Bioassay guided fractionation and identification of active anti-inflammatory constituent from Delonix elata flowers using RAW 264.7 cells

Abstract

Context: Delonix elata (L.) Gamble (Fabaceae) has been used in the Indian traditional medicine system to treat rheumatism and inflammation.

Aim: To assess the anti-inflammatory effect of Delonix elata flowers and to isolate the active principle.

Materials and methods: The prompt anti-inflammatory constituent was isolated from Delonix elata flower extracts using bioassay guided fractionation in liposaccharide (LPS) stimulated RAW 264.7 macrophage cell line. The anti-inflammatory activity of extracts/fractions/sub-fractions/compounds (10, 25, and 50 µg/ml) was evaluated by estimating the levels of nitric oxide (NO), TNF-α, and IL-1β after 24 h of LPS induction (1 μg/ml). The isolated active compound was subjected to NMR, IR, and UV analyses for structure determination.

Results: In an attempt to search for anti-inflammatory constituents, the active pure principle was isolated and crystallized as a white compound from Delonix elata flowers methanol extract. This active compound (50 µg/ml) decreased the release of inflammatory mediators levels such as NO (0.263 ± 0.03 µM), TNFα (160.20 ± 17.57 pg/ml), and IL-1β (285.79 ± 15.16 pg/ml) significantly (p < 0.05); when compared to the levels of NO (0.774 ± 0.08 µM), TNFα (501.71 ± 25.14 pg/ml), and IL-1β (712.68 ± 52.25 pg/ml) from LPS-stimulated macrophage cells. The active compound was confirmed as hesperidin with NMR, IR, and UV spectroscopy data. This is the first report of this compound from Delonix elata flowers.

Conclusion: The findings of the study support the traditional use of Delonix elata flowers to treat inflammation.

• Hesperidin
• inflammation
• Macrophages
• traditional plant

Acknowledgements

The authors are thankful to Mr. S. Mutheeswaran, Entomology Research Institute, Loyola College, Chennai for his help in plant collection.

Declaration of interest

The authors report no conflict of interest. The authors are thankful to Indian Council of Medical Research (Ministry of Health and Family Welfare), New Delhi, for financial support (Sanction number: 59/33/2009/BMS/TRM).