Appraisal of scopolamine-induced antiamnesic effect in mice and in vitro antiacetylcholinesterase and antioxidant activities of some traditionally used Lamiaceae plants

Ethnopharmacological relevance

Salvia species and Melissa officinalis are used for their memory-enhancing effects in European folk medicine. Teucrium polium was reported to be used in Anatolia for memory-enhancement in a very old book written by an Ottoman herbalist–physician.

Aim of the study

Alzheimer's disease (AD) is a progressive neurological disorder mostly affecting the elder population. Currently, there is no cure for the treatment of severe type of AD. Therefore, in this study, the hydroalcoholic extracts of three traditionally used Lamiaceae species for memory-enhancement; Salvia triloba L., Melissa officinalis L., and Teucrium polium L., were assessed for their in vivo antiamnesic activity along with in vitro anticholinesterase and antioxidant activities.

Materials and methods

Scopolamine-induced antiamnesic activity was determined in mice by passive avoidance test, while anticholinesterase effect was measured by spectrophotometric Ellman method at 0.25, 0.50, 1.0, and 2.0 mg ml⁻¹ and antioxidant activity was assessed by scavenging effect against 2,2-diphenylpicrylhydrazyl (DPPH). Total phenol contents of the extracts were determined by Folin-Ciocalteau method.

Results

Salvia triloba was the most effective in antiamnesic experiment at 100, 200, and 400 mg kg⁻¹ doses having 22.7, 57.1, and 71.4% of relative effects, respectively. Teucrium polium was also active dose-dependently, whereas Melissa officinalis was completely inactive. In the anticholinesterase assay, the extracts showed similar inhibitions against acetylcholinesterase and Teucrium polium had the highest inhibition (65.8% at 1.0 mg ml⁻¹). Concerning the antioxidant effect, all the extracts exerted the highest activity among all having IC₅₀ values between 0.227 and 0.428 mg/ml.

Conclusion

Our data suggest that Teucrium polium among the screened plants deserves to be examined further as a herbal alternative for AD treatment.