Abstract
Papaver libanoticum is an endemic plant to Lebanese region (family Papaveraceae) that has not been investigated before. The present study aimed to explore the analgesic activity of dried ethanolic extract of Papaver libanoticum (PLE) using tail flick, hot plate, and acetic acid induced writhing models in mice. The involvement of opioid receptors in the analgesic mechanism was investigated using naloxone antagonism. Results demonstrated that PLE exhibited a potent dose dependent analgesic activity in all tested models for analgesia. The analgesic effect involved activation of opioid receptors in the central nervous system, where both spinal and supraspinal components might be involved. The time course for analgesia revealed maximum activity after three hours in both tail flick and hot plate methods, which was prolonged to 24 hours. Metabolites of PLE could be responsible for activation of opioid receptors. The EC50 of PLE was 79 and 50 mg/kg in tail flick and hot plate tests, respectively. The total coverage of analgesia by PLE was double that of morphine in both tests. In conclusion, PLE proved to have opioid agonistic activity with a novel feature of slow and prolonged effect. The present study could add a potential tool in the armaments of opioid drugs as a natural potent analgesic and for treatment of opioid withdrawal syndrome.
Highlights
Despite recent developments in pain therapies, the medical community still needs safe, effective, and potent analgesic drugs for the treatment of different painful conditions especially the chronic pain [1]
The analgesic activity of PLE was studied by the tail flick, hot plate, and acetic acid induced writhing tests, which are standard pharmacological models for the assessment of analgesia by natural products [28]
The present study demonstrates that Papaver libanoticum extract acts as a potent analgesic agent
Summary
Despite recent developments in pain therapies, the medical community still needs safe, effective, and potent analgesic drugs for the treatment of different painful conditions especially the chronic pain [1]. Thousands of patients with intense pain, such as that resulting from cancer or severe injury, must depend on current regimes (peripheral or centrally acting) like morphine, aspirin, and nonsteroidal anti-inflammatory drugs [2, 3]. Herbal therapy could be an interesting option for the treatment of opioid dependence and withdrawal [7]. Papaver libanoticum is a member of genus Papaver, endemic to Lebanese region, family Papaveraceae [8] It is a small herb with 5–30 cm stem, yellow-orange latex, and oblong leaves, covered with white silky hairs. Papaver species are very important medicinally as they are source for many pharmacologically active alkaloids [9]
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