Screening of Medicinal Plants from Iranian Traditional Medicine for Acetylcholinesterase Inhibition

Abstract

To find new herbal compounds with an acetylcholinesterase (AChE) inhibitory effect, this study focused on herbal drugs and resins which have been used in Iranian traditional medicine for the treatment of cognitive disorders. Forty drugs were selected from authoritative written documents of Iranian traditional medicine. Each drug was extracted by accelerated solvent extraction using dichloromethane followed by methanol. The 80 extracts were screened for AChE inhibitory activity by a TLC bioautography method. The inhibiting effect of the 32 most active extracts was measured by a microplate colorimetric assay. Due to the best activity, the seeds of Peganum harmala L. were investigated in detail. From the TLC bioautography assay the alkaloids harmaline and harmine were identified as active compounds. This result was confirmed by means of HPLC-DAD. The IC(50) values were 41.2 μg/mL for the methanol extract, 95.5 μg/mL for the dichloromethane extract, 8.4 μg/mL for harmaline and 10.9 μg/mL for harmine. The concentrations of active compounds in the extracts were determined by a fast and precise HPLC method. As the amounts of harmaline and harmine in the extracts were correlated with the IC(50) values of the extracts, it can be concluded that these two alkaloids are responsible for the AChE inhibitory activity of P. harmala.

Catechol alkenyls from Semecarpus anacardium: Acetylcholinesterase inhibition and binding mode predictions

“…Detection was performed with anisaldehyde-sulfuric acid reagent to determine the chemical composition of the extract. In addition, a TLC bioautography screening assay was performed for AChE inhibitory activity according to a published method under use of the same stationary and mobile phase and very thorough removal of the mobile phase under airstream before detection (Marston et al, 2002;Adhami et al, 2011). Chelidonine served as a positive control showing Rf 0.45 in this system.…”

“…Pharmacological studies have shown several biological activities for Semecarpus anacardium such as anti-inflammatory (Bhitre et al, 2008), antiatherogenic (Sharma et al, 1995), anti-oxidant (Pal et al, 2008), anti-microbial (Gajjar et al, 2009), hypoglycemic (Kothai et al, 2005), hypolipidemic (Jaya et al, 2010), anti-carcinogenic (Nair et al, 2009) and anti-spermatogenic effects (Sharma et al, 2003). Methanolic and dichloromethane (DCM) extracts from the fruit resin of Semecarpus anacardium were among the most potent hits for AChE inhibition in a screening of plants used for the enhancement of cognitive performance and treatment of memory loss in ITM (Adhami et al, 2011). In this study, an activity-guided approach was applied to isolate and characterize the components with AChE inhibitory activity.…”

Fast determination of harmala alkaloids in edible algae by capillary electrophoresis mass spectrometry

“…Harmala alkaloids (HAlks) are a family of compounds with pharmacological and psychopharmacological effects on humans [1][2][3][4]. They are especially renowned for their antidepressant properties, because they are strong inhibitors of monoamine oxidase type A (MAO-A) enzyme, which catalyzes the oxidative deamination of biogenic amines and neurotransmitters [2][3][4].…”

Establishment of an effective TLC bioautographic method for the detection ofMycobacterium tuberculosisH37Ra phosphoglucose isomerase inhibition by phosphoenolpyruvate

“…In our opinion, there is a clear trend towards the use of the TLC bioautography technique as a method for screening active compounds against microorganisms rather than a method for the detection of enzyme activities or inhibitors. The use of TLC (bio)autography was reported for the screening of inhibitors of acetylcholinesterase [12][13][14][15][16][17][18][19][20][21][22][23][24][25][26] , butyrylcholinesterase 12,16,22,23,27 , dipeptidyl peptidase IV 28 , glucose-6-phosphate dehydrogenase 29 , a-and b-glucosidases [30][31][32][33][34] , lipase [35][36][37] , monoamine oxidases A and B 38,39 , DNA topoisomerase I 40 , tyrosinase [41][42][43] and xanthine oxidase 44 . To date, the use of the TLC-based autographic method for the detection of PGI inhibition has only been developed for a biocatalyst isolated from the reference E. coli strain ATCC (American Type Culture Collection) 25922 45 .…”