Researchers from Malta and France fed extracts of the plants to transgenic flies engineered to express both late- and early-onset Alzheimer’s disease, as well as Parkinson’s disease – along with non-modified flies.
While the prickly pear (EOFI) and seaweed (EPP) extracts had no effect on the lifespan or motility of normal flies, the researchers found the extracts could improve both factors for the transgenic flies, compared to control groups.
Different effects for late and early Alzheimer’s
Flies with the Aβ42 transgene – expressing as late-onset Alzheimer’s – showed no effect when fed EOFI extract.
“In contrast, flies fed EPP throughout adulthood showed a significant increase in lifespan compared to flies in the control group (p = 0.0033). In this respect, EPP exposed flies had a median lifespan of 46 days compared to 44 days in control flies,” wrote the researchers in a paper published in Neuroscience Letters.
The reverse was true for flies with the Arctic Aβ42 transgene, which manifests as early-onset Alzheimer’s: “We observed that although EPP increased median lifespan from 29 to 31 days, overall change in lifespan was not statistically significant. Strikingly, we show that EOFI supplementation had a dramatic impact on the lifespan of flies expressing Arctic Aβ42 (p = 0.0005). Consequently, the median lifespan is shifted from 29 days to 33 days upon treatment with EOFI.”
Consuming the extracts also helped flies’ motility, with EOFI improving climbing ability in a controlled situation from 48% to 67% of wild-type flies’ capacity to climb for subjects with Arctic Aβ42 flies, and EPP boosting week four climbing ability from 29% to 46% with regular Aβ42 flies.
Researchers also tested both compounds on flies engineered to express Parkinson’s disease, and found both EOFI and EPP could shift the median lifespan of the flies by a day.
Effects comparable to black tea extract
To test the effectiveness of the extracts on disrupting the action of the Aβ42 and α-syn oligomers which cause the expression of Alzheimer’s and Parkinson’s respectively, the researchers tested them alongside black tea extract (BTE) as a positive control. They tested the ability of the Aβ42 and α-syn compounds to permeate membranes as a way of testing how they would affect cells in the body.
“In case of Aβ42, either extract was allowed to interact with 1 μM pre-aggregated Aβ42 before adding to the liposomes, an approach that favours destabilisation of the toxic oligomers. We find that EPP or EOFI supplementation protected against lipid vesicle disruption by the membrane-active oligomeric species,” wrote the authors.
“Compared to BTE, which is a strong inhibitor of membrane permeabilisation, EOFI and EPP had a mild-to-moderate effect,” they added.
In the case of α-syn, both EOFI and to a larger extent EPP interfered with α-syn-induced membrane perturbation to levels comparable to those of BTE, according to the authors.
They speculated that as EPP was most effective against late-onset Alzheimer’s, with the disease-modifying ability most pronounced later in the adult life of the flies, the extract showed poor bioavailability and required repeated doses over time to be effective.
In contrast, they speculated that EOFI had better bioavailability, and was possibly more effective in situations with heightened levels of cellular stress, as it was most effective against early-onset Alzheimer’s.
They suggested future research should focus on exploring the use of these plant extracts in drugs to combat neurodegenerative diseases.
Source: Neuroscience Letters
Published online ahead of print, doi: 10.1016/j.neulet.2016.11.058
“Extracts from two ubiquitous Mediterranean plants ameliorate cellular and animal models of neurodegenerative proteinopathies”
Authors: Briffa, M; Ghio, S, et al.