Anti- inflammatory response of Zanthoxylum myriacanthum Wall. ex Hook.f. fruit extract

Background Zanthoxylum myriacanthum, known as Ma-khwaen, is widely used in Thai folk medicine and as a culinary spice. The whole fruits, including pericarp and seeds, extracted with 95% ethanol has anti-inflammatory potential, but the mechanisms of action need to be validated. Aims To investigate the anti-inflammatory effect of fruit ethanolic extract. Methods The extract, prepared via 95% ethanolic maceration, underwent HPLC analysis for quality control using L-asarinin as a standard. Its anti-inflammatory effects were evaluated using the cyclooxygenase inhibitor assay and RAW 264.7 macrophage cells through MTT cytotoxicity, COX inhibition, and RT-PCR assays, measuring inflammatory gene expression (COX-1, COX-2, IL-1β, IL-6, TNF-α). Statistical analysis (One-way ANOVA) assessed the significance of findings. Results ZL1 extract, obtained with a 14.32% yield and containing 0.040 % w/w L-asarinin, demonstrated an IC50 of 102.46 µg/mL on RAW 264.7 cells. Notably, ZL1 inhibited COX-2 activity in a dose-dependent manner, while showing no effect on COX-1. Gene expression analysis in LPS-inflamed RAW 264.7 cells further revealed that ZL1 down-regulated COX-2, IL-1β, IL-6, and TNF-α at concentrations as low as 12.5 µg/mL, indicating its selective anti-inflammatory potential. Conclusion Zanthoxylum myriacanthum ethanolic extract (ZL1) selectively inhibited COX-2. It significantly suppressed inflammatory genes (COX-2, IL-1β, IL-6, TNF-α) in LPS-induced RAW264.7 cells at 12.50, 25 and 50 µg/mL, demonstrating its potent anti-inflammatory effects.