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To prevent foodborne diseases and extend shelf life, antimicrobial agents may be used in food to inhibit the growth of undesired microorganisms. The present study was aimed to determine the antimicrobial and antifungal activities of the fermented medicinal plants extract using Lactobacillus acidophilus ATCC 4356. The fermentation kinetic parameters, biochemical composition and the volatile compounds of the fermented plant extract were assessed. The results showed that, the fermented plants extract exhibited high content in polyphenols, flavonoids, and tannins (152.7 mg AGE/L; 93.6 mg RE/L; and 62.1 mg CE/L, respectively) comparing to non-fermented the extract. The GC-MS headspace analyses showed the presence of 24 interesting volatile compounds. The richness of the fermented plants extracts in polyphenols and bioactive compound, such as Eucalyptol, Camphene, α-Phellandrene, α-Terpinene, improves their biological activity. In addition, the fermented plants extract exhibited a high antimicrobial potential against pathogenic bacteria and fungi determined by different methods. The maximum inhibition showed in the fermented plants extract against Escherichia coli 25922/3, Pseudomonas aeruginosa 27853 ATCC, Staphylococcus aureus 29213 ATCC, Enterococcus aerogenes 13048 ATCC, Phytophthora infestans P3 4/91 R + , P. infestans P4 20/01 R, P. infestans (GL-1). The obtained results support the hypothesis of using lactic fermentation as a functional ingredient to improve food preservation. The bioprocesses of fermentation technology enhance antimicrobial and antifungal activities which could be used in different industrial applications., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Mounting evidence indicates soluble Aβ 42 oligomers as the most toxic species causing neuronal death which leads to the onset and progression of Alzheimer disease (AD). Recently, it has been found that neurotoxic Aβ 42 oligomers grow from monomeric species or arise following secondary nucleation by preformed mature fibrils. Thus, the use of natural compounds such as polyphenols to hinder the growth or to remodel Aβ 42 fibrils is one of the most promising strategies for AD treatment. In our previous study, we showed that 1, 2, 4-trihydroxynaphthalene-2-O-β-d-glucopyranoside (THNG) inhibits Aβ 42 aggregation during the early steps of the aggregation process, inhibits its conformational change to a β-sheet-rich structure, decreases its polymerization, inhibits its fibrillogenisis and reduces oxidative stress and aggregate cytotoxicity. Here, we used different spectroscopic and cell culture methods to check the effect of THNG on fibrils disaggregation. We showed that THNG binds to mature Aβ 42 fibrils, rearrange their secondary structure, and remodels them into non-amyloid, less toxic, species by inhibiting their interaction with the plasma membrane. Our findings reveal that THNG is a good agent to remodel amyloid fibrils and could be used as a starting molecular scaffold to design new anti-AD drugs., (Copyright © 2018 Elsevier B.V. All rights reserved.)

In the present study, we have investigated the effects of polyphenol-rich infusions from carob leaves and OFI-cladodes on inflammation associated with obesity and dextran sulfate sodium (DSS)-induced ulcerative colitis in Swiss mice. In vitro studies revealed that aqueous extracts of carob leaves and OFI-cladodes exhibited anti-inflammatory properties marked by the inhibition of IL-6, TNF-α and nitric oxide (NO) production in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells concomitant with NF-κβ nucleus translocation inhibition. For in vivo investigations, Swiss male mice were subjected to control or high fat diet (HFD). At the 8th week after the start of study, animals received or not 1% infusion of either carob leaves or OFI-cladode for 4 weeks and were subjected to 2% DSS administration in drinking water over last 7 days. After sacrifice, pro-inflammatory cytokines levels in plasma and their mRNA expression in different organs were determined. Results showed that carob leaf and OFI-cladode infusions reduced inflammation severity associated with HFD-induced obesity and DSS-induced acute colitis indicated by decrease in pro-inflammatory cytokines expression (as such TNF-α, IL1b and IL-6) in colon, adipose tissue and spleen. In addition, plasma levels of IL-6 and TNF-α were also curtailed in response to infusions treatment. Thus, carob leaf and OFI-cladode infusions prevented intestinal permeability through the restoration of tight junction proteins (Zo1, occludins) and immune homeostasis. Hence, the anti-inflammatory effect of carob leaves and OFI-cladodes could be attributed to their polyphenols which might alleviate inflammation severity associated with obesity and colitis., (Copyright © 2017 Elsevier Masson SAS. All rights reserved.)

The antioxidant and antibacterial activities of phenolic compounds from cultivated and wild Tunisian Ruta chalepensis L. leaves, stems, and flowers were assessed. The leaves and the flowers exhibited high but similar total polyphenol, flavonoid, and tannin content. Moreover, two organs showed strong, although not significantly different, total antioxidant activity, 2,2-diphenyl-1-picrylhydrazyl scavenging ability, and reducing power. Investigation of the phenolic composition showed that vanillic acid and coumarin were the major compounds in the two organs, with higher percentages in the cultivated organs than in the spontaneous organs. Furthermore, R. chalepensis extracts showed marked antibacterial properties against human pathogen strains, and the activity was organ- and origin-dependent. Spontaneous stems had the strongest activity against Pseudomonas aeruginosa. From these results, it was concluded that domestication of Ruta did not significantly affect its chemical composition and consequently the possibility of using R. chalpensis organs as a potential source of natural antioxidants and as an antimicrobial agent in the food industry., (Copyright © 2016. Published by Elsevier B.V.)

The effects of two extraction methods, used at three ripening stages on the total polyphenol contents and the antioxidant activities of Cumin (Cuminum cyminum L.) seed extracts were studied. The ripening stage effect on some physical properties of cumin seed was significant. The increase of dry matter (from 10.3 to 87.5%) during ripeness was correlated negatively with that of moisture content (from 89.7 to 12.5%). Besides results showed that the full ripe seeds were richer on polyphenols and condensed tannin than unripe ones, and consequently exhibited higher antioxidant activities. However, the unripe seeds had a higher total flavonoid content compared to those of half ripe and full ripe ones. The comparison of two extraction methods showed that soxhlet extracts contained the greatest amount of polyphenols and flavonoids, while