Effects of Zanthoxyli Pericarpium Extracts on Ligature-Induced Periodontitis and Alveolar Bone Loss in Rats

Zanthoxyli Pericarpium (ZP), the dried pericarp of mature fruits of Zanthoxylum schinifolium Siebold and Zucc., has traditionally been used in East Asian medicine for its medicinal properties, but its therapeutic potential in periodontitis has not been elucidated. In the present study, we investigated the effects of ZP on ligature-induced experimental periodontitis (EPD) in male Sprague Dawley rats. Animals were assigned to vehicle control, ligature control, ZP-treated (25, 50, and 100 mg/kg), or indomethacin-treated (5 mg/kg) groups (n = 10 per group) and orally administered the respective treatments daily for 10 days after ligature placement. ZP significantly reduced anaerobic bacterial proliferation and inflammatory cell infiltration in gingival tissue. ZP suppressed the production of inflammatory mediators, such as tumor necrosis factor-α and interleukin-1β, in both gingival tissues and lipopolysaccharide-stimulated RAW 264.7 macrophages, through inhibition of the mitogen-activated protein kinase (MAPK) and nuclear factor-κB (NF-κB) signaling pathways. In addition, ZP decreased myeloperoxidase activity and reduced matrix metalloproteinase-8 expression, thereby preserving collagen areas. ZP also restored the receptor activator of NF-κB ligand/osteoprotegerin (RANKL/OPG) balance, leading to a reduction in osteoclast numbers and their occupancy on the alveolar surface, and it effectively ameliorated horizontal alveolar bone loss. Furthermore, ZP exhibited antioxidant effects by lowering malondialdehyde levels and inducible nitric oxide synthase activity in gingival tissues. Statistical analysis was performed using ANOVA followed by a post hoc test, with significance set at p < 0.05. These findings indicate that ZP mitigates periodontitis through combined antimicrobial, anti-inflammatory, antioxidant, and anti-resorptive actions, supporting its potential as a therapeutic candidate for periodontitis.