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Zantaz honey is a monofloral variety produced from the melliferous plant Bupleurum spinosum (Apiaceae), a shrub that grows mainly in the Atlas Moroccan Mountains. Determination of the polyphenol composition revealed that methyl syringate accounts for more than 50% of total polyphenols, which represents a very useful parameter for the characterization of this monofloral honey. Epicatechin, syringic acid and catechin are also abundant. Caco-2 and THP-1 cells were used for determination of antioxidant and antiproliferative activities in Zantaz honey, respectively. All six commercial samples that were used for these studies exhibited antioxidant activity and inhibited cell proliferation. Interestingly, these activities had a positive correlation mainly with the content in methyl syringate and gallic acid. The recognition of health promoting activities in Zantaz honey should increase its commercial value, which would have a positive economic impact on the poor rural communities of Morocco where it is produced., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Oxidative stress due to the excess of radical oxygen species (ROS) contribute to the development of different diseases. The use of antioxidants may prevent the development of these diseases by counteracting ROS levels. There is an increasing interest in natural antioxidants as they are safer for consumers than synthetic antioxidants. In this work, reducing power, free radical scavenging and cellular antioxidant activities of chickpea peptides fractions have been investigated. Peptide sequences included in fractions with antioxidant activity were identified. Main sequences, ALEPDHR, TETWNPNHPEL, FVPH and SAEHGSLH, corresponded to legumin, the main seed protein. Most peptides contained histidine, which has shown antioxidant activity. Two peptides also included tryptophan and phenylalanine, in which the phenolic group could also serve as hydrogen donor. These results show that legumin is a source of antioxidant peptides of high interest for food and pharmaceutical industries to develop new nutraceuticals and functional foods., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

The role of the peptides-phenolic compounds (PC) interaction on the antioxidant capacity profile (ACP) of protein hydrolysates from rapeseed (Brassica napus) was studied in 36 hydrolysates obtained from a PC-rich and PC-reduced protein substrate. The latent profile analysis (LPA), with data of seven in vitro methods and one assay for cellular antioxidant activity (CAA), allowed identifying five distinctive groups of hydrolysates, each one with distinctive ACP. The interaction of peptides with naturally present PC diminished in vitro antioxidant activity in comparison with their PC-reduced counterparts. However, CAA increased when peptides-PC interaction occurred. The profile with the highest average CAA (62.41 ± 1.48%), shown by hydrolysates obtained by using alcalase, shared typical values of Cu(2+)-catalysed β-carotene oxidation (62.41 ± 0.43%), β-carotene bleaching inhibition (91.75 ± 0.22%) and Cu(2+)-chelating activity (74.53 ± 0.58%). The possibilities for a sample to exhibit ACP with higher CAA increased with each unit of positively charged amino acids, according to multinomial logistic regression analysis., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

Proximate composition, fatty acids and amino acid profiles and nutritional (chemical score, protein digestibility, PDCAAS and mineral dialyzability) and antioxidant properties (TEAC, DPPH and power reduction) from Porphyra columbina were evaluated. Total dietary fiber (48.02 ± 1.13 g/100 g dry weight) and protein (24.61 ± 0.21 g/100 g dry weight) were the two most abundant components in this seaweed. The main saturated and unsaturated fatty acids were C16:0 and C20:5 (n-3), respectively. The limiting amino acid was tryptophan with a chemical score of 57%. Protein digestibility was 74.33 ± 3.0%. Porphyra columbina has high mineral content with good Na/K relationship and medium value of potential mineral accessibility (P, Ca and Zn dializability: 18.75 ± 0.01, 17.62 ± 0.16 and 16.70 ± 0.44, respectively). The highest antioxidant properties were obtained with an acetone/water extraction system. This work provides important information about chemical composition and nutraceutical new properties of P. columbina.

Bean protein isolate and phaseolin were hydrolysed using pepsin and pancreatin, and the resulting hydrolysates were filtered through a 1kDa cut-off membrane and fractionated by size exclusion chromatography. Three fractions corresponding to MW 0.7-1.0kDa, 0.43-0.7kDa and <0.43kDa (A1, A2, and A3 for protein isolate fractions, and B1, B2, and B3 for phaseolin fractions) were assayed for antioxidant and metal chelating activity and they were also subjected to amino acid and SDS-PAGE analysis. Fractions A1 and B1 had the highest copper chelating activity (78% and 82%, respectively), while iron chelating activity was the highest in fractions A1 and B3 (36% and 16%, respectively). Fractions A2 and B3 had the highest antioxidant activity as determined by inhibition of reducing power and β-carotene bleaching, while the highest ABTS radical scavenging activity was found in A3 and B3. Thus, fractions coming from the isolate and phaseolin had similar activities except for iron chelation, suggesting that phaseolin is the major contributor to the antioxidant and copper chelating activities of the hydrolysed protein isolate., (Crown Copyright © 2012. Published by Elsevier Ltd. All rights reserved.)

