In vitro anti-inflammatory and antioxidant activities of Delonix regia (Bojer Ex Hook.) Raf. leaf and stem

Inflammation and oxidative stress are closely connected and play crucial roles in the development of diseases. Several synthetic drugs have been employed to treat these conditions, but not without side effects. Delonix regia has been used traditionally to treat inflammation and other health problems. Hence, this study validated the in vitro anti-inflammatory and antioxidant potential of leaf and stem extracts and fractions of D. regia. The dried and pulverized leaves and stems were extracted with methanol at room temperature, and the extracts were screened for secondary metabolites. The anti-inflammatory activity was determined using the membrane stabilising assay, and antioxidant activity was determined using DPPH, ferric ion reducing antioxidant power (FRAP), and total antioxidant capacity (TAC) assays. FT-IR was used to identify the functional groups in the crude extracts. GC?MS was used to analyse the compounds in the stem fraction. Phytochemical screening of the crude extracts revealed the presence of saponins, tannins, flavonoids, cardiac glycosides, terpenoids, alkaloids, and phenols. The leaf extract showed a greater membrane stabilizing activity (47.77%) compared to the stem extract (40.46%) and Indomethacin, the standard drug (41.46%). The DPPH, TAC content, and reducing power ability were concentration dependent. The stem extract presented a high antioxidant capacity. Functional groups such as alcohols, amines, alkanes, aromatic, nitro compounds, and alkyl and aryl halides were identified and common to both extracts. The leaf and stem extracts possess significant anti-inflammatory and antioxidant properties. Further studies on the toxicological profile, isolation, and characterization of bioactive compounds are recommended. Key words: Delonix regia, Leaf and stem extracts, Anti-inflammatory and antioxidant activities.