Quantification of the analgesic effect of Ximenia americana bark extracts and involvement of opioid receptors

• Author Details:   
• Yacouba Adebo Adehouni ^*
• Amara Kamagate
• Paul Maomy
• Sylvain Landry Kouakou
• Généviève Irie-N’guessan
• N'doua Gisele Kouakou-Siransy

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Background: Pain is a common symptom requiring timely treatment. This study aimed to quantify the analgesic potential of a decoctate (DXA) and a hydroethanol extract (EHEXA) of Ximenia americana, and also to assess the role of opioid receptors.

Materials and Methods: Analgesic effects were measured using Writhing and formaldehyde tests, and the mechanism was investigated by blocking opioid receptors. Efficacy (Emax) and potency (ED??) were the main evaluted pharmacodynamic parameters.

Results: In writhing test, both extracts reduced dose-dependently abdominal contortions for up to 90 minutes, with Emax values of 100%. ED?? ranged from 2.84 -1.60 mg/kg (DXA), 7.94 - 0.6 mg/kg (EHEXA), 19.05 - 16.50 mg/kg (paracetamol), and 2.81-3.16 mg/kg (tramadol).

In formaldehyde test, both extracts reduced again dose-dependently neurogenic and inflammatory pain. E_max values were 42% and 55% for neurogenic pain, and 65% and 82% for inflammatory pain (DXA and EHEXA, respectively). Potency (ED??) values were around 6 - 7.5 mg/kg of Ximenia americana.

Administration of naloxone (Opioid receptor antagonist) inhibited the analgesic effect of the extracts, with a reduction of 23 to 74% for DXA and 42 to 84% for EHEXA from 30 minutes to 90 minutes after, indicating opioid receptor involvement.

Conclusion: Ximenia americana extracts showed analgesic effects comparable to reference drugs (paracetamol, tramadol, ketoprofen) and may act as partial opioid receptor agonists at doses ?10 mg/kg, supporting their potential use in managing mild to moderate pain.

Keywords: Analgesics, Pharmacodynamic parameters, Mechanisms of action, Ximenia americana