No abstract

Cognitive decline induced by oxidative brain damage is the critical pathological hallmark of Alzheimer's disease. Studies have shown that individual administration of Boswellia serrata Roxb (BS), Zingiber officinale Roscoe (ZO) and Ginkgo biloba L. (GB) extracts improved memory and learning through a different mechanism of actions. This study aims to compare the individual effects of each extract with their co-administration on memory impairment induced by scopolamine in mice. Memory dysfunction was induced by a single dose of scopolamine (1 mg/kg, i.p) and extracts were administered intraperitoneally in different doses for one week. Memory performance of the mice was evaluated using the object recognition task (ORT) and passive avoidance test (PAT). The outcomes from ORT demonstrated that, ZO and GB extracts at 200 mg/kg and BS extract just in combination group significantly enhanced (by 95%) the memory loss induced by scopolamine (P < 0.05). On the other hand, PAT results revealed that BS extract at 60 and 90 mg/kg, ZO and GB extracts at 200 mg/kg and their combinations noticeably improved the latency time (by 80%). Although in PAT, co-administration of extracts was more effective than either alone doses in augmenting of the memory function, ORT results showed no considerable differences.

Background and purpose: Pregnant women experience different type of stresses which affect the fetus brain physiological processes like memory. Therefore, it is attractive to find the protective agents that are safe in the pregnancy and neutralize the stress induced manifestations. The aim of current study was to investigate the protective effects of melatonin on memory impairment induced by prenatal restraint stress in offspring rats. Materials and methods:In this experimental study, pregnant rats were randomly assigned to control, restraint stress group and four melatonin treated groups that received 3, 5, 10, and 50 mg/kg of melatonin concomitant with restraint stress. Restraint stress daily induced from 10 th to 21 st day of pregnancy. Melatonin was daily injected intraperitoneally before the restraint stress. One month after the birth, the memory of offspring was evaluated by measurement of "Discrimination" and "Recognition" indices using Object Recognition Task. Results: From the data, administration of 3 or 5 mg/kg melatonin did not show significant differences in Discrimination and Recognition indices compared to restraint stress group while injection of 10 or 50 mg/kg of melatonin significantly increased the above indices (P <0.001). There is no significant difference in indices values for 10 or 50 mg/kg of melatonin. Conclusion:The findings showed that prenatal restraint stress induced memory impairment in one month offspring rats. Administration of melatonin in high doses actively prevent restraint stress induced memory impairment.