Planta Med 2015; 81(05): 357-362
DOI: 10.1055/s-0035-1545724
Biological and Pharmacological Activity
Original Papers
Georg Thieme Verlag KG Stuttgart · New York

Extracts of Glycyrrhiza uralensis and Isoliquiritigenin Counteract Amyloid-β Toxicity in Caenorhabditis elegans

Pille Link
1   Institute of Pharmacy and Molecular Biotechnology, Heidelberg University, Heidelberg, Germany
,
Bernhard Wetterauer
1   Institute of Pharmacy and Molecular Biotechnology, Heidelberg University, Heidelberg, Germany
,
Yujie Fu
2   Key Laboratory of Forest Plant Ecology, Ministry of Education, Northeast Forestry University, Harbin, China
,
Michael Wink
1   Institute of Pharmacy and Molecular Biotechnology, Heidelberg University, Heidelberg, Germany
› Author Affiliations
Further Information

Publication History

received 04 November 2014
revised 26 January 2015

accepted 29 January 2015

Publication Date:
17 March 2015 (online)

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Abstract

Alzheimerʼs disease is a rising threat for modern societies as more and more people reach old age. To date, there is no effective treatment for this condition. In this study, we investigated the potential of Glycyrrhiza uralensis to counteract amyloid-β toxicity, one of the key features of Alzheimerʼs disease. An LC-MS/MS analysis revealed glycyrrhizic acid and glycosylated forms of isoliquiritigenin and liquiritigenin as major constituents of water and methanol extracts of G. uralensis. These extracts and the pure compounds were tested for their activity in two Caenorhabditis elegans models of amyloid-β aggregation and amyloid-β toxicity, respectively. The number of amyloid-β aggregates decreased by 30 % after treatment with isoliquiritigenin, the methanol extract could reduce the number by 14 %, liquiritigenin and glycyrrhizic acid by 15 %, and the aglycon of glycyrrhizic acid, glycyrrhetinic acid, by 20 %. Both extracts and isoliquiritigenin also showed significant activity against acute amyloid-β toxicity in transgenic C. elegans that express human amyloid-β peptides, delaying the paralysis in this model by 1.8 h and 1.1 h, respectively. We conclude that secondary compounds of G. uralensis may become interesting drug candidates for the treatment of Alzheimerʼs disease, which, however, need further analysis in other model systems.