The development of biomaterials with intrinsic antioxidant properties could represent a valuable strategy for preventing the onset of peri-implant diseases. In this context, quercetin, a naturally occurring flavonoid, has been entrapped at different weight percentages in a silica-based inorganic material by a sol–gel route. The establishment of hydrogen bond interactions between the flavonol and the solid matrix was ascertained by Fourier transform infrared spectroscopy. This technique also evidenced changes in the stretching frequencies of the quercetin dienonic moiety, suggesting that the formation of a secondary product occurs. Scanning electron microscopy was applied to detect the morphology of the synthesized materials. Their bioactivity was shown by the formation of a hydroxyapatite layer on sample surface soaked in a fluid that simulates the composition of human blood plasma. When the potential release of flavonol was determined by liquid chromatography coupled with ultraviolet and electrospray ionization tandem mass spectrometry techniques, the eluates displayed a retention time that was 0.5 min less than quercetin. Collision-activated dissociation mass spectrometry and untraviolet-visible spectroscopy were in accordance with the release of a quercetin derivative. The antiradical properties of the investigated systems were evaluated by DPPH and ABTS methods, whereas the 2,7-dichlorofluorescein diacetate assay highlighted their ability to inhibit the H2O2-induced intracellular production of reactive oxygen species in NIH-3T3 mouse fibroblast cells. Data obtained, along with data gathered from the MTT cytotoxicity test, revealed that the materials that entrapped the highest amount of quercetin showed notable antioxidant effectiveness.

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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.

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The development of polyphenol neuroprotective nutraceuticals useful for functional foods could be a valuable strategy for counteracting oxidative stress relative diseases as Alzheimer's Disease (AD). Oxidative stress is one of the AD earliest event and seems to play a central role in Aβ generation, neuroinflammation, and neuronal apoptosis. 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 plant drugs could represent an alternative and valid approach. In this context, an alcoholic extract (Pl-M) from deterpenated Pistacia lentiscus L. leaves was investigated for its phenol composition through LC-ESI-MS/MS analysis. Besides the identified metabolites, ten compounds were reported for the first time as constituents of Pistacia lentiscus leaves. Through DPPH, ABTS, and ORAC methods, the antioxidant potential of the extract was initially investigated. In order to evaluate the preparation of a safe and no toxic extract, 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. Evaluating the protective effects from oxidant injury in SK-N-BE(2)-C cells cotreated with the plant complex and H2O2, or Aβ(25-35) fragment, it was observed that Pl-M extract exerted a significant cytoprotective response in both the oxidized cell systems. In particular, Pl-M extract was able to reduce by nearly 50% the Aβ(25-35) induced toxicity at 25.0 μg/mL dose level, whereas it counteracted almost completely the cytotoxic action at 100.0 μg/mL. Data obtained allow us to hypothesize the use of Pistacia lentiscus leaves, a broadly available and renewable source, as an alternative strategy for the enrichment of food matrices with polyphenol bioactives. The present study put the basis for bioavailability and preclinical studies, able to define Pl-M extract safety and efficacy.