Investigators from the University of California at Davis, USA, determined the variability in a range of ginseng herbal products available in the United States.
|Variability in herbal compounds from labeled amounts:|
Ginsenosides: up to 36-fold
Eleutherosides: up to 200-fold
|American Journal of Clinical Nutrition|
They identified and measured the concentration of marker compounds by using HPLC and liquid chromatography-tandem mass spectrometry.
25 commercial ginseng preparations from the genera Panax or Eleutherococcus were obtained from a local health food store. These were analyzed for 7 ginsenosides (marker compounds for Panax species, which include Asian and American ginseng) and 2 eleutherosides (marker compounds for Eleutherococcus senticosus, also known as Siberian ginseng).
All plant products were correctly identified by botanical plant species (i.e. Panax species or E. senticosus).
However, concentrations of marker compounds were found to differ significantly from labeled amounts.
There was also significant product-to-product variability. Concentrations of ginsenosides varied by 15- and 36-fold in capsules and liquids, respectively. Concentrations of eleutherosides varied by 43- and 200-fold, respectively.
Although a systematic search for adulterants was not conducted, review of the HPLC and liquid chromatography-tandem mass spectrometry data suggest that no substances other than ginsenosides or eleutherosides were extracted from the plant material.
Researcher Martha R. Harkey concluded on behalf of fellow authors, "Our data suggest that US ginseng products are correctly labeled as to plant genus.
"However, variability in concentrations of marker compounds suggests that standardization may be necessary for quality assurance. In addition, characterization of herbal products should be considered in the design and evaluation of studies on herbal products."