The Review of in Vitro and in Vivo Studies over the Glycyrrhizic Acid as Natural Remedy Option for Treatment of Allergic Asthma.

Allergic asthma is the most common type of allergy which have become increasingly prevalent in all around the world. Airway eosinophilic inflammation is a major feature of allergic asthma. Glycyrrhiza uralensis (licorice) is one of the regular herbs in traditional Chinese medicine (TCM) as it has many effects on the immune system such as anti-inflammatory and immune regulatory activity; antiviral and antitumor effects. This review focuses on the "licorice" components, mainly glycyrrhizic acid (GA) and derivatives structure that evaluate its effects on the allergic asthma. We performed searching articles in Pubmed, Web of Science, and Scopus data bank from 1990 to 2017. The search syntax were: "glycyrrhizin" OR " glycyrrhizic acid" OR " glycyrrhizinic acid" OR" glycyrrhiza glabra" OR " liquorice root" OR "G. glabra" OR "glycyrrhizic Acid" AND "allergic asthma" OR "bronchial asthma" OR "asthma, bronchial" OR "airway hyper-responsiveness" OR "airway inflammation". Several molecular mechanisms and inflammatory mediators may possibly be responsible for efficacy of glycyrrhizin. Some in vitro studies indicated to the fact that possible mechanisms of anti-inflammatory effects could be through reduction of pro-inflammatory mediator's synthesis that motivates eosinophil, basophils and mast cells to release cytokines for the differentiation of T helper cells into Th2 cells to secrete interleukins. Furthermore, some transcription factors such as NF-κB, STAT6 and HDAC2 go between modulations of anti-asthmatic effects. The last but not the least it can be said that glycyrrhizin is potentially a good herbal drug with the lower most adverse effects for asthma treatment.