title: Neuroprotective potential of Laurus nobilis antioxidant polyphenol-enriched leaf extracts.
abstract: Oxidative stress has been proposed to be an important factor in the pathogenesis of Alzheimer's disease (AD), playing a central role in amyloid β-protein (Aβ) generation and neuronal apoptosis. Oxidative damage directly correlates with the presence of Aβ deposits. Aβ and oxidative stress jointly induce neuronal death, Aβ deposits, gliosis, and memory impairment in AD. In order to counteract AD neurodegeneration, the inhibition of the vicious cycle of Aβ generation and oxidation is an attractive therapeutic strategy, and antiamyloidogenic and antioxidant herbal drugs could represent an alternative and valid approach. In this context, an alcoholic extract from Laurus nobilis leaves (LnM) and seven fractions obtained therefrom were of interest. All extracts prepared through extractive and chromatographic techniques were phytochemically studied by chromatographic techniques including gas chromatography-mass spectrometry (GC-MS) and liquid chromatography-tandem mass spectrometry (LC-MS(n)). The potential antioxidant efficacy of the obtained fractions was screened by DPPH(•) and ABTS(•+) assays, as well as specific assay media characterized from the presence of highly reactive ROS and RNS species (ROO(•), OH(•), O2(•-), and NO). In order to evaluate the preparation of safe and nontoxic extracts, MTT, SRB, and LDH assays toward SH-5YSY and SK-N-BE(2)-C human neuronal cell lines, as well as on C6 mouse glial cell line, were performed. The apoptosis-inducing properties by spectroscopic evaluation of the extracts' ability to activate caspase-3 and by a DNA fragmentation assay were also investigated. Data thus obtained allowed us to state the absence of toxic effects induced by phenolic-rich fractions (LnM, LnM-1, LnM-1a, LnM-1b, and LnM-2c), which at the same time exerted significant cytoprotective and antioxidant responses in hydrogen peroxide and Aβ(25-35)-fragment-oxidized cell systems. The potential antiamyloidogenic efficacy of Laurus nobilis leaf polar extracts in the Aβ(25-35) fragment oxidized cell systems was further analyzed by Congo red staining.
authors.affiliation: Department of Environmental Biological and Pharmaceutical Sciences and Technologies, Second University of Naples , Via Vivaldi 43, I-81100 Caserta Italy.
authors.forename: Severina
authors.initials: S
authors.lastname: Pacifico
authors.forename: Marialuisa
authors.initials: M
authors.lastname: Gallicchio
authors.forename: Peter
authors.initials: P
authors.lastname: Lorenz
authors.forename: Sarina M
authors.initials: SM
authors.lastname: Duckstein
authors.forename: Nicoletta
authors.initials: N
authors.lastname: Potenza
authors.forename: Silvia
authors.initials: S
authors.lastname: Galasso
authors.forename: Sabina
authors.initials: S
authors.lastname: Marciano
authors.forename: Antonio
authors.initials: A
authors.lastname: Fiorentino
authors.forename: Florian C
authors.initials: FC
authors.lastname: Stintzing
authors.forename: Pietro
authors.initials: P
authors.lastname: Monaco
mesh_terms: D000975:Antioxidants / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D045744:Cell Line, Tumor; D002851:Chromatography, High Pressure Liquid; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D027442:Laurus / Q000737:chemistry*; D018696:Neuroprotective Agents / Q000494:pharmacology*; D010936:Plant Extracts / Q000494:pharmacology*; D018515:Plant Leaves / Q000737:chemistry*; D059808:Polyphenols / Q000494:pharmacology*; D017382:Reactive Oxygen Species / Q000378:metabolism; D021241:Spectrometry, Mass, Electrospray Ionization; D053719:Tandem Mass Spectrometry
chemical_list: D000975:Antioxidants; D018696:Neuroprotective Agents; D010936:Plant Extracts; D059808:Polyphenols; D017382:Reactive Oxygen Species