Protective Effects of Magnolia kobus DC. Extract on Inflammatory Response and Alveolar Bone Loss in Ligature-Induced Periodontitis Rats

Periodontitis is a chronic inflammatory condition characterized by dysregulated immune responses that promote alveolar bone destruction. Targeting inflammatory signaling pathways has therefore become an important area of investigation. This study investigated the anti-inflammatory and bone-protective effects of Magnolia kobus DC. extract (MKE) in a ligature-induced periodontitis rat model. Rats were assigned to five groups (n = 5 per group): non-ligature control, ligature control, doxycycline (20 mg/kg), MKE 100 mg/kg, and MKE 400 mg/kg, and treated orally for eight weeks. Periodontal damage and alveolar bone loss were assessed by micro-computed tomography (micro-CT), gingival index, and tooth mobility. Micro-CT analysis demonstrated a dose-dependent reduction in alveolar bone loss, as evidenced by a significant decrease in the cementoenamel junction–alveolar bone crest (CEJ–ABC) distance and reduced furcation involvement in MKE-treated groups compared with the ligature control group, while tooth mobility scores were significantly improved. Serum levels of receptor activator of nuclear factor kappa-B ligand, interleukin-1β, tumor necrosis factor-α, and cyclooxygenase-2 were significantly decreased, while nuclear factor kappa-B signaling was suppressed in gingival tissue. The extract also significantly reduced matrix metalloproteinases 3, 8, 9, and 13, and increased collagen type I and II expression. In summary, MKE exerted anti-inflammatory and bone-protective properties, effectively reducing alveolar bone loss and maintaining periodontal structure. These findings support MKE’s potential application as a natural anti-inflammatory and bone-protective agent and as a functional food ingredient for periodontitis prevention and treatment, meriting further clinical evaluation.