Neurodegenerative diseases, among which one of the most common is Alzheimer’s disease, are a multifactorial disease and therefore demand multiple therapeutic approaches. In the last few years, different active constituents from plants have been tested as potential drugs in neurodegenerative disease therapy. The availability, lower price and less toxic effects of herbal medicines compared with synthetic agents make them a simple and excellent choice in the treatment of neurodegenerative diseases. The empirical approach to discovering new drugs from the systematic screening of plant extracts or plant-derived compounds is still an important strategy when it comes to finding new biologically active substances.
The determination of acetylcholinesterase activity inhibition by anthocyanin from blueberry and purple potato extracts was performed by HPLC [33]. The procedure was based on an Ellman reaction performed before HPLC-DAD analysis. The chromatographic analysis was performed on a C18 column thermostated at 37 °C with mobile phase containing methanol–water–triethylamine (40:60:0.05, v/v/v). For the optimization of the experiment conditions, the effect of pH on enzyme activity, reaction temperature on enzyme activity, reaction time on enzyme activity, and acetylthiocholine iodide and acetylcholinesterase concentration on enzyme activity were investigated [33]. The authors recommended the HPLC method especially for the evaluation of the acetylcholinesterase inhibitory activity in samples with deep color.
Lupeol long-chain alkanoic ester, lupeol β-hydroxy fatty acid esters 2c,d (laevigatins I and II) and lupeol and lupeol acetate isolated from the latex of Periploca laevigata were tested for acetylcholinesterase inhibition activity [34]. Methanol extract exhibited anti-acetylcholinesterase activity with IC50 = 60.90 μg/mL. The highest inhibition activity was observed for lupeol with IC50 = 38.31 μg/mL. The results obtained by the authors suggest that the triterpenic skeleton and the free secondary alcohol function at C-3 could be responsible of this activity, while the esterification of the alcohol function may decrease the inhibition of acetylcholinesterase [34].
Cyclohexanoids namely, speciosin U, speciosin V and speciosin W from the endophytic fungus Saccharicola sp. showed acetylcholinesterase inhibitory activities comparable to reference inhibitor galantamine [7]. The IC50 value obtained for the most active compound speciosin U were 0.037 mg/mL and 0.026 mg/mL against acetylcholinesterase from human erythrocytes and from Electrophorus electricus, respectively. In the same experiments, the IC50 values obtained for galantamine were 0.076 and 0.0047 mg/mL against acetylcholinesterase from human erythrocytes and from Electrophorus electricus, respectively. The obtained results indicated that Speciosin U possessed higher in vitro inhibitory activity, comparable to the reference inhibitor galantamine against acetylcholinesterase from human erythrocytes. Therefore, the compound may be a good candidate for further in vitro and in vivo investigations.
This entry is adapted from the peer-reviewed paper 10.3390/molecules27103222