Spectral signatures and biological efficacy of Limonia acidissima L. bark extracts in combating oxidative stress and inflammation

Background: Medicinal plants are valuable reservoirs of bioactive molecules that continue to serve as leads for modern drug discovery. Limonia acidissima L. (Rutaceae), traditionally valued for its therapeutic uses, remains underexplored with respect to its bark-derived phytoconstituents. Materials and Methods: The ethanolic bark extract of L. acidissima was analyzed using High-Performance Liquid Chromatography (HPLC), Fourier Transform Infrared Spectroscopy (FT-IR), UV-Visible spectroscopy, and Gas Chromatography-Mass Spectrometry (GC-MS) to characterize phytochemical diversity. Antioxidant potential was assessed using the DPPH radical scavenging assay, while anti-inflammatory activity was evaluated through goat red blood cell (GRBC) membrane stabilization. Additionally, molecular docking was performed against the MYST acetyltransferase domain (PDB: 6OIO) to explore phytochemical-protein interactions. Results: HPLC revealed 14 peaks between 200-700 nm, with the highest peak at 13.598 minutes. FT-IR confirmed functional groups such as alkyl halides, aromatics, alcohols, carboxylic acids, alkanes, and amines. UV-Vis spectra indicated absorption peaks ranging from 500 to 1100 nm, characteristic of alkaloids, flavonoids, and phenolic compounds, while GC-MS detected 20 major metabolites, including 2-methoxy-4-vinylphenol, isopsoralen, scopoletin, braylin, marmesin, visamminol, and squalene. The extract exhibited moderate antioxidant activity in the DPPH assay (IC₅₀ = 353.58 µg/mL) and 72% hemolysis inhibition in GRBC membrane stabilization at 1000 µg/mL, compared to 89% for acetylsalicylic acid. Docking studies revealed strong binding affinities of marmesin, braylin, and scopoletin, supporting their role in modulating inflammation pathways. Conclusion: The ethanolic bark extract of L. acidissima is rich in bioactive phytochemicals and exhibits appreciable antioxidant and anti-inflammatory potential. These findings validate its ethnomedicinal relevance and highlight its promise as a natural source of therapeutic agents.