Search results for "chimica"
showing 10 items of 4450 documents
Theoretical Determination of the pK a Values of Betalamic Acid Related to the Free Radical Scavenger Capacity: Comparison Between Empirical and Quant…
2015
Health benefits of dietary phytochemicals have been suggested in recent years. Among 1000s of different compounds, Betalains, which occur in vegetables of the Cariophyllalae order (cactus pear fruits and red beet), have been considered because of reducing power and potential to affect redox-modulated cellular processes. The antioxidant power of Betalains is strictly due to the dissociation rate of the acid moieties present in all the molecules of this family of phytochemicals. Experimentally, only the pK a values of betanin were determined. Recently, it was evidenced it was evidenced as the acid dissociation, at different environmental pHs, affects on its electron-donating capacity, and fur…
Ionic liquid gels and antioxidant carbon nanotubes: Hybrid soft materials with improved radical scavenging activity
2019
Hypothesis: Performances of materials are frequently affected by the action of radicals that can induce their degradation. To overcome the above issue, natural antioxidants (AOs) can be added during manufacturing. Considering the high instability of AOs, they have been adsorbed on carbon nanomaterials surface. However, the inclusion of functionalized carbon nanomaterials into gel matrix could enhance the antioxidant efficiency and represent an easy way to disperse and handle the active species.Experiments: Carboxypropyl functionalized carbon nanotubes (f-CNT), pure or with physically adsorbed alpha-tocopherol (f-CNT-VE) and quercetin (f-CNT-Q), were incorporated in some ionic liquid gels (I…
Nanosponges for the protection and release of the natural phenolic antioxidants quercetin, curcumin and phenethyl caffeate
2020
The inclusion of polyphenols into nanoporous materials may significantly improve their application as radical trapping agents for therapeutic purposes. In the present work, nanosponges based on hypercross- linked cyclodextrins and calixarenes (NS1–NS3) were used as carriers of three natural phenolic antioxidants: quercetin (Que), curcumin (Cur) and phenethyl caffeate (Phec). Good w/w loadings, namely 7.3% for the Que–NS1 composite, 17.3% for Cur–NS2 and 12.9% for Phec–NS3, were achieved. The release kinetics and the inhibition rate constants (kinh) of the reaction with alkylperoxyl radicals (ROO.) in 0.1 M phosphate buffer solutions at pH 7.4 were studied and indicated better antioxidant ac…
Polyphenols pattern and correlation with antioxidant activities of berries extracts from four different populations of SicilianSambucus nigraL.
2014
Sambucus nigra L. (Caprifoliaceae) is wide spread in temperate and sub-tropical zones. The consumption of its berries has been associated with health benefits especially for its high content of natural antioxidants such as polyphenols, in particular anthocyanins. In this work we investigated the polyphenolic composition and the in vitro antioxidant activities (ABTS, DPPH, BCB and FRAP-ferrozine (FRAP-FZ) assays) of S. nigra berries, collected in four different Sicilian areas (Italy). Elderberries are considered one of the fruits with highest anthocyanins content, the amount of phenolic compounds, other than anthocyanins, is approximately 1.5 times greater than the latter. The LC–MS analyses…
Antioxidant activity and fatty acids quantification in Sicilian purslane germplasm
2019
Portulaca oleracea is an annual succulent herb in the family Portulacaceae. It is a nutritious vegetable with high antioxidant properties and, it is among the richest plant source of ω-3 fatty acids, as well as a rich source of ω-6 fatty acids, ascorbic acid, tocopherols and beta-carotene. In the present study, three purslane populations under different Mediterranean environmental conditions for two years, for future valorization as novel food sources of omega-3 fatty acids, were evaluated. In particular, biomorphological characteristics, total phenols and fatty acids content were determined. The antioxidant activities were evaluated using 2,2-diphenyl-1-picrylhydrazyl assay. The population…
Omega-3 rich foods: Durum wheat spaghetti fortified with Portulaca oleracea
2020
Abstract Portulaca oleracea is an annual succulent herb (purslane) with high antioxidant properties and high content of essential ω-3 and ω-6 fatty acids, ascorbic acid, α-tocopherol and β-carotene. In the present study, sensorial and chemical analyses of uncooked and cooked durum wheat pasta fortified with purslane from three different Sicilian areas and at three different concentrations (5, 10 and 15%) were estimated. The sensorial analysis showed that the scores of the overall acceptance decreased considerably in pasta with 15% purslane, while consumers appreciated pasta samples with 10% purslane. Chemical analysis highlighted that the addition of purslane gave pasta samples the potentia…
In vitro digestion of betalainic foods. Stability and bioaccessibility of betaxanthins and betacyanins and antioxidative potential of food digesta.
2008
Betalains are considered to be bioactive dietary phytochemicals. The stability of betacyanins and betaxanthins from either fresh foods or manufactured products of cactus pear fruit ( Opuntia ficus indica L. Mill. cv. Gialla and Rossa) and red beet ( Beta vulgaris L. ssp. vulgaris) was assessed in a simulated oral, gastric, and small intestinal digestion and compared with the digestive stability of purified pigments. A minor loss of indicaxanthin, at the gastric-like environment only, and a decrease of vulgaxanthin I through all digestion steps were observed, which was not affected by food matrix. In contrast, food matrix prevented decay of betanin and isobetanin at the gastric-like environm…
Betacyanins as phenol antioxidants. Chemistry and mechanistic aspects of the lipoperoxyl radical-scavenging activity in solution and liposomes.
2009
Reaction kinetics of betanin and its aglycone betanidin towards peroxyl radicals generated from the azo-initiated oxidation of methyl linoleate in methanol, and of a heterogeneous aqueous/soybean phosphatidylcholine liposomal system, were studied by monitoring formation of linoleic acid hydroperoxides and consumption of the pigments. Betanin was a weak retarder in methanol, and an effective chain breaking antioxidant in the liposomal model, indicating that kinetic solvent effects and partition in lipid bilayers may affect its activity. Betanidin behaved as a chain terminating antioxidant in both models. Kinetic parameters characterizing peroxyl radical-scavenging activity showed that betani…
Synthesis and antiproliferative activity of a natural like glucosyl polycyclic compound
2014
A new polycylic compound was synthesized and evaluated for its antiproliferative activity against the NCI panel of human tumoral cell lines showing IC50 values in the range 0.47-5.43 µM. The compound induced a decrease of the level of cyclin B1, whereas increased the level of the inhibitor p21 WAF1
Synthesis of the new ring system 6,8-dihydro-5H-pyrrolo[3,4-h]quinazoline
2009
Abstract A convenient synthesis of the pyrrolo[3,4- h ]quinazoline ring system is reported. Our synthetic approach consisted of the annelation of a pyrimidine ring to an isoindole moiety using tetrahydroisoindole-4-ones as building blocks. The antiproliferative activity of the new compounds was investigated and one of them showed antitumor activity against all the 59 tested cell lines at micromolar concentrations (1.46–18.4 μM).