Preventive effect of Teucrium polium on learning and memory deficits in diabetic rats.
BACKGROUND
Cognitive impairment occurs in diabetes mellitus. Teucrium polium L. (Lamiaceae) has been used in folk medicine to improve mental performance. Here we hypothesized that chronic treatment with an aqueous extract of Teucrium polium (100, 200 and 400 mg/kg, p.o.) would have an effect on passive avoidance learning (PAL) and memory in control and streptozocin-induced diabetic rats.


METHODS
Treatments were begun at the onset of hyperglycemia, and PAL was assessed 30 days later. A retention test was performed 24 h (hours) after training. After PAL and memory assessment, animals were weighed and blood samples were drawn for plasma glucose measurement.


RESULTS
Diabetes caused impairment in acquisition of PAL and retrieval of memory. Teucrium polium treatment (200 and 400 mg/kg) improved learning and memory in control rats and reversed learning and memory deficits in diabetic rats. The 100 mg/kg dose did not affect cognitive function. Teucrium polium treatment partially improved the reduced body weight and hyperglycemia of treated diabetic rats, although the differences were not significant compared to non-treated diabetic rats.


CONCLUSIONS
These results show that Teucrium polium prevented the deleterious effects of diabetes on PAL and memory. Antioxidant, anticholinesterase and hypoglycemic effects of Teucrium may be involved in the obtained effects. Therefore, Teucrium polium appears to be a promising candidate for memory improvement in diabetes, but this needs confirmation by future clinical studies.
Department of Biology, School of Basic Sciences, Bu-Ali Sina University, Hamedan, Iran. p.hasanein@basu.ac.ir
Parisa
P
Hasanein
Siamak
S
Shahidi
D000704:Analysis of Variance; D000818:Animals; D000975:Antioxidants / Q000494:pharmacology; D001362:Avoidance Learning / Q000187:drug effects*; D001786:Blood Glucose / Q000378:metabolism; D002800:Cholinesterase Inhibitors / Q000494:pharmacology; D003921:Diabetes Mellitus, Experimental / Q000150:complications*; D007004:Hypoglycemic Agents / Q000494:pharmacology; D007859:Learning Disabilities / Q000209:etiology / Q000517:prevention & control*; D008569:Memory Disorders / Q000209:etiology / Q000517:prevention & control*; D010936:Plant Extracts / Q000494:pharmacology* / Q000627:therapeutic use; D051381:Rats; D031367:Teucrium
D000975:Antioxidants; D001786:Blood Glucose; D002800:Cholinesterase Inhibitors; D007004:Hypoglycemic Agents; D010936:Plant Extracts; C040618:teucrium extract