Differences in the chemical composition of Panax ginseng roots infected with red rust

Ginseng rusty root (GRR) is a commonly occurring disease that affects the continuous farming and economic value of mountain cultivated ginseng (MCG). Previous studies have demonstrated a generally smaller level of total ginsenoside in GRR tissue, but differences in individual ginsenosides or changes between rusty and healthy MCG with a higher age have not been investigated.

This research aimed to identify differences in the chemical components in the roots of rusty compared with healthy MCG harvested at 20-years of age.

Differences between rusty and healthy MCG roots in individual ginsenosides were evaluated using a non-targeted metabonomic-based ultrahigh-performance liquid chromatography quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS) technique. Chemical markers and the principal constituents were then quantified by ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). Furthermore, total ginsenosides, total polysaccharides, and the elemental composition were evaluated separately using spectrophotometry and inductively coupled plasma optical emission spectrometer (ICP-OES).

There was no significant difference in the levels of total ginsenosides or total polysaccharides between the rusty and healthy groups. However, the concentrations of pivotal individual ginsenosides, including ginsenoside Rc, ginsenoside Ro, and ginsenoside Rd were significantly lower in the rusty group. In addition, concentrations of Fe and Al were higher in the rusty group compared with the healthy group.

The results suggest that GRR affects the synthesis of ginsenosides of 20-year-old MCG, which further establishes reference data and the basis for exploration of the mechanisms causing metabolic changes in ginseng resulting from GRR.