Inflammation Modulating Activity of the Hydroethanol Stem Bark Extract of Bombax costatum in Murine Models

Bombax costatum (Bombacaceae) is traditionally used as a decoction of the leaves, stem, and root to treat headaches, fever, and oedema that may be associated with inflammatory conditions. Thus, the aim of this study was to evaluate the effect of 70%^v/_v ethanolic extract of the stem bark of Bombax costatum on acute and chronic inflammation. The effect of Bombax costatum extract (10, 50, 100 mg kg^-1, p.o) was studied in prostaglandin E₂-induced paw oedema in Sprague-Dawley rats (n = 5). Subsequently, the effect of the extract on clonidine and haloperidol-induced catalepsy was also investigated in ICR mice (n = 5). Finally, the ability of the extract to inhibit chronic inflammation was studied using a rat adjuvant-induced arthritis model. Pre-emptive and therapeutic administration of the extract at all doses significantly suppressed the formation of oedema following prostaglandin E ₂ administration. As a measure of indirect antihistaminic effect, treatment with the extract suppressed clonidine-induced catalepsy but not haloperidol-induced catalepsy. Moreover, Bombax costatum extract significantly inhibited joint inflammation and damage following injection of complete Freund's adjuvant. Treatment with the extract also inhibited the onset of polyarthritis; thus, suppressing the systemic spread of joint inflammation from ipsilateral limbs to contralateral limbs. In conclusion, the hydroethanol extract of the stem bark of Bombax costatum inhibits both acute and chronic inflammation.