Hydroalcoholic extract of Melilotus officinalis alleviates neuropathic pain in a rat model

Background: Neuropathic pain (NP) is characterized by abnormal hypersensitivity and spontaneous pain, posing a significant clinical challenge due to its complex etiology and limited treatment options. Current therapies often yield inadequate relief and may lead to adverse effects. Emerging evidence indicates that oxidative stress and diminished serum antioxidant capacity play a role in the pathophysiology of NP. Melilotus officinalis, recognized for its antioxidant and anti-inflammatory properties, has shown potential as a therapeutic agent.Objectives: This study aimed to investigate the effects of Melilotus officinalis extract on NP induced by chronic constriction injury (CCI) of the sciatic nerve in rats.Methods: Male rats were randomly assigned to five groups: control, CCI, and three treatment groups receiving varying doses (250, 500, 1000 mg/kg) of Melilotus officinalis extract via gavage for 21 days. The CCI model was employed to induce NP. Behavioral assessments, including Thermal Hyperalgesia, Thermal Allodynia, and Mechanical Allodynia, were conducted alongside biochemical analyses to measure total antioxidant capacity (TAC), malondialdehyde (MDA), superoxide dismutase (SOD), and glutathione peroxidase (GPx).Results: Rats treated with Melilotus officinalis extract demonstrated a significant increase in pain threshold compared to both the control and CCI groups (p<0.05). A dose-dependent relationship was observed, with higher doses associating with enhanced pain relief (500 mg/kg: p=0.01; 1000 mg/kg: p<0.001). Biochemical analyses indicated that CCI reduced TAC, which was restored by the extract at doses of 500 mg/kg (p=0.03) and 1000 mg/kg (p<0.001). Additionally, MDA levels significantly decreased with the 1000 mg/kg dose of the extract (p<0.001). While the extract did not significantly affect SOD activity (p>0.05), it markedly increased GPx activity in treated rats (p<0.05).Conclusion: This study provides preclinical evidence supporting the potential efficacy of Melilotus officinalis extract in managing neuropathic pain. However, these findings are preliminary, necessitating further research, including rigorous clinical trials, to elucidate the mechanisms of action and evaluate the safety and effectiveness of Melilotus officinalis in human patients.