Objective: Inflammation and oxidative stress are important factors in the pathogenesis of diabetes. This study was carried out to determine the effect of licorice (Glycyrrhiza glabra) hydroalcoholic extract (Li) and its bioactive compound, glycyrrhizic acid (GA) on liver function markers, inflammatory factors, oxidative stress, and apoptosis regulators in diabetic rats.
Materials and methods: Thirty-six male Wistar rats were randomly divided into 6 groups: diabetic rats, diabetic rats treated with Li (50 and 100 mg/kg), diabetic rats treated with GA (50 and 100 mg/kg), diabetic rats treated with Li and GA, and healthy rats, for 30 days. Administration was done by intraperitoneal injection. Alloxan (240 mg/kg, intraperitoneal injection) was used to induce diabetes. Serum levels of alkaline phosphatase (ALP), alanine transaminase (ALT), aspartate aminotransferase (AST), gamma-glutamyl transferase (GGT), C-reactive protein (CRP), tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, IL-6, malondialdehyde (MDA), 8-hydroxy-2'-deoxyguanosine (8-OHdG), glutathione peroxidase (GPX), and superoxide dismutase (SOD), as well as Bax and BCL2 proteins were measured. Data analysis was done with GraphPad Prism software.
Results: The diabetic control level of serum ALP, ALT, AST, GGT, CRP, TNF-α, IL-1β, IL-6, MDA, 8-OHdG, and Bax proteins was significantly higher compared with the treatment groups (p ≤ 0.001). The protein levels of GPX, SOD, and BCL2 were significantly up-regulated in the treatment groups compared to diabetic control groups (p ≤ 0.001). Most variables showed a better result with the 100 mg/kg GA for 30 days.
Conclusion: The present study showed the anti-inflammatory effects of the extract of the root of licorice and the active compound of it, GA, in ameliorating the diabetic-induced hepatic damage in rats.