Sideritis scardica extracts inhibit aggregation and toxicity of amyloid-β in Caenorhabditis elegans used as a model for Alzheimer's disease
- Published
- Accepted
- Subject Areas
- Cognitive Disorders, Drugs and Devices, Pharmacology
- Keywords
- Sideritis scardica, Lamiaceae, Caenorhabditis elegans, amyloid-β, neurodegenerative diseases, neuroprotection, Alzheimer, Greek mountain tea
- Copyright
- © 2017 Heiner et al.
- Licence
- This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, reproduction and adaptation in any medium and for any purpose provided that it is properly attributed. For attribution, the original author(s), title, publication source (PeerJ Preprints) and either DOI or URL of the article must be cited.
- Cite this article
- 2017. Sideritis scardica extracts inhibit aggregation and toxicity of amyloid-β in Caenorhabditis elegans used as a model for Alzheimer's disease. PeerJ Preprints 5:e3483v1 https://doi.org/10.7287/peerj.preprints.3483v1
Abstract
Background. Beyond its traditional uses in the Balkan area, Sideritis scardica (known as Greek mountain tea, Lamiaceae) is currently extensively investigated for its pharmacological activity in the central nervous system. Antidepressant, psychostimulating, cognition-enhancing and neuroprotective properties have been described. In this study, we tested hydroalcoholic extracts of S. scardica for their potential to counteract amyloid-β toxicity and aggregation, which plays a crucial role in the pathogenesis of Alzheimer's disease.
Methods. For this purpose, we have chosen the nematode Caenorhabditis elegans, which is used as a model organism for neurodegenerative diseases. The concentration of different polyphenols in extracts prepared from water, 20, 40, 50, and 70 % ethanol was analysed by HPLC. Additionally, polar and unpolar fractions were prepared from the 40 % ethanolic extract and phytochemically analysed.
Results. Essentially, the contents of all measured constituents increased with the lipophilicity of the extraction solvents. Treatment of transgenic C. elegans strains expressing amyloid-β with the extracts resulted in a reduced number of peptide aggregates in the head region of the worms and alleviated toxicity of amyloid-β, observable through the degree of paralysed animals. The mid-polar extracts (40 and 50 % ethanol) turned out be the most active, decreasing the plaque number by 21 % and delaying the amyloid-β-induced paralysis by up to 3.5 h. The more lipophilic extract fractions exhibited higher activity than the hydrophilic ones.
Discussion. Sideritis scardica extracts demonstrated pharmacological activity against characteristics of Alzheimer's disease also in C. elegans, supporting current efforts to assess its potential for the treatment of cognitive decline. The active principle as well as the mode of action needs to be investigated in more detail.
Author Comment
This is a submission to PeerJ for review.
Supplemental Information
Growth control of worms treated with the substances
The worms were treated with the highest used concentrations of the extracts and fractions. A reduced body length would point to toxic effects to the worms or antimicrobial properties against the food source of the worms (E. coli). All concentrations were deemed suitable
Raw data of A beta plaques
Single values (mean plaque number of 20-25 worms) of up to 4 independently performed experiments. Results: means, SEM, statistics
Raw data of paralysis assay
First sheet: Single values (median values obtained from Kaplan-Meier analysis) of 4 independently performed experiments. Results: means, SEM, statistics
Second sheet: % of worms (test strain CL4176 expressing A beta) not paralysed for every time point. Data used for creating the graphs
Third sheet: % of worms (control strain CL802 not expressing A beta) not paralysed for every time point. Worms were treated with the highest concentration of the respective extract/ fraction. As worms were not paralysing, the delayed paralysis of CL4176 can be attributed to A beta-counteracting effects of the test substances.