Cholinesterase Inhibitory, Anti-oxidant and Anti-tyrosinase Activities of Three Iranian Species of Dracocephalum

Background and objectives: Dracocephalum species are mentioned in Iranian traditional medicine for enhancement of cognitive performance. In the present study, the acetyl cholinesterase inhibitory and butyryl cholinesterase inhibitory activities as well as the anti-oxidant and anti-tyrosinase effects of three Iranian Dracocephalum species (D. kotschyi, D. multicaule, D. polychaetum was analyzed). Methods: The extractions were performed stepwise with hexane, chloroform, ethyl acetate (EtOAC), methanol (MeOH) and water. AChE and BChE inhibitory properties were measured by a microplate assay. Total phenolic content of all extracts were also evaluated and anti-oxidant activities of the extracts were assessed using DPPH, FRAP assays. Tyrosinase inhibitory activity was measured using the modified dopachrome method with L-DOPA as the substrate. Results: The results showed that the EtOAc extract of D. multicaule and MeOH extract of D. kotschyi were the most active anti-oxidant and anti-tyrosinase extracts which showed the highest amounts of phenolic compounds. Dracocephalum multicaule demonstrated the most considerable activity in AChE inhibition and D. polychaetum the highest activity in BChE inhibition. The aqueous extract of D. multicaule inhibited both AChE and BChE. Conclusion: Dracocephalum multicaule can be suggested as a proper natural candidate for improvement of cognitive disorders.