Immunomodulator & Glycyrrhiza glabra (Licorice or Sweetwoods)

Immunomodulator

Immunomodulation is a key issue in tissue homeostasis for the physiological stability of organisms+. The function and efficiency of the immune system are influenced by various exogenous and endogenous factors resulting in either immunosuppression or immunostimulation. 

Several agents possessing an activity to normalize or modulate pathophysiological processes are known as  immunomodulator.

 The biomolecules of synthetic or biological origin capable of modulating, suppressing and stimulating any components of adaptive or innate immunity are called as immunomodulators, immunorestoratives, immunoaugmentors, or biological response modifier.

Immunomodulators are generally categorized into immunoadjuvants, immunostimulants, and immunosuppressants in clinical practice. Immunoadjuvants are specific immune stimulators which enhance the efficacy of vaccine. Agents that activate or induce the mediators or components of immune system are called as immunostimulants. The resistance against autoimmunity, cancer, allergy, and infection is enhanced by immunostimulants. On the other hand, immunosuppressants are the molecules that inhibit the immune system, can be used to control the pathological immune reaction subsequent to organ transplantation.[1]

In the classical examples of immunomodulators, many plant extracts can act as botanical adjuvants for conjugation with vaccines, with high level of usefulness in human and animal medicine. The extracts of  Tinospora cordifolia have been used as an immunomodulator, along with chloroquine, for the treatment of hyper-reactive malarial splenomegaly with promising results.

Figure 1: The immunostimulant and immunomodulatory activity of herbs

Plants and Herbs with Immunomodulatory Properties and Applications

 Glycyrrhiza glabra (Licorice or Sweetwoods)

Glycyrrhiza glabra is native to Central Asia and the Mediterranean region. The roots are commonly known as licorice or sweetwoods. The root extract of this plant has been used historically in Egyptian, Chinese, Indian, and Greek medicine as carminative and expectorant. , it is described in Ayurveda as Rasayana against throat infections.

The major components of licorice are triterpene saponins, flavonoids, and pectins, which are responsible for its pharmacological activity . Glycyrrhizin (GL), contains a triterpene compound responsible for the sweetness of its root; the flavonoid compound, isoliquiritin, is responsible for the yellow color of licorice.

 Licorice contains compounds that display steroid-like anti-inflammatory activity by the inhibition of phospholipase A2 and they interfere with platelet aggregation.

The anti-inflammatory and hepatoprotective function of licorice reportedly increased the production of NF-κB and IL-10 by GL. The Bcl-2/Bax family of genes, which are the regulatory factors for apoptosis, were found to be modulated by the components of GL root.

Licorice contains two chemical components, isoliquiritigenin and naringenin, which have been reported to enhance regulatory T cells and therefore may be cause of the anti-inflammatory properties and efficacy against autoimmune diseases.

The purified saponins from this plant used in ISCOM preparation significantly enhanced the immune response of broiler chickens against Eimeria tenella.

 

G. uralensis (Chinese licorice) was reported to regulate the cytokine IL-7, which is involved in immune cell proliferation and maturation, and can thus act as anticancer agent.

Licorice root powder, capsules, or slices are available for purchase and known for their multiple applications.

it is used for stomach disorders, sore throats, snake bites, scorpion bites, and food poisoning.

The root of Glycyrrhiza glabra possesses multiple properties; it can be used as a sweet refrigerant, aphrodisiac, alexipharmic, alterant, emetic, diuretic, demulcent, expectorant, emmenagogue, and intellect promoting. Furthermore, successful use in bronchitis, cough, cephalalgia, fever gastralgia, gastric ulcers, hyperdipsia, ophthalmopathy, pharyngodynia, skin diseases, cuts, and wounds has been demonstrated.

Recently, several other bioactive chemicals have been isolated from the plant, including isoprenylated phenolics and echinatin, which confers the hepatoprotective properties . Carbenoxolone (18-β glycerrhetinic acid and hydrogen succinate), an analog of glycerrhetinic acid, is used in the treatment of certain alimentary tract ulcerative conditions, such as peptic ulcer fig 1.2.[2]

 

Fig 1.2 : Chemical Structure of Carbenoxolone

 

 

Fig  1.3 : immunomodulatory effects of Glycyrrhiza glabra

REFERENCE

[1]  Ibrahim Jantan, Waqas Ahmad, and Syed Nasir Abbas Bukhari,” Plant-derived immunomodulators: an insight on their preclinical evaluation and clinical trials”  Front Plant Sci. 2018 August 13; 9: 1178

[2]  Ruchi Tiwari, Shyma K Latheef, Ishtiaq Ahmed,” Herbal Immunomodulators - A Remedial Panacea for Designing and Developing Effective Drugs and Medicines: Current Scenario and Future Prospects”