Production of ginseng saponins: elicitation strategy and signal transductions.

Ginseng is one of the most important plants in oriental medicine. The pharmacological effects of this medicinal herb are mostly correlated to the major bioactive triterpene saponin, called ginsenoside. Due to the long cultivation period of ginseng and increased ginsenoside level in aged root, we need to develop strategies to increase ginseng productivity in cell and tissue culture in a faster way. Elicitation is already considered to improve the yield of this valuable secondary metabolite; especially, different types, timings, and durations of elicitation could affect the ginsenoside production and heterogeneity. Activation of ginsenoside biosynthetic genes and ginsenoside accumulation mediated by elicitor-induced signaling molecules would be helpful for commercial production of individual ginsenosides. Jasmonic acid is the well-known signaling molecule which mainly involved in ginsenoside accumulation. Ca(2+) spiking and reactive oxygen species, nitric oxide, and ethylene production are other messengers which mediate production of ginsenoside. This review highlights the elicitation strategies for production of the ginsenoside based on the principle of putative signal transduction pathways.