Elicitation in plants refers to the addition of specific molecules that provoke a stress response, which can, in turn increase secondary metabolites. A previous study of the effects of elicitation on cell suspension of Cannabis sativa found that secondary metabolites were impacted by both biotic and abiotic elicitors. [1] However, this study focused on the cannabinoid tetrahydrocannabinolic acid (THCA). Cannabinoids are primarily found in the trichomes which are not impacted by elicitation.
In a study by Gabotti et al., it was found that the elicitation strategy of methyl jasmonate (MeJA) combined with precursor feeding of tyrosine (Tyr) increased phenylalanine ammonia-lyase (PAL) and tyrosine aminotransferase (TAT). [2] The gene expression for these enzymes was increased by elicitation. However, there was variation in the enhancement between the two enzymes responses based on the number of days of elicitation (one or four days).
While the MeJA slowed growth rate compared to other methods, it enhanced phenolic accumulation by approximately 52%. The precursor feeding of tyrosine was found to increase the phenolics by 82%, providing a 20% increase on top of the MeJA alone.
Total phenolic acid accumulation was linked with the secondary metabolic pathways impacted by elicitation. This was investigated by nuclear magnetic resonance spectroscopy to find primary differences.
The intensity of two aromatics, specifically 4-hydroxyphenylpyruvate (4-HPP) and 4-hydroxyphenyllactate (4-HPL), more than doubled with a 2.84- and 2.65-fold increases, respectively. “The elicitation treatment also produced a 3.3-fold increase in tyrosol and a 1.77-fold increase in tyramine content,” the study authors wrote. This was the first time 4-HPP was identified in a hemp cell suspension.
Antioxidant activity was tested on an ex vivo model of human erythrocytes placed in oxidative stress. The elicited cells provided stronger protection against free radicals with an 80% increase in antioxidant activity in four days.
This study confirmed the study by Peč et al that the antioxidant metabolite tyrosol, often found in olive oil, could be produced by hemp cells. [3] Peč et al found that elicitation with jasmonic acid increased tyrosol, while Gabotti et al found that their use of MeJA + Tyr had a similar accumulated concentration. [2]
The findings of this study show that hemp cell extracts could be used as a source of natural antioxidants for applications in pesticides, food preservation, pharmaceuticals, nutraceuticals, and more. Specifically, there is potential for use in food preservation as the safety of synthetic preservatives is coming into question. [2]
References
1- Flores-Sanchez IJ, et al. Elicitation studies in cell suspension cultures of Cannabis sativa L. Journal of Biotechnology. 2009;143(2):157-68. Doi: 10.1016/j.jbiotec.2009.05.006. Times cited=15. Journal impact factor=3.163
2- Gabotti D, et al. Cell suspension of Cannabis sativa (var. Furtura): Effect of elicitation on metabolite content and antioxidant activity. Molecules. 2019;24(22):4056. doi: 10.3390/molecules24224056. Times cited=6. Journal impact factor=4.411
3- Peč J, et al. Metabolic analysis of elicited cell suspension cultures of Cannabis sativa L. by 1H-NMR spectroscopy. Biotechnology Letters. 2010;32:935–941. Times cited=14. Journal impact factor=1.977
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