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

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 (R_t 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.