Analysis of Plant Complex Matrices by Use of Nuclear Magnetic Resonance Spectroscopy:  St. John's Wort Extract

Abstract

The efficiency of two-dimensional homonuclear (1)H--(1)H correlated spectroscopy and two-dimensional reverse heteronuclear shift correlation spectroscopy (i.e., heteronuclear multiple quantum correlation) in characterizing and evaluating the relative content of herbal extract constituents is demonstrated. These experiments are able to fully assign the proton and carbon resonances of all three classes of constituents present in dried commercial extract of St. John's wort, that is, flavonols, phloroglucinols, and naphthodianthrones, with particular regard to the very unstable phloroglucinols. In addition, shikimic and chlorogenic acids, sucrose, lipids, polyphenols, and traces of solvents of the extractive process (methanol) were also identified. These experiments can be considered to be a very simple and fast analytical method for determining the quality and stability of the titled commercial extract. They represent a generally applicable technique for a rapid screening and a specific measurement of other commercial phytochemicals or, in selected cases, an alternative to the classical analytical techniques such as high-performance thin-layer chromatography, high-performance liquid chromatography, capillary gas chromatography, and electrophoresis.

1H NMR determination of hypericin and pseudohypericin in complex natural mixtures by the use of strongly deshielded OH groups

“…According to Filippini and coworkers [31], although there are several HPLC methods for identification of hypericins and other constituents of H. perforatum [12,16,[20][21][22][32][33][34][35], the recoveries of hypericin, after injection in a C 18 column, is not complete, and therefore the analysis of hypericins by RP-HPLC is problematic. It has also been reported that there are significant differences in the concentrations of hypericin and pseudohypericin as measured by HPLC and UV-vis, with HPLC often giving a lower reading [18].…”

“…Antidepressant applications of St. John's wort have become increasingly popular in Europe, especially in countries like Germany where physicians prescribe herbal medicines [11]. H. perforatum medical preparations are prescribed also as dietary supplements [12]. Hypericin (Fig.…”

Recent analytical approaches in quality control of traditional Chinese medicines—A review

“…Occasionally, the different NMR solvents supply complementary data set for PCA model [112]. Except for the optimization of the NMR parameters, 2D NMR is an effective method to solve the overlapped signals [113][114][115]. Yang applied two-dimensional J-resolved NMR spectra and multivariate data analysis techniques for the analysis of commercial ginseng preparations.…”

Phytochemical analysis of isoflavonoids using liquid chromatography coupled with tandem mass spectrometry

“…Different analytical techniques such as TLC, UV, HPLC, capillary electrophoresis have been employed for analysis of isoflavonoids over the past decades (Drašar and Moravcova 2004;Liu et al 2008;Zhou et al 2009). LC methods with UV detection have questionable specificity for distinguishing compounds of very similar structures as they often exhibit fairly similar UV absorption characteristics (Bilia et al 2001;Cao et al 2008;Dachtler et al 2001;Krause and Galensa 1991;Pietta et al 1991;Qi et al 2006;Rehwald et al 1994;Tian et al 2006;Uchiyama et al 2008;Wu and Thompson 2006;Zhou et al 2008Zhou et al , 2009. Also these methods are time consuming and labour-intensive.…”