Sideritis scardica Griseb. is one of over 150 species of the genus Sideritis L. (Lamiaceae) and endemic
to the Balkan peninsula, where it is traditionally used as tea. Recent studies show
an activity of S. scardica extracts in the CNS in vitro and in vivo. An influence on the reuptake of monoamine neurotransmitters [1], a stimulating effect
on EEG patterns in rats [2] and a cognition enhancing activity in mice [3] have been
reported. To further investigate CNS effects of the plant we used the nematode Caenorhabditis elegans, a well investigated model organism, to explore the influence of four S. scardica extracts of different polarity (H2O; 20, 50, 70% EtOH) on characteristics of neurodegenerative diseases like Alzheimer's
and Parkinson's in vivo. Deposits of human β-amyloid formed by the transgenic C. elegans strain CL2006 were stained with thioflavin S and counted. All groups treated with
S. scardica showed a significant lower number of plaques (max. 21% reduction vs. control). Furthermore,
the extracts were examined concerning an alleviation of Aβ-oligomer-induced neurotoxicity
by observing paralysis progression of strain Cl4176. Treated worms paralyzed significantly
later with a delay of the PT50 value of max. 9% vs. control. Additionally, we included human α-synuclein, a histopathological
hallmark of dementia, which is expressed by C. elegans strain NL5901. It is fused to the yellow fluorescent protein enabling to observe
and quantify its aggregation. Here the treated groups showed significant lower fluorescence
intensity (max. 37% reduction vs. control). In all assays S. scardica showed a dose-dependent effect influenced by the extraction medium (most potent 50%
EtOH). The results confirm the potential of Sideritis scardica preparations for the treatment of neurodegenerative diseases.
References:
[1] Knörle R J Neural Transm 2012; 119: 1477 – 82
[2] Dimpfel W J Ethnopharmacol 2013; 149: 583 – 589
[3] Feistel B, Walbroel B, Pahnke J Planta Med 2013; 79: 1142 (79-PB9)