Background: Antioxidant and chelating activities were determined in protein hydrolysates that were produced by treating a protein isolate of a non-toxic genotype of Jatropha curcas with the protease preparation alcalase., Results: 50 min protein hydrolysate with a degree of hydrolysis of 31.7% showed highest antioxidant and chelating activity. These activities were also determined in six peptidic fractions that were separated by gel filtration chromatography of the 50 min hydrolysate. The lower-molecular-weight peptidic fractions had the highest antioxidant and chelating activities, which correlated with a higher content in antioxidant and chelating amino acids such as tyrosine and histidine., Conclusion: Results show that J. curcas represents a good source of bioactive peptides. This may be important for the revalorization of defatted J. curcas flour, a by-product resulting form oil extraction for biodiesel production. This is especially important in Third World and developing countries such as Mexico., (Copyright © 2011 Society of Chemical Industry.)

The consequences of oxidative stress on microsomal proteins were analyzed by studying their pyrrolization and the antioxidative activity of the modified proteins produced. The microsomal system consisted of freshly prepared trout muscle microsomes, which were oxidized in the presence of 5 microM Cu(2+), 1 mM Fe(3+)/5 mM ascorbate, or 1 mM Cu(2+)/10 mM H(2)O(2). Pyrroles on proteins were detected by forming Ehrlich adducts with p-(dimethylamino)benzaldehyde and by determination of epsilon-N-pyrrolylnorleucine (Pnl) by capillary electrophoresis. Their antioxidative activity was studied by testing two model pyrrolized proteins (dimeric and monomeric modified bovine serum albumin: DBSA and MBSA, respectively), which were produced in the reaction of BSA and 4,5(E)-epoxy-2(E)-heptenal. These proteins were assayed at a concentration of 10-40 microg/mL, which was selected because at this concentration both DBSA and MBSA had a concentration of Pnl similar to the Pnl concentration produced in oxidized microsomes. Both DBSA and MBSA significantly (p < 0.05) protected against lipid peroxidation, assessed by the formation of thiobarbituric acid reactive substances (TBARS), and protein damage, evaluated by amino acid analysis, for the three systems assayed, and this protection was always higher than that exhibited by BSA, which was used as control. The order of effectiveness was DBSA > MBSA > BSA and was parallel to the Pnl content in the assayed proteins. These results suggest that antioxidative activity of BSA may also be related to its ability to react with lipid oxidation products and to produce modified BSA with antioxidative activity. This mechanism may also be contributing to the antioxidative activity exhibited by many proteins.

Three oxidized lipid/amino acid reaction products (OLAARPs): 1-methyl-4-pentyl-1,4-dihydropyridine-3,5-dicarbaldehyde, 1-(5-amino-1-carboxypentyl)pyrrole, and N-(carbobenzyloxy)-1(3)-[1-(formylmethyl)hexyl]-l-histidine dihydrate, were prepared and tested for antioxidative activity in a microsomal system in order to investigate the effect that OLAARP formation may be playing in the oxidative stress process. The microsomal system consisted of freshly prepared trout muscle microsomes, which were oxidized in the presence of 5 microM Cu2+, 1 mM Fe3+/5 mM ascorbate, or 1 mM Cu2+/10 mM H2O2, and the compound to be tested as antioxidant added at 50 microM. At different periods of time, samples were tested for lipid peroxidation, assessed by the formation of thiobarbituric acid reactive substances (TBARS), and protein damage, which was evaluated by the formation of protein carbonyls and amino acid analysis. The three OLAARPs and butylated hydroxytoluene significantly (p < 0.05) protected against lipid peroxidation and protein damage for the three systems assayed. On the contrary, neither the amino acids used in the preparation of OLAARPs nor alpha-tocopherol, mannitol, aminoguanidine, or 4, 5-dihydroxy-1,3-benzenedisulfonic acid exhibited this constant protection. Because OLAARPs were produced at inhibitory levels during microsomal lipid peroxidation, these results suggest that OLAARP formation may be an antioxidative defense mechanism by which oxidative stress is feed-back-inhibited, delaying the damage caused by reactive oxygen species.