title: Glycyrrhizin alleviates experimental allergic asthma in mice.
abstract: Asthma is a chronic respiratory disease, the incidence of which is increasing globally. The existing therapy is inadequate and has many adverse effects. It needs a better therapeutic molecule preferably of natural origin, which has negligible or no adverse effects. In view of this, we evaluated Glycyrrhizin (GRZ), a major constituent of a plant Glycyrrhiza glabra, for its efficacy on asthmatic features in a mouse model of asthma. BALB/c mice were sensitized and challenged with ovalbumin (OVA) to develop the asthmatic features such as airway hyperresponsiveness: allergen induced airway constriction and airway hyperreactivity (AHR) to methacholine (MCh), and pulmonary inflammation. The mice were orally treated with GRZ (2.5, 5, 10 and 20 mg/kg) during or after OVA-sensitization and OVA-challenge to evaluate its protective or reversal effect, respectively on the above asthmatic features. The status of airway hyperresponsiveness was measured by monitoring specific airway conductance (SGaw) using a non-invasive method and the pulmonary inflammation was assessed by haematoxylin and eosin staining of lung sections. Several other parameters associated with asthma such as interleukin (IL)-4, IL-5 interferon-gamma (IFN-gamma), OVA-specific IgE, total IgG(2a) and cortisol were measured by ELISA. GRZ (5 mg/kg) markedly inhibited OVA-induced immediate airway constriction, AHR to MCh (p<0.01), lung inflammation, and infiltration of eosinophils in the peribronchial and perivascular areas. It prevented the reduction of IFN-gamma (p<0.02), and decreased IL-4 (p<0.05), IL-5 (p<0.05) and eosinophils (p<0.0002) in the BAL fluid. Also, it reduced OVA-specific IgE levels (p<0.01) and prevented the reduction of total IgG(2a) (p<0.01) in serum. We have also showed that it has no effect on serum cortisol levels. Our results demonstrate that GRZ alleviates asthmatic features in mice and it could be useful towards developing a better therapeutic molecule in the future.
authors.affiliation: Molecular Immunogenetics Laboratory, Institute of Genomics and Integrative Biology, Mall Road, Delhi-110007, India.
authors.forename: Arjun
authors.initials: A
authors.lastname: Ram
authors.forename: U
authors.initials: U
authors.lastname: Mabalirajan
authors.forename: Moumita
authors.initials: M
authors.lastname: Das
authors.forename: Indranil
authors.initials: I
authors.lastname: Bhattacharya
authors.forename: Amit K
authors.initials: AK
authors.lastname: Dinda
authors.forename: Sharad V
authors.initials: SV
authors.lastname: Gangal
authors.forename: Balaram
authors.initials: B
authors.lastname: Ghosh
mesh_terms: D000485:Allergens / Q000008:administration & dosage*; D000818:Animals; D018927:Anti-Asthmatic Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000008:administration & dosage; D001249:Asthma / Q000188:drug therapy* / Q000276:immunology / Q000473:pathology; D004195:Disease Models, Animal; D019695:Glycyrrhizic Acid / Q000008:administration & dosage / Q000627:therapeutic use*; D006854:Hydrocortisone / Q000097:blood; D007073:Immunoglobulin E / Q000097:blood; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D010047:Ovalbumin / Q000008:administration & dosage / Q000037:antagonists & inhibitors
chemical_list: D000485:Allergens; D018927:Anti-Asthmatic Agents; D000894:Anti-Inflammatory Agents, Non-Steroidal; D007073:Immunoglobulin E; D019695:Glycyrrhizic Acid; D010047:Ovalbumin; D006854:Hydrocortisone