Medicinal Plants Research Center, Federal University of Piauí, Teresina, Brazil.
J Ethnopharmacol. 2010 May 27;129(2):227-31. doi: 10.1016/j.jep.2010.03.009. Epub 2010 Mar 19.
Zanthoxylum rhoifolium Lam. (Rutaceae) is locally known as "mamica de cadela", and its bark is popularly used for toothache and earache. The objective of this study was to investigate the antinociceptive effect of the ethanolic extract from this species' stem bark (EtOH), its fractions of partition (hexane-HEX, ethyl acetate-AcOEt, aqueous-AQ) and lupeol (a triterpene obtained from HEX) in models of acute pain.
Male and female Swiss mice (25-35 g, n=6-12 animals/group) were used to assess acute toxicity and nociception (Animal Ethics Committee/UFPI, No. 09/2008). Acute toxicity was studied up to 2 g/kg p.o. of EtOH. In the formalin test (2%, 20 microL/paw), the licking time of the stimulated paw was quantified during the first 5 min (first phase) and at 15-30 min (second phase), 1h after oral treatment with EtOH, HEX, AcOEt or saline, and 30 min after use of morphine-MOR (5 mg/kg i.p.). The same response evoked by capsaicin (2 microg/20 microL/paw) was quantified during 5 min, after administration of EtOH, HEX, AcOEt, AQ, saline and MOR. The licking time of the paw that was stimulated with glutamate (10 micromol/20 microL) was measured (15 min) after treatment with EtOH, HEX, AcOEt, AQ, lupeol, saline or MK801 (0.03 mg/kg, i.p.). Mice were submitted to the rota-rod task and open-field test in order to assess any non-specific muscle-relaxant or sedative effects of EtOH (250 mg/kg p.o.) and HEX (500 mg/kg p.o.).
The animals did not exhibit any acute toxicity to EtOH (up to 2 g/kg p.o.), so it was not possible to calculate the LD50. EtOH, HEX and AcOEt (62.5-250 mg/kg) produced a significant antinociceptive effect in the formalin and capsaicin tests. However, AQ was ineffective. EtOH, HEX, AcOEt and lupeol reduced the glutamate-evoked nociceptive response, but AQ had no effect. EtOH and HEX did not alter the locomotion of animals in the open-field or rota-rod tests, which suggest a lack of a central depressant effect.
The results confirm the popular use of Zanthoxylum rhoifolium as an analgesic, and contribute to the pharmacological knowledge of this species because it was shown that EtOH and its less polar partition fractions (HEX, AcOEt) have an antinociceptive effect in models of chemical nociception, and that lupeol appears to be one of the constituents responsible for this effect.
花椒（芸香科）在当地被称为“mamica de cadela”，其树皮被广泛用于治疗牙痛和耳痛。本研究的目的是研究该物种茎皮的乙醇提取物（EtOH）、其分配部分（正己烷-HEX、乙酸乙酯-AcOEt、水-AQ）和齐墩果酸（从 HEX 获得的三萜）在急性疼痛模型中的镇痛作用。
雄性和雌性瑞士小鼠（25-35g，n=6-12 只/组）用于评估急性毒性和痛觉（UFPI 动物伦理委员会，No.09/2008）。急性毒性研究最高剂量为 2g/kg p.o.的 EtOH。在福尔马林试验（2%，20μL/爪）中，在口服 EtOH、HEX、AcOEt 或生理盐水后 1h，以及使用吗啡-MOR（5mg/kg i.p.）后 30min，量化刺激爪的舔舐时间。在给药 EtOH、HEX、AcOEt、AQ、生理盐水和 MOR 后 5min 量化辣椒素（2μg/20μL/爪）引起的相同反应。在给予 EtOH、HEX、AcOEt、AQ、齐墩果酸、生理盐水或 MK801（0.03mg/kg，i.p.）后 15min 测量谷氨酸（10μmol/20μL）刺激爪的舔舐时间。小鼠进行旋转棒任务和旷场试验，以评估 EtOH（250mg/kg p.o.）和 HEX（500mg/kg p.o.）的任何非特异性肌肉松弛或镇静作用。
动物对 EtOH（高达 2g/kg p.o.）没有表现出任何急性毒性，因此无法计算 LD50。EtOH、HEX 和 AcOEt（62.5-250mg/kg）在福尔马林和辣椒素试验中产生了显著的镇痛作用。然而，AQ 无效。EtOH、HEX、AcOEt 和齐墩果酸减少了谷氨酸引起的疼痛反应，但 AQ 没有作用。EtOH 和 HEX 没有改变动物在旷场或旋转棒试验中的运动，这表明它们没有中枢抑制作用。
结果证实了花椒作为镇痛药的民间用途，并为该物种的药理学知识做出了贡献，因为已经表明 EtOH 及其非极性分配部分（HEX、AcOEt）在化学痛觉模型中具有镇痛作用，而齐墩果酸似乎是具有这种作用的成分之一。
