Anti-inflammatory Activity of Delonix elata (L.) Gamble

Objectives: To investigate anti-inflammatory activity of Delonix elata (D.elata) leaf, by carrageenan induced paw edema and cotton pellet granuloma models, along with the antioxidant potential underpinning its role as traditional medicine for joint disorders. Materials and methods: Methanol extract and its, ethyl acetate soluble and insoluble daughter fractions were evaluated for anti-inflammatory activity. Rats were divided into seven groups (n=6), including control and standard. Oral doses of methanol extract (100, 200 and 300mg/kg) and its daughter fractions (300mg/kg) were given to animals after carrageenan challenge. The best performing methanol extract was forwarded for cotton-pellet induced granuloma model. The same was also subjected to antioxidant assays like DPPH free radical scavenging activity, reducing power assay and nitric oxide scavenging activity. Moreover, isolation and HPTLC quantification of a marker compound was also attended from methanol extract derived ethyl acetate fraction. Results: In comparison to control, methanol extract of D. elata leaf at 300 mg/kg showed significant reduction in area under curve of rat paw edema in the later phases of inflammation (45.83%), which was comparable to that of standard (valdecoxib, 33.525%). The extract was also effective in producing 28.125% inhibition of granuloma formation which was comparable to that of standard (23.88%). Apart from nitric oxide scavenging assay (IC₅₀ 157.08μg/ml), the activity of methanol extract in other assays were not as significant as the respective standard drugs. Of the ethyl acetate soluble and insoluble fractions evaluated, both showed marginal reduction in paw edema. From the ethyl acetate fraction, luteolin was isolated as a marker compound and quantified by HPTLC. Conclusion: Methanol extract of D. elata leaf was found to be active in the last phase of paw edema at 300 mg/kg, compared to other doses and fractions. At the same dose it was found to have potent antioxidant capacity, which may play its role in reducing inflammation. The claims regarding anti-inflammatory activity of D. elata leaf can be considered valid as explicated by its methanol extract.