Comparison of the ginsenoside composition of Asian ginseng (Panax ginseng) and American ginseng (Panax quinquefolius L.) and their transformation pathways

Ginseng is a slow-growing perennial herbaceous plant, belonging to the genus Panax of the family Araliaceae. As the two most popular species, Asian ginseng (Panax ginseng) and American ginseng (Panax quinquefolius L.) have been commonly used for their medicinal properties. Ginseng saponins, known as ginsenosides, the major and unique components of ginseng, have attracted lots of interest. This comprehensive literature review aims at exploring differences in ginsenoside composition between Asian ginseng and American ginseng. From the years between 1963 to the middle of 2017, at least 196 ginsenosides were identified from the roots, leaves, stems, flower buds and fruits of Asian ginseng, and 99 ginsenosides were isolated from American ginseng. Among these saponins, 51 ginsenosides were found in both ginseng varieties. The chemical structures of ginsenosides were described and classified into seven subtypes based on the different skeleton structures. Some ginsenosides are artifacts of the extraction process. The possible biotransformation pathways of ginsenosides were reviewed, and some other interesting saponins were predicted to be potentially present in ginseng based on the biosynthesis pathway. This work will provide a comprehensive reference for the chemical compositions and transformations of ginseng.