Natural oils as emulsifying agent in the eco-friendly preparation of nano ZnO and their catalytic evaluation in the synthesis of 1,8-dioxo-octahydroxanthene derivatives with anti-inflammatory activity: In vitro, docking validation, and dft calculations

In the present work, bio-based ZnO nanoparticles were prepared using environmentally friendly methods. FTIR, XRD, and TEM illustrated the chemical structure of the prepared NPs. The nano ZnO was used as a catalyst to prepare xanthene compounds in one-step reactions by mixing two moles of dimedone and aromatic aldehyde under solvent-free conditions at 60-70 oC. After the specified time for the completion of the reaction, the products were separated and their structural forms were confirmed using IR, NMR and MS. The prepared xanthene derivative compounds undergo biological evaluation as COX1, COX2 and 5-LOX inhibitors. For example, it was noticed that ligand 6 inhibited the activities of COX-1 and COX-2 by 77.28±0.18 and 79.53±0.18 %, respectively. Compared to the standard indomethacin (a nonsteroidal anti-inflammatory drug), which inhibited the activities of COX-1 and COX-2 by 85.20±0.01 and 87.35±0.01 %, respectively. Also, ligand 6 presented the lowest IC50 values (5.96±0.04, 5.27±0.02 and 7.77±0.03 mg/mL, respectively) against COX-1, COX-2 and 5-LOX enzymes. Based on the data obtained from DFT (density functional theory) calculations, docking studies, and biological evaluations as inhibitors of COX-1, COX-2, and 5-LOX enzymes, it was determined that four derivatives (4, 6, 7, and 10) have potential for in vivo anti-inflammatory testing. KEY WORDS: Zinc oxide, Xanthene, Nanoparticles, Anti-inflammatory, DFT Bull. Chem. Soc. Ethiop. 2025, 39(9), 1779-1793. DOI: https://dx.doi.org/10.4314/bcse.v39i9.10