The aim of the present study was to investigate the antihyperglycemic and protective potential of crocin, a pharmacologically active constituent of Crocus sativus L., in streptozotocin-induced diabetic rats. Rats were administered crocin intraperitoneally at doses of 15, 30, and 60 mg/kg of body weight for 6 weeks. The levels of thiobarbituric acid reactive substance (TBARS) and total thiol (SH) groups were measured in the liver and kidney at the end of 6 weeks. Under our experimental conditions, crocin at a dose of 60 mg/kg was found to significantly reduce the blood glucose level in diabetic animals. In addition, there was a significant increase in TBARS levels and decreased total thiol concentrations in the liver and kidney of diabetic animals. Crocin, at doses of 30 and 60 mg/kg, appears to exert an antioxidative activity demonstrated by a lowering of lipid peroxidation levels in these organs. In conclusion, our findings suggest that crocin has the hypoglycemic and antioxidative properties in streptozotocin-induced diabetes and it may be useful in the management of diabetic patients.

Ischemia-reperfusion injury (I/R injury) is a common feature of ischemic stroke which occurs when blood supply is restored after a period of ischemia. Although stroke is an important cause of death in the world, effective therapeutic strategies aiming at improving neurological outcomes in this disease are lacking. Various studies have suggested the involvement of different mechanisms in the pathogenesis of I/R injury in the nervous system. These mechanisms include oxidative stress, platelet adhesion and aggregation, leukocyte infiltration, complement activation, blood-brain barrier (BBB) disruption, and mitochondria-mediated mechanisms. Curcumin, an active ingredient of turmeric, can affect all these pathways and exert neuroprotective activity culminating in the amelioration of I/R injury in the nervous system. In this review, we discuss the protective effects of curcumin against I/R injury in the nervous system and highlight the studies that have linked biological functions of curcumin and I/R injury improvement.

Development and design of agents derived from natural sources with neuroprotective properties have received considerable attention. In the literature, it has been stated that these polyphenolic molecules have low adverse impacts and high efficacy when used in pathological conditions. Dietary flavonoids as a subgroup of polyphenols are bioactive products, extracted from several types of vegetables and fruits. Luteolin (3',4',5,7-tetrahydroxyflavone, LUT) is a widespread flavone known to have antioxidant and cytoprotective properties related to nuclear factor erythroid 2-related factor 2-(Nrf2) pathway. Extensive in vitro and in vivo investigations have indicated that LUT exhibits beneficial neuroprotective properties via different mechanisms. However, its psychopharmacological mechanisms are presently investigated in fewer studies. Therefore, we aimed to evaluate the neuroprotective impacts of LUT against central nervous system (CNS) disorders by reviewing available literature. Herein, we also reviewed the studies to understand the underlying mechanisms of LUT for curing CNS disorders.

Functional consequences of hypothyroidism include impaired learning and memory and inability to produce long-term potentiation (LTP) in hippocampus. Olibanum has been used for variety of therapeutic purposes. In traditional medicine, oilbanum is used to enhance learning and memory. In the present study the effect of olibanum on memory deficit in hypothyroid rats was investigated. Male wistar rats were divided into four groups and treated for 180 days. Group 1 received tap drinking water while in group 2, 0.03% methimazol was added to drinking water. Group 3 and 4 were treated with 0.03% methimazole as well as 100 and 500 mg/kg olibanum respectively. The animals were tested in Morris water maze. The swimming speed was significantly lower and the distance and time latency were higher in group 2 compared with group 1. In groups 3 and 4 the swimming speed was significantly higher while, the length of the swim path and time latency were significantly lower in comparison with group 2. It is concluded that methimazole-induced hypothyroidism impairs learning and memory in adult rats which could be prevented by using olibanum.

