Illicium verum extract exhibited anti-inflammatory action in rodents

Background: Illicium verum Hook. f. (Star anise) has been traditionally used for the treatment of abdominal colic, vomiting, pain, nervousness, insomnia and rheumatism. Objective: The present study was conducted to investigate the anti-inflammatory properties of Illicium verum extracts. Methods: Different extracts of I. verum (IV-Ext-1, IV-Ext-3 and IV-Ext-4) were screened for their anti-inflammatory potential using carrageenan-induced paw edema in mice. The mechanism of action was explored using paw edema tests (carrageenan, histamine, serotonin and prostaglandins) in rats and anti-oxidant activity (DPPH assay). Reverse phase HPLC was used for chemical characterization of extracts. Results: The IV-Ext-3 was found to be the most potent anti-inflammatory agent (38% inhibition) using carrageenan-induced paw edema. The anti-inflammatory effect was observed during both the initial (IC50: 260 mg/kg) and late phases (IC₅₀: 200 mg/kg). Similar IC₅₀ of 200 mg/kg was observed in both phases of histamine-induced paw edema. However, the extract failed to cause 50% inhibition in serotonin-induced edema (IC₂₅: 400 mg/kg) and was also ineffective against Prostaglandin- E2 induced edema. Furthermore, the IV-Ext-3 appeared to be an effective antioxidant (IC₅₀: 12 µg/ml). The HPLC chromatogram of IV-Ext-3 showed the presence of anti-inflammatory constituents such as shikimic acid (1.6%) and anethole (0.25%), 3, 4-dihydroxybenzoic acid (0.003%) and p-hydroxy methyl benzoate (0.117%) along with some polar hydroxyl derivatives of benzoic acids. Conclusion: Among all the extracts of I. verum, IV-Ext-3 was found to be the most effective antiinflammatory agent which can be attributed to multiple anti-inflammatory constituents, antihistamine and antioxidant potentials.