To quantify glycyrrhizin's effect on the humoral response, Raphael and Kuttan measured the number of anti-body producing cells and production of antibodies in the spleen, which increased in response to treatment with glycyrrhizin.

Santa Clara University

Licorice contains a saponin callled glycyrrhizin, which has antiviral and immunomodulatory responsibilities. 

The impact of licorice on the immune system

"The humoral immune system deals with antigens from pathogens that are freely circulating, or outside the infected cells. Antibodies produced by the B cells will bind to antigens, neutralizing them, or causing lysis (dissolution or destruction of cells by a lysin) or phagocytosis."


"Cellular immunity occurs inside infected cells and is mediated by T lymphocytes. The pathogen's antigens are expressed on the cell surface or on an antigen-presenting cell. Helper T cells release cytokines that help activated T cells bind to the infected cells’ MHC-antigen complex and differentiate the T cell into a cytotoxic T cell. The infected cell then undergoes lysis."

humoral immune response vs cellular immune response

Yang, F., Zhang, Y., Tariq, A., Jiang, X., Ahmed, Z., Zhihao, Z., Idrees, M., Azizullah, A., Adnan, M., & Bussmann, R. W. (2020). Food as medicine: A possible preventive measure against coronavirus disease (COVID-19). Phytotherapy research : PTR, 10.1002/ptr.6770. Advance online publication. https://doi.org/10.1002/ptr.6770

Food as medicine: A possible preventive measure against coronavirus disease (COVID-19)

The effect of glycyrrhizic acid on the humoral immune response in mice

It was found that white blood cell count  increased in mice treated with glycyrrhizic acid. 

The impact of glycyrrhizic acid on the white blood cells of mice

Taking licorice for a prolonged period of time can result in harmful effects, and those considering taking licorice to strengthen their immune system should consult their doctors first. Less side effects have been reported with licorice that is taken orally compared to intravenously or intraperitoneally. For certain groups of people, even a small amount of licorice can be harmful. 

Harmful side effects of licorice  

In a clinical trial by Cinatl et al., glycyrrhizin was tested on patients in a hospital in Germany who were infected with SARS-CoV. Glycyrrhizin was he most effective compound tested that inhibited SARS-CoV replication. Glycyrrhizin had a selectivity index of 67. It inhibited replication, adsorption and penetration of the virus.

Glycyrrhizin’s effect on vero cells that were  infected with SARS-CoV

Similar to SARS-CoV-2, influenza A virus (H5N1) is a viral respiratory disease that affects the lungs. Glycyrrhizin can reduce H5N1’s ability to affect IL-6 and chemokine production, and it also blocked DNA binding of the virus. For this reason, glycyrrrhizin could be a very powerful antiviral agent that should be considered for the prevention of SARS-CoV-2 infection.

Glycyrrhizin’s effect on the influenza A virus (H5N1)

These are two methods of processing and presenting antigens to human body.

Nanocarriers need to be degraded for encapsulated antigens to trigger cellular immune response, while the surface displayed antigens primarily lead to humoral immune response. 

encapsulated antigen vs surface displayed antigens

When applied to human monocyte cultures, green tea extract resulted in an increase in neopterin, a potential marker for the activation of cell-mediated immunity. 

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