Anti-inflammatory and anti-allergic potential of liquiritin extracted from Glycyrrhiza glabra L. in asthma management.

Abstract

Asthma is a chronic disease involving inflammation of the bronchi with a high global prevalence. The present study evaluated the effects of liquiritin extracted from Glycyrrhiza glabra L. on inflammation and immune dysregulation induced by ovalbumin (OVA)-induced allergic asthma in mice. Thirty-six albino mice were randomly divided into six groups: the negative control group, positive control group, reference group (methylprednisolone, 15 mg/kg i.p.), and the liquiritin treatment groups (LQ20: 20 mg/kg p.o., LQ40: 40 mg/kg p.o., LQ60: 60 mg/kg p.o.). The mice were sensitization with OVA on the 0th and 14th day, followed by intranasal OVA challenge from 21st to 27th days. The pulmonary edema (lung wet/dry ratio), hematological parameters (total leukocyte count [TLC], differential leukocyte counts [DLC], and bronchoalveolar lavage fluid [BALF]), histopathological alterations (hematoxylin and eosin and periodic acidic-Schiff stained), and mRNA expression of cytokines IL-4 and IL-5 by real-time qRT-PCR were evaluated. Liquiritin treatment significantly attenuated the pulmonary edema and histopathological features of airway inflammation. A significant decrease in TLC and DLC was observed in both blood and BALF samples compared with the positive control group. Furthermore, liquiritin significantly downregulated the mRNA expression IL-4 and IL-5, key Th2 cytokines implicated in the allergic airway inflammation. Collectively, this study demonstrated that liquiritin exerts potent anti-inflammatory and immune modulatory effects in allergic asthma, potentially via Th2-mediated cytokine signaling. Overall, this study highlighted the liquiritin as a promising candidate for the development of novel therapeutic interventions targeting airway inflammation and immune dysregulation in allergic asthma.