Pharmacological evaluation for anti-asthmatic and anti-inflammatory potential of Woodfordia fruticosa flower extracts

Abstract Context: Woodfordia fruticosa Kurz. (Lythraceae) flowers are ethnopharmacologically acclaimed in the Indian medicinal system to treat asthma. Objective: To evaluate W. fruticosa flower extracts for anti-asthmatic effect. Materials and methods: Ethyl acetate, acetone, methanol, and hydro-alcohol extracts of W. fruticosa flowers were obtained successively and standardized. Ability of extracts to stabilize free radicals and compound-48/80-induced mast cell degranulation was evaluated. In vitro anti-inflammatory potential of extracts at 100 and 200 µg/ml by membrane stabilization and in vivo inhibition of rat paw edema up to 5 h (100 and 200 mg/ml; p.o.) was evaluated. In vitro bronchorelaxant effect was examined against histamine- and acetylcholine (1 µg/ml; independently)-induced guinea pig tracheal contraction. Extracts were evaluated for bronchoprotection (in vivo) ability against 0.1% histamine- and 2% acetylcholine-induced bronchospasm in guinea pigs at 100 and 200 mg/ml; p.o. Results: Standardization studies revealed that the methanol extract exhibited highest polyphenolic (62.66 GAE), and flavonoid (6.32 RE) content and HPLC fingerprinting confirmed the presence of gallic acid (Rt 1.383). IC50 values for DPPH scavenging and metal chelation by the methanol extract were 40.42 and 31.50 µg/ml. Methanol and ethyl acetate extracts at 100 µg/ml exhibited 06.52 and 07.12% of histamine release. Methanol, ethyl acetate, and hydro alcohol extracts at 200 mg/kg demonstrated 32.73, 29.83, 26.75% and 32.46, 9.38, 26.75% inhibition of egg albumin and carrageenan-induced inflammation, respectively. Methanol extract exhibited 100% bronchorelaxation and 48.83% bronchoprotection. Conclusion: Woodfordia fruticosa flower (WFF) extracts exhibited anti-asthmatic effect by demonstrating bronchoprotection, bronchorelaxation, anti-inflammatory, antioxidant, and mast cell stabilization ability.