effect of chronic administration of Aegle marmelos seed extract on learning and memory in diabetic rats

Diabetes mellitus is associated with disturbances of learning and memory and cognitive functioning. Aegle marmelos Corr. from Rutaceae family is widely used in Iranian folk medicine for the treatment of diabetes mellitus. Considering the beneficial antidiabetic and antioxidant potential of A. marmelos, this study was conducted to evaluate the effect of oral administration of A. marmelos on learning and spatial memory in diabetic rats using Morris water maze test. Considering the beneficial antidiabetic potential of A. marmelos, this study was conducted to evaluate the effect of chronic oral administration of A. marmelos as cognitive enhancer, on learning and spatial memory in diabetic rats using Morris water maze test. Male Wistar rats were randomly divided into normal-control, diabetic-control, and A. marmelos-treated diabetic groups [100, 250 and 500 mg/kg, p.o.]. Animals were treated for 4 weeks by A. marmelos or normal saline. Diabetes was induced by a single dose i.p. injection of streptozotocin [45 mg/kg]. In each group of animals, spatial learning and memory parameters were analyzed. Clear impairment of spatial learning and memory was observed in diabetic group versus normal-control group. A. marmelos showed dose dependent improvement in spatial learning and memory parameters that swimming time [Escape Latency] in normal-control and A. marmelos-treated diabetic animals rats was significantly [P< 0.01] lower than diabetic-control, while swimming speed was significantly [P< 0.05] higher. The study demonstrated that A. marmelos has significant protective affect against diabetes-induced spatial learning and memory deficits. This effect could be attributed to hypoglycemic, hypolipidemic and antioxidant activity of A. marmelos

[Effects of pioglitazone injection into hippocampal CA1 area on spatial learning and memory deficits in rats]

Pioglitazone from thiazolidinediones generation, represent a new antidiabetic drugs that have been introduced in the world recently. Thiazolidinediones can improve insulin resistance by activating the nuclear peroxoxisome proliferator activated receptor-gamma [PPAR-gamma] and increasing insulin sensitivity in their receptors. Insulin and its receptors are found in specific areas of CNS with a variety of region-specific functions. The effects of insulin in CNS are different from its direct glucose regulation in the periphery. Hippocampus and cerebral cortex distributed insulin/insulin receptor have been shown to be involved in brain cognitive functions. In the present study, the effect of pioglitazone microinjection into CA1 region of rat hippocampus using Morris water maze performance has been investigated. In this experimental study, male N-MRI rats were randomly divided into control, DMF [dimethyl formamide] and pioglitazone groups [0.001, 0.01, 0.1, 1, 10 microg/rat]. Drugs were injected [1 microl/rat] into CA1 region bilaterly during 1 min. Thirty minutes after the intrahippocampal injection of drugs, water maze training was started. Pioglitazone had a dose dependent effect. The spatial learning and memory didn't change with lower dose of pioglitazone, but improved with intermediate doses, while they impaired with higher dose. These results suggest that intrahippocampal injection of pioglitazone may have a dose-dependent effect on spatial learning and memory in rats in range of 0.001 to 1 microg/rat

Effects of boswellia papyrifera Gum extract on learning and memory in mice and rats

Learning is defined as the acquisition of information and skills, while subsequent retention of that information is called memory. The objective of the present study was to investigate the effect of aqueous extract of Boswellia papyrifera on learning and memory paradigms in mice and rats. This study was held at the Department of Pharmacology, Faculty of Pharmacy, Kermanshah University of Medical Science, Kermanshah, Iran from September 2006 to March 2008. Male Wistar rats and male NMR1 mice were randomly divided into control, B. papyrifera treated [50, 100, 150 mg/kg, p.o.], and piracetam [150 mg/kg] groups. Radial arm maze [RAM] and Morris water maze [MWM] were the screening tests used to assess the activity of B. papyrifera extract. The mice treated with B, papyrifera [50, 100 and 150 mg/kg] or piracetam [150 mg/kg] showed a decrease in number of days required to learned [P< 0.05] and time taken to find food by the learned mice in radial arm maze [P< 0.01]. In Morris water maze, rats treated with the above mentioned doses showed dose dependent improvement in spatial learning. Escape latency during swimming in water maze in piracetam and B. papyrifera treated animals was significantly lower [P< 0.01] than control. Swimming distance was also significantly lower [P< 0.05] in the treated groups. The results show facilitation of spatial learning and memory processes and thereby validate B. papyrifera traditional use of intelligence improving. The presence of alkaloids, flavonoids and saponins might be responsible for this activity of B. papyrifera

