquercitrin can be found in higher quantities, and the ratio of pseudohypericin and hypericin is >1 (contrary to Chinese samples) …”

“…[39] Two HPTLC studies of SJW adulteration have been published. [10,40] Huck-Pezzei et al used a combination of analytical techniques, including TLC, HPLC, MS, NIR (near-infrared) spectroscopy and imaging methods coupled to multivariate data analysis, in an attempt to identify adulteration in 32 SJW samples (both plant material and finished products) and to differentiate between Hypericum of European and Chinese origin. HPTLC was used to identify some unusual ingredients present in Chinese samples.…”

Infrared Spectroscopic Technologies for the Quality Control of Herbal Medicines

“…St. John's wort: Huck-Pezzei et al [61] established a procedure to discriminate between pharmaceutical formulations containing either Hypericum perforatum or Hypericum hirsutum originating from China.…”

“…Summarized Quality Parameters of the Performed PLSR Calibrations for the Determination of St. John's Wort Ingredients by NIR Compared to MIR-ATR Spectroscopy[61] …”