Determination of ginsenosides Rb1, Rc, and Re in different dosage forms of ginseng by negative ion electrospray liquid chromatography-mass spectrometry.

A method based on high-performance liquid chromatography (HPLC) and negative ion electrospray mass spectrometry (LC-MS) has been used to determine ginsenosides Rb1, Rc, and Re in six different samples of ginseng. These included a liquid extract, capsules, tea bags, and an instant tea. It was found that four of the six samples had detectable levels of at least one of the ginsenosides. The liquid extract, capsules, instant tea, and tea bags labeled ginseng had ginsenosides. The labels on the two samples that did not have ginsenosides indicated that they were a mixture of green tea, licorice, and ginseng. Also, 13C NMR was used to identify the types of complex carbohydrates present in the samples. One of the samples of tea bags had none of the ginsenosides, but did have complex carbohydrates found in most of the other samples. The instant tea had all three ginsenosides, but had no complex carbohydrates, only sucrose. The amounts of ginsenosides found in standard doses from six different sources of ginseng varied considerably. It was found that steeping a tea bag for a longer time than that recommended on the label produced a larger recovery of ginsenosides and that reusing a tea bag produced even higher recoveries.