## 2 Results
### Effect of Carvacrol Treatment on Ginsenoside Production in Hairy Roots of P. quinquefolium
Their levels were reduced in comparison to those of the control samples, regardless of carvacrol concentrations and the time of exposure. After 24 h with 5 uM of carvacrol, they reduced by about 10%. The amount of both saponins decreased to approximately 50% of the value noted for the control, with an increase in the carvacrol concentration, and then remained constant (except for 500 uM of carvacrol). The lowest amount of Rb1 and Rd was noted for 500 uM of carvacrol. The accumulation of Rb3 was also inhibited, except for 5 uM of carvacrol and 24 h of elicitation. Then, its level was comparable to that observed in untreated samples. Moreover, it was noticed that after reduction to a specific level, the content of individual protopanaxadiol derivatives was maintained at a similar level for different concentrations of carvacrol, regardless of the time of elicitation (except for a concentration of carvacrol of 5 uM and 24 h of exposure). In contrast, the level of Re saponins increased after carvacrol treatment. Regardless of the time of elicitation, the amount gradually enhanced with the carvacrol concentration, achieving its maximum level (11.34 mg\(\cdot\)g\({}^{-1}\) d.w.; 72 h of elicitation) at 100 uM, and it was 7.72-fold higher in comparison to the control samples. The improved accumulation of the Rg1 metabolite was noted after 72 h of elicitation at 5-250 uM of carvacrol. Initially, its content increased by about 18.65% (5 uM). Its highest level was noted at 10-100 uM of carvacrol, i.e., 0.973-1.016 mg\(\cdot\)g\({}^{-1}\) d.w. (approximately a 1.5-1.57-fold increase in comparison to the control). A higher concentration of carvacrol decreased the Rg1 level. Interesting results were obtained for the Rg2 metabolite. It was observed that the biosynthesis of Rg2 was induced after carvacrol treatment. Its maximum level (0.918 mg\(\cdot\)g\({}^{-1}\) d.w) was for 10 uM of carvacrol, after a longer time of elicitation (72 h). This compound was undetected in untreated samples. The yield of ginseng biosynthesis was also characterized by a productivity evaluation of the studied cultures (Figure 11). The value of this parameter was 3.97 mg\(\cdot\)L\({}^{-1}\)-day\({}^{-1}\) in the control culture for all studied saponins. Their highest productivity was 5.74 mg\(\cdot\)L\({}^{-1}\)-day  
Figure 5: The ratio of total content of Rb-group ginsenosides/total content of Rg-group ginsenosides (RbG/RgG) in hairy root cultures of _P. quinquefolium_. (100 \(\mu\)M of carvacrol and 72 h of elicitation). Among the individual studied metabolites, saponin Re showed the most enhanced productivity (an increase from 0.419 mg.L\({}^{-1}\)-day\({}^{-1}\) in the control to 3.236 mg.L\({}^{-1}\)-day\({}^{-1}\) after carvacrol treatment with a 100 \(\mu\)M concentration and 72 h of elicitation). Figures 7 and 2 show the productivity expressed as levels above or below the productivity in the control. An analysis of the obtained results showed that metabolites, being protopanaxadiol derivatives, respond to carvacrol treatment by reducing their productivity below the level determined for the control (except Rc and Rb2, with 24 h of exposure to 5 \(\mu\)M of carvacrol). Moreover, it was noticed that carvacrol treatment resulted in the high stimulation of Re biosynthesis and the induction of Rg2 production. The weakest influence of carvacrol was observed for the productivity of the Rg1 compound. In addition, Figure 6 demonstrates similar changes in the profile productivity of the Rg group and saponin Re and shows that they depend on the carvacrol concentration and the time of exposure. Figure 6: The effect of carvacrol treatment on the accumulation of individual ginsenosides in hairy roots of _P. quinquefolium_, “c” means control sample. Figure 7: Ginsenoside productivity expressed as levels above (blue color) or below (red color) productivity in the control in hairy roots of _P. quinquefolium_.