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Influence of Hypericum perforatum extract and its single compounds on amyloid-beta mediated toxicity in microglial cells.
Life Sci. 81, 884-894 (2007)
As immunocompetent cells of the brain, microglia are able to counteract the damaging effects of amyloid-beta in Alzheimer's disease by phagocytosis-mediated clearance of protein aggregates. The survival and health of microglia are therefore critical for attenuating and preventing neurodegenerative diseases. In a microglial cell line pretreated with St. John's wort (Hypericum perforatum L.) extract (HPE), the cell death evoked by treatment with amyloid-beta (25-35) and (1-40) was attenuated significantly in a dose-dependent manner. Investigation of the single compounds in the extract revealed that the flavanols (+)-catechin and (-)-epicatechin increase cell viability slightly, whereas the flavonol quercetin and its glycosides rutin, hyperosid and quercitrin showed no effect on cell viability. In contrast, at the same concentration, the flavonoids reduced the formation of amyloid-induced reactive oxygen species in microglia, indicating that improvement of cell viability by the catechins is not correlated to the antioxidant activity. No influence of HPE on the capacity of microglia to phagocytose sub-toxic concentrations of fibrillar amyloid-beta (1-40) was observed. Other experiments showed that HPE, (+)-catechin and (-)-epicatechin can alter cellular membrane fluidity and thereby may have a beneficial effect on cell health. Our findings provide in vitro evidence that treatment especially with the complex plant extract HPE may restore or improve microglial viability and thereby attenuate amyloid-beta mediated toxicity in Alzheimer's disease.
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Publikationstyp
Artikel: Journalartikel
Dokumenttyp
Wissenschaftlicher Artikel
Schlagwörter
Hypericum perforatum; St. John's wort; Microglia; Amyloid beta; Reactive oxygen species; Catechin; Epicatechin; Membrane fluidity; Phagocytosis
ISSN (print) / ISBN
0024-3205
e-ISSN
1879-0631
Zeitschrift
Life Sciences
Quellenangaben
Band: 81,
Heft: 11,
Seiten: 884-894
Verlag
Elsevier
Nichtpatentliteratur
Publikationen
Begutachtungsstatus
Peer reviewed
Institut(e)
Institute of Virology (VIRO)