Analgesic and anti-inflammatory activity of teucrium chamaedrys leaves aqueous extract in male rats

Current study was undertaken to investigate the analgesic and anti-inflammatory effects of the aqueous extract of Teucrium chamaedrys in mice and rats. For evaluating of analgesic and anti-inflammatory activity, we used the carrageenan-and dextran-induced paw oedema, acetic acid-induced writhing, tail flick and formalin pain tests. The extract of T. chamaedrys [50-200 mg/kg] and acetylsalicylic acid [100 mg/kg] produced a significant [P< 0.01] inhibition of the second phase response in the formalin pain model, while only the high dose [200 mg/kg] of the extract showed an analgesic effect in the first phase. The extract also inhibited acetic acid-induced abdominal writhes in a dose-dependent manner. The tail flick latency was dose dependently enhanced by the extract but this was significantly [P< 0.05] lower than that produced by morphine [10 mg/kg]. The extract [25-250 mg/kg] administered 1 hr before carrageenan-induced paw swelling produced a dose dependent inhibition of the oedema. No effect was observed with the dextran-induced oedema model. Results of the phytochemical screening show the presence of alkaloids, flavonoids and triterpenoids in the extract. The data obtained also suggest that the anti-inflammatory and analgesic effects of the extract may be mediated via both peripheral and central mechanisms. The role of alkaloids, flavonoids and triterpenoids will evaluate in future studies

Antinociceptive effect of promethazine in mice

The present study was undertaken to investigate the nociception activity of promethazine, a tranquillizer devoid of hypnotic activity in mice. Antinociception was evaluated, using the acetic acid-induced writhing, tail flick, hot plate and formalin pain tests. Promethazine [4 and 6 mg/kg] and acetylsalicylic acid [100 mg/kg] produced a significant inhibition of the second phase response in the formalin pain model [P<0.05] and the drug couldn't show an antinociceptive effect in the first phase. Morphine [10 mg/kg] inhibited both first and second phase response [P<0.01]. Drug also showed a dose-dependent inhibition of acetic acid-induced abdominal writhes. The tail flick and hot plate latency weren't different from control [P>0.05] and administration of naloxone [0.1 mg/kg] couldn't block the antinociceptive effect of promethazine. The data obtained suggest that antinociceptive effects of the promethazine may be mediated via peripheral and not central mechanisms

sensitive liquid chromatographic method for the analysis of clarithromycin with pre-column derivatization: application to a bioequivalence study

A sensitive liquid chromatographic method for the analysis of clarithromycin- a macrolide antibiotic- in human serum, using pre-column derivatization with 9-fluorenylmethyl chloroformate [FMOC-Cl] is described. The method involved liquid - liquid extraction of the drug and an internal standard [amantadine] followed by pre-column derivatization of the analytes with FMOC-Cl. A mixture of 0.05 M phosphate buffer containing triethylamine [2 ml/l; pH 3.8] and methanol [17:83, v/v] was used as mobile phase and chromatographic separation was achieved on a Shimpack CLC-ODS column. The eluate was monitored by a fluorescence detector with respective excitation and emission wavelengths of 265 and 315 nm. The analytical method was linear over the concentration range of 0.025-10 mg/ml of clarithromycin in human serum with a limit of quantification of 0.025 mg/ml. The assay is sensitive enough to measure drug levels obtained in human single dose studies. In the present method, sensitivity and the running time of analysis have been improved and successfully applied in a bioequivalence study of three different clarithromycin preparations in 12 healthy volunteers