Background & objectives: Salvia officinalis is one of the memory-enhancing herbs that were used in the past. On the other hand, iron oxide nanoparticles which are widely used in medicine and industry may impair the brain process related to memory. In this investigation, the effect of hydro-alcoholic extract of Salvia officinalis on iron oxide nanoparticle induced memory impairment and the role of beta-adrenergic receptors in this effect were studied.

Methods: To assess the inhibitory avoidance memory, animals were trained in the step-down task and drugs (saline, hydro-alcoholic extract of sage leaves, nanoparticles of iron oxide and propranolol) were injected immediately after training by intraperitoneal (ip) injections. Long-term memory was tested 24 hours later and step-down latencies were recorded.

Results: Administration of iron oxide nanoparticles (5 mg/kg, ip) impaired memory retrieval. Salvia officinalis extract (40 mg/kg, ip) also prevented iron oxide nanoparticle induced long-term memory impairment. On the other hand, administration of propranolol (5, 10 mg/kg, ip) before Salvia officinalis extract (40 mg/kg, ip) and iron oxide nanoparticles (5 mg/kg, ip) attenuated the effect of Salvia officinalis extract.

Conclusion: It seems that extract of Salvia officinalis leaves decreases iron oxide nanoparticle induced memory impairment. Beta-adrenergic mechanisms are possibly involved in these effects of Salvia officinalis extract.

Background & objectives: Zinc as one of the most important trace elements is needed for proper functioning of the nervous system and homeostasis. Many studies show that stress causes memory impairment through various mechanisms, including oxidative stress induction and some mechanisms which are directly effecting brain function. So, in this work we assessed the effect of zinc chloride on passive avoidance memory and oxidative stress following acute stress in male rats.

Methods: In this study, 50 male Wistar rats were used in five groups: control, sham, stress, zinc chloride treatment and zinc chloride treatment before stress induction. For stress induction, rats were restrained (not immobilized) for 6 h/day, 7 days in a Plexiglas restrainer, and treated rats received an oral dose of zinc chloride 32 mg/kg/day by gavage for 6 days. At the end of the experiment, passive avoidance memory was avaluated by shuttle box and some oxidative damage markers were determined in all groups.

Results: Results of this study showed that animals which were exposed to stress showed a significant decrease in passive avoidance memory compared to control group (p<0.01) and the oxidative stress parameters in this group showed significant changes compared to the control group (p<0.05). While passive avoidance memory and oxidative stress parameters in group treated with zinc chloride were nearly closed to control group.

Conclusion: According to our results, zinc chloride with antioxidant properties can have a protective effect on memory impairment and oxidative stress induced by stress.

Background & objectives: Propolis is a natural product with powerful antioxidant and therapeutic effects. The aim of this study was to investigate the effect of propolis on passive avoidance memory in adult male mice.

Methods: In this study, 40 adult male mice were divided into 8 groups, including control, sham (solvent) and 3 treatment groups orally treated with 50, 100 and 200 mg/kg of propolis, respectively for two weeks before and one week after treatment. Then, passive avoidance learning and memory were recorded in timescales of 24 and 48 hours, 4 days and a week after shock by the shuttle box. Data were analyzed by ANOVA and Dunnett’s post hoc tests, and p<0.05 was considered significant.

Results: Administration of propolis (50 mg/kg) significantly increased the dark chamber entering time at intervals of 24 and 48 hours (p<0.001) and at concentrations of 100 and 200 mg/kg in all time periods after the shock (p<0.001).

Conclusion: Oral administrations of propolis can improve learning and memory dose-dependently in adult male mice.