Rare triterpene glycoside of ginseng (ginsenoside malonyl-Rg1) detected in plant cell suspension culture of Panax japonicus var. repens

This paper reports for the first time about the detection and identification of ginsenoside malonyl-Rg1 (the rare 20(S)-protopanaxatriol-type ginsenoside) in the biomass of plant cell suspension culture of Japanese ginseng (Panax japonicus C.A. Mey. var. repens). Ginsenosides were analyzed by means of high-performance liquid chromatography/electrospray ionization mass spectrometry (HPLC-ESI-MS) in positive-ion mode. Malonyl-Rg1 was identified as a result of interpretation of MS spectra obtained upon fragmentation of protonated molecular ion ([M + H]+) of this compound in an ionization source. Chromatographic analysis and MS spectra showed that the cells of P. japonicus var. repens cultivated in vitro contain several isomers of malonyl-Rg1. Thus, we ascertained for the first time that, in addition to malonyl ginsenosides of 20(S)-protopanaxadiol group, the plant cell culture of ginseng P. japonicus var. repens can accumulate glycosides of 20(S)-protopanaxatriol group acylated with a malonic acid residue. The obtained results showed that, in the cells of ginseng cultivated in vitro for a long time (for 10 years and more), the assortment of secondary metabolites (ginsenosides) may be as wide as in intact plants.