Poster Topical Area: Dietary Bioactive Components

Location: Hall D

Poster Board Number: 373

P08-115 - Combined neuroprotective effect of melatonin, protocatechuic acid and hydroxytyrosol on alpha-synuclein fibril formation

Monday, Jun 11
8:00 AM – 3:00 PM

Objective
Abnormal aggregates of α-synuclein (αsyn) in the brain are considered a relevant physiopathological feature of Parkinson’s disease (PD) (1). Food bioactive compounds are being intensively scrutinized as potential preventive agents against PD. Recent research has demonstrated a potent effect against αsyn aggregation and toxicity by melatonin (MEL), protocatechuic acid (PCA) and hydroxytyrosol (HT) (2, 3, 4), which are present in a variety of plant foods. Hence, following the consumption of a balanced diet, significant plasma concentration can be reached for these compounds (5). The hypothesis of this study is if these molecules have an individual inhibitory effect on αsyn aggregation, the combination of them could even enhance the neuroprotective effect. Therefore, the objective of this work is to evaluate the in vitro inhibitory effects of MEL, PCA and HT and their combinations on αsyn fibril formation in order to ascertain their combined dietary effect .

Methods

αsyn fibril formation monitorization using Thioflavin T (ThT)
MEL (250 μM), PCA (100 μM), HT (100 μM), MEL+PCA, MEL+HT, PCA+HT and MEL+PCA+HT were incubated with or without αsyn protein (70 µM) and ThT (25 µM) during 142 h under continuous starring, 37ºC and 1000 rpm. Fluorescence data were recorded every 2h.

Transmission Electronic Microscopy (TEM)
ThT assay resulting samples were placed on carbon-coated Formvard grid, incubated and viewed using a TEM (80 kV).

Electrophoresis and staining.
ThT samples were diluted with of loading buffer and boiled at 50°C for 3 minutes. Then were loaded on 4−20% Tris−glycine gel and finally were stained with Coomassie Blue.

Results

As can be observed in Figure 1 and Table 1, MEL, PCA and HT (250, 100 and 100 µM, respectively) alone, have an inhibitory effect on αsyn fibril formation presenting a percentage of inhibition of 8.5, 76.3 and 80.9 %, respectively. MEL shows negligible effect either isolated or combined. The best results are obtained with the polyphenols PCA+HT (87.5%). TEM and electrophoresis images confirm the obtained results (Figure 2).

Conclusion
In summary, this work has demonstrated a discrete combined effect mostly for PCA and HT, which could be reached with the intake of virgin olive oil and red fruits. NMR studies are necessary to explain the structure-activity relation that explains these results.



Funding Source: Spanish Government for its financial assistance (Projects MICINN AGL2013-47300-C3-2-R and MICINN AGL2016-77505-C3-2-R).


CoAuthors: Ana M. Troncoso, PhD – Professor of Nutrition and Food Science, Universidad de Sevilla; Ruth Hornedo-Ortega, PhD – Universidad de Sevilla; Marta Gallardo-Fernandez, Master – Universidad de Sevilla; MªCarmen Garcia-Parrilla, Full professor – Universidad de Sevilla

Ana Belen Cerezo Lopez

Universidad de Sevilla