Department of Pharmacology and Therapeutics, Faculty of Basic Medical Sciences, College of Health Sciences, Ladoke Akintola University of Technology Ogbomoso, Osogbo, Nigeria.
Department of Microbiology and Parasitology, Ladoke Akintola University of Technology Ogbomoso, Nigeria.
Cent Nerv Syst Agents Med Chem. 2020;20(3):194-205. doi: 10.2174/1871524920666200705221956.
The study was designed to investigate the anti-nociceptive activity of Euphorbia hirta leaf and its possible mechanism of action.
The extract of Euphorbia hirta obtained from the leaf was prepared as per standard procedures and evaluated at the three doses (300, 600, and 1200 mg/kg, i.p). The extract was screened for anti-nociceptive activity using heat-induced (tail-flick) and chemical-induced (acetic acid-induced writhing and formalin-induced paw lick) nociception models in mice. The possible mechanism of action of the extract was evaluated using antagonists of notable nociceptive pathways.
Intraperitoneal administration of Euphorbia hirta extract at the doses of 600 and 1200 mg/kg significantly (p<0.05) reduced the formalin-induced paw licking in both neurogenic and inflammatory phases of the test. While administration of the extract at the dose of 300 mg/kg significantly inhibited the pain due to formalin in the inflammatory phase but not in the neurogenic phase. The anti-nociceptive effect of Euphorbia hirta extract increased the reaction time to thermal stimulus, also inhibited the acetic acid-induced writhing dose-dependently. The antinociceptive effect exhibited by Euphorbia hirta extract in the formalin test was reversed by the administration of naloxone, theophylline, and atropine. Glibenclamide, nifedipine, and yohimbine, however, did not significantly block the anti-nociceptive effect of the extract. Meanwhile, methylene blue administration enhanced the anti-nociceptive effect of the extract.
The results indicated that Euphorbia hirta extract produces a dose-related antinociceptive effect in several models of chemical and thermal pain, through mechanisms that might involve interaction with adenosine, cholinergic, and opioid receptors.
本研究旨在探究大飞扬草叶的镇痛活性及其可能的作用机制。
按照标准程序制备大飞扬草叶提取物，并在三个剂量（300、600 和 1200 mg/kg，ip）下评估其镇痛活性。使用热诱导（尾巴摆动）和化学诱导（醋酸诱导扭体和福尔马林诱导舔足）疼痛模型筛选提取物的镇痛活性。使用显著疼痛途径的拮抗剂评估提取物的可能作用机制。
腹腔给予大飞扬草叶提取物 600 和 1200 mg/kg 剂量可显著（p<0.05）减少福尔马林诱导的舔足反应，包括神经源性和炎症相。而给予 300 mg/kg 剂量时，提取物仅在炎症相抑制了福尔马林引起的疼痛，而在神经源性相无作用。大飞扬草叶提取物的镇痛作用增加了对热刺激的反应时间，还剂量依赖性地抑制了醋酸诱导的扭体。福尔马林试验中，大飞扬草叶提取物的镇痛作用被纳洛酮、茶碱和阿托品逆转。然而，格列本脲、硝苯地平和育亨宾并没有显著阻断提取物的镇痛作用。同时，美蓝给药增强了提取物的镇痛作用。
结果表明，大飞扬草叶提取物在几种化学和热痛模型中产生了剂量相关的镇痛作用，其作用机制可能涉及与腺苷、胆碱能和阿片受体的相互作用。
