Evaluation of analgesic activity of ethanolic leaf extract of Acacia auriculiformis A. Cunn. ex Benth and its biofraction: Experimental and computational approach

Objectives: The study aimed at evaluating the analgesic potential of the ethanolic leaf extract of Acacia auriculiformis (EEAA) and its acetone-enriched A. auriculiformis (AEAA) fraction, using experimental and computational approaches. Materials and Methods: The ethanolic leaf extract and its bioactive fraction were prepared using the reflux method. The antioxidant potential of EEAA and AEAA was assessed using in vitro 2,2-diphenyl-1-picrylhydrazyl (DPPH), nitric oxide and hydrogen peroxide scavenging assays, while the analgesic activity was evaluated using a hot plate analgesiometer and tail immersion methods in Wistar albino rats at a dose of 200 mg/Kg and 400 mg/Kg over a period of 7 days. The probable phytoconstituents in EEAA and AEAA were analysed using liquid chromatography–mass spectrometry (LC-MS) analysis, and the identified constituents were docked in silico using the Kappa opioid receptor (KOR). Statistical analysis was performed using one-way analysis of variance followed by Dunnett’s test. Results: AEAA demonstrated superior-free radical scavenging capacity in all three assays. Both EEAA and AEAA exhibited dose-dependent analgesic effects, with AEAA at 400 mg/Kg exhibiting a statistically significant increase in activity ( p < 0.05) in both the analgesic models. Furthermore, LC-MS analysis revealed the presence of various phytoconstituents. The selected phytoconstituents, when docked with KOR in silico demonstrated strong binding affinities, indicating a possible mechanism underlying their analgesic action. Conclusion: The findings of the study highlight the promising therapeutic analgesic potential of A. auriculiformis , especially its AEAA fraction, and warrant further investigation to isolate and characterise the bioactive constituents.