CARLINA ACAULIS HAS ANTIOXIDANT EFFECTS AND AMELIORATES BETA-AMYLOID TOXICITY IN A C. ELEGANS MODEL

Abstract

Background: One of the key proteins in the pathology of Alzheimer’s disease is beta-amyloid. Oligomers of this peptide can damage neurons by different actions including oxidative stress. Carlina acaulis is a long known medicinal plant with antimicrobial and antioxidant activities. The main active compound of this plant is carlina oxide found in the essential oil. The objective of this work is to study the effects of Carlina acaulis and carlina oxide on beta-amyloid toxicity in a C. elegans model system. Methods: A dichlormethane extract of Carlina acaulis, carlina oxide isolated from this extract and the extract without carlina oxide were tested for their activity against beta-amyloid toxicity and antioxidative effects. For the former a transgenic C. elegans strain expressing human beta-amyloid in its muscle cells was used and the paralysis was scored as a measure for beta-amyloid toxicity. The antioxidant activity was observed in another strain with a hsp16.2::GFP construct. Results: The antioxidative activity was confirmed in the C. elegans model. Carlina extract and carlina oxide both reduced the expression of heat shock proteins that was triggered by oxidative stress in a concentration dependant manner. The extract without carlina oxide failed to induce this effect. The extract also had an ameliorating effect on the beta-amyloid toxicity, but the extract without carlina oxide and carlina oxide alone did not show the expected effect. Conclusions: From this data we can conclude that the antioxidative incredient of Carlina acaulis is carlina oxide, as the residual extract showed no antioxidant activity. The extract also showed an effect against beta-amyloid toxicity, but this cannot be contributed to the antioxidant activity of carlina oxide alone. In fact neither this compound nor the residual extract showed an effect comparable to this of the whole extract, suggesting synergistic effects between carlina oxide and the other constituents of the extract.