title: Capsicum annuum var. grossum (Bell Pepper) Inhibits β-Secretase Activity and β-Amyloid1-40Aggregation.
abstract: The deposition of amyloid protein as senile plaques is the major signature of Alzheimer's disease (AD). It is produced by the sequential cleavage of the amyloid precursor protein by secretases. Moreover, peppers are noted for their antiaging and cognitive enhancing properties. Thus, in this study, the effects of polyphenol-rich extracts from bell pepper on amyloid production and aggregation in vitro were investigated. Bell pepper (ripe and unripe) was extracted with methanol-1 N HCl (1:1 v/v). Thereafter, the inhibitory potentials of the extracts on β-secretase and β-amyloid1-40aggregation were determined. Phenolic composition of the pepper fruits was further determined by HPLC-DAD (high performance liquid chromatography-diode array detector). There was a dose-dependent inhibition of β-secretase by the pepper fruits with the ripe fruits (2.17 ± 0.17 μg/L) showing a significantly (P < .05) higher inhibitory effect than the unripe (3.44 ± 0.11 μg/L). Furthermore, Thioflavin-T and transmission electron microscopy analyses revealed that phenolic extracts from pepper fruits (1 and 10 μg/L) could counteract the initial aggregation of Aβ1-40, as well as prevent further aggregation preformed fibrils. These inhibitory activities could be attributed to the predominant presence of phenolic constituents in the pepper fruits. It is possible to conclude that bell pepper could be a possible dietary intervention into the management of AD.
authors.affiliation: 1 Department of Biochemistry and Molecular Biology, Obafemi Awolowo University , Ile Ife, Nigeria .|2 Department of Functional Food, Nutraceuticals and Phytomedicine Unit, Department of Biochemistry, Federal University of Technology , Akure, Nigeria .|3 Department of Life Sciences, University of Trieste , Trieste, Italy .
authors.forename: Omodesola Oluwafisayo
authors.initials: OO
authors.lastname: Ogunruku
authors.affiliation: 2 Department of Functional Food, Nutraceuticals and Phytomedicine Unit, Department of Biochemistry, Federal University of Technology , Akure, Nigeria .
authors.forename: Ganiyu
authors.initials: G
authors.lastname: Oboh
authors.affiliation: 3 Department of Life Sciences, University of Trieste , Trieste, Italy .
authors.forename: Sabina
authors.initials: S
authors.lastname: Passamonti
authors.affiliation: 3 Department of Life Sciences, University of Trieste , Trieste, Italy .
authors.forename: Federica
authors.initials: F
authors.lastname: Tramer
authors.affiliation: 4 Program of Post-Graduation in Pharmaceutical Sciences, Federal University of Santa Maria , Santa Maria, Brazil .
authors.forename: Aline Augusti
authors.initials: AA
authors.lastname: Boligon
mesh_terms: D000544:Alzheimer Disease / Q000201:enzymology* / Q000378:metabolism; D053829:Amyloid Precursor Protein Secretases / Q000037:antagonists & inhibitors* / Q000737:chemistry / Q000378:metabolism; D016229:Amyloid beta-Peptides / Q000737:chemistry* / Q000378:metabolism; D002212:Capsicum / Q000737:chemistry*; D004791:Enzyme Inhibitors / Q000737:chemistry*; D006801:Humans; D007700:Kinetics; D010446:Peptide Fragments / Q000737:chemistry* / Q000378:metabolism; D010936:Plant Extracts / Q000737:chemistry*; D066329:Protein Aggregates
chemical_list: D016229:Amyloid beta-Peptides; D004791:Enzyme Inhibitors; D010446:Peptide Fragments; D010936:Plant Extracts; D066329:Protein Aggregates; C078592:amyloid beta-protein (1-40); D053829:Amyloid Precursor Protein Secretases
keywords: Alzheimer's disease; Capsicum spp; bell pepper; neurodegeneration; β-amyloid1–40; β-secretase