Sharifzadeh Mohammad, Shamsa Fazel, Shiran Somayeh, Karimfar Mohammad H, Miri Abdol H, Jalalizadeh Hassan, Gholizadeh Shervin, Salar Fatemeh, Tabrizian Kaveh
Department of Toxicology-Pharmacology and Center of Excellence of Toxicology, Pharmaceutical Sciences and Medicinal Plants Research Centers, Faculty of Pharmacy, Tehran University of Medicinal Sciences, Tehran, Iran.
Planta Med. 2008 Apr;74(5):485-90. doi: 10.1055/s-2008-1074494. Epub 2008 Apr 10.
In the present study, the time course of the effects of Glycyrrhiza glabra L. (Leguminosae) aqueous extract (GE), administered systemically to rats, on the spatial memory retention in the Morris water maze was investigated. The dose of glycyrrhizin (GL), i. e., 0.5, 2.5 and 5 mg/mL in daily water intake of GE was administered to three groups of rats. The first, second and third groups received GE for 1, 2 and 4 weeks, respectively (each group included 3 subgroups). Three additional control groups of animals received only tap water during the same periods of time. After terminating the treatments, all animals were trained for four days; each day included one block and each block contained four trials. Test trials were conducted 48 h after the completion of the training period. Nicotine (1 microg/side) was infused into the CA1 region of the hippocampus as a positive drug control. GE treatment decreased both escape latency and traveled distance, but not swimming speed, compared with control, suggesting significant spatial memory retention enhancement by GE. Statistical analysis did not show any significant difference between GE-treated animals and the nicotine group in escape latency and traveled distance. At the end of the testing trials plasma samples were collected and the concentrations of glycyrrhetinic acid (GA) as a major metabolite of GL were measured in the different groups of treated rats. The maximum concentration was observed after four weeks of GE administration at 5 mg/mL of GL. These results showed that the enhancement effect of GE on spatial memory retention does not correlate with GA blood levels.
在本研究中，研究了将甘草（豆科）水提取物（GE）全身给予大鼠后，其对Morris水迷宫中空间记忆保持的影响的时间进程。将甘草酸（GL）的剂量，即分别以0.5、2.5和5 mg/mL的浓度添加到GE的每日饮水中，给予三组大鼠。第一组、第二组和第三组大鼠分别接受GE处理1周、2周和4周（每组包括3个亚组）。另外三个对照组动物在相同时间段内仅饮用自来水。处理结束后，所有动物均接受为期四天的训练；每天包括一个训练单元，每个训练单元包含四次试验。在训练期结束后48小时进行测试试验。将尼古丁（1微克/侧）注入海马体CA1区作为阳性药物对照。与对照组相比，GE处理降低了逃避潜伏期和游动距离，但未降低游泳速度，表明GE显著增强了空间记忆保持能力。统计分析显示，GE处理组动物与尼古丁组在逃避潜伏期和游动距离方面没有显著差异。在测试试验结束时，采集血浆样本，并测量不同处理组大鼠中作为GL主要代谢产物的甘草次酸（GA）的浓度。在给予5 mg/mL GL的GE四周后观察到最大浓度。这些结果表明，GE对空间记忆保持的增强作用与GA的血药浓度无关。