INTRODUCTION:Severe cognitive impairment follows thyroid hormone deficiency during the neonatal period. The role of nitric oxide (NO) in learning and memory has been widely investigated.METHODS:This study aimed to investigate the effect of hypothyroidism during neonatal and juvenile periods on NO metabolites in the hippocampi of rats and on learning and memory. Animals were divided into two groups and treated for 60 days from the first day of lactation. The control group received regular water, whereas animals in a separate group were given water supplemented with 0.03% methimazole to induce hypothyroidism. Male offspring were selected and tested in the Morris water maze. Samples of blood were collected to measure the metabolites of NO, NO2, NO3 and thyroxine. The animals were then sacrificed, and their hippocampi were removed to measure the tissue concentrations of NO2 and NO3.DISCUSSION:Compared to the control group's offspring, serum thyroxine levels in the methimazole group's offspring were significantly lower (P<0.01). In addition, the swim distance and time latency were significantly higher in the methimazole group (P<0.001), and the time spent by this group in the target quadrant (Q1) during the probe trial was significantly lower (P<0.001). There was no significant difference in the plasma levels of NO metabolites between the two groups; however, significantly higher NO metabolite levels in the hippocampi of the methimazole group were observed compared to controls (P<0.05).CONCLUSION:These results suggest that the increased NO level in the hippocampus may play a role in the learning and memory deficits observed in childhood hypothyroidism; however, the precise underlying mechanism(s) remains to be elucidated.

Thyroid hormones (THs) have a wide and important range of effects within the central nervous system beginning from fetal life and continuing throughout the adult life. Thyroid disorders are one of the major causes of cognitive impairment including Alzheimer's disease (AD). Several studies in recent years have indicated an association between hypothyroidism or hyperthyroidism and AD. Despite available evidence for this association, it remains unclear whether thyroid dysfunction results from or contributes to the progression of AD. This review discusses the role of THs in learning and memory and summarizes the studies that have linked thyroid function and AD. Eventually, we elaborate how THs may be effective in treating AD by putting forward potential mechanisms.

The role of ovarian hormones, nitric oxide, and their interaction on learning and memory has been widely investigated. The present study was carried out to evaluate the effect of acute (A) and chronic (C) L-arginine (L-Arg) administration on learning and memory in ovariectomized (OVx) rats. Forty-five rats were divided into six groups: 1) sham, 2) OVx, 3) sham-L-Arg-A, 4) OVx-L-Arg-A, 5) sham-L-Arg-C, 6) OVx-L-Arg-C. The animals of sham-L-Arg-A and OVx-L-Arg-A were acutely treated with 500 mg/kg of L-Arg during 5 test days. Sham-L-Arg-C and OVx-L-Arg-C chronically received 500 mg/kg/day of L-Arg during 8 weeks before 5 test days. The animals in sham and OVx groups received 1 ml/kg saline instead of L-Arg. At the end of the experiment, the animals were tested in Morris water maze and the escape latency and traveled path to reach the platform were compared between groups. Results showed that the escape latency and traveled path in OVx group were significantly higher than in sham group ( p <0.05). The animals in OVx-L-Arg-A group had significantly lower traveled path length and escape latency compared to OVx group ( p <0.001). Chronic treatment by L-Arg had no significant effect on learning and memory in OVx and sham-operated animals. It seems that L-Arg has a role in Morris water maze tasks disturbances in OVx rats but it needs to be further investigated.

BackgroundWe investigated the potential of galangal rhizomes to induce cytotoxic and apoptotic effects in the cultured human breast carcinoma cell line, (MCF-7) in compare with the non-malignant (MRC-5) cells.MethodsBoth cells were cultured in DMEM medium and treated with galangal rhizomes for three consecutive days. The percentage of apoptotic cells was determined by flow cytometry using Annexin-V fluorescein isothiocyanate.ResultsThe results showed that the ethanolic extract of galangal rhizomes decreased cell viability in the malignant cells as a concentration- and time- dependent manner. The IC50 values against MCF-7 were determined at 400.0 ± 11.7 and 170.0 ± 5.9 μg/ml after 48 and 72 h respectively. The morphology of MCF-7 cells treated with the ethanolic extract confirmed the cell proliferation assay results. Alpinia galanga induced apoptosis in MCF-7 cells, as determined by flow cytometry.ConclusionsWe concluded that the extract of Alpinia galanga exerts pro-apoptotic effects in a breast cancer-derived cell line and could be considered as a potential chemotherapeutic agent in breast cancer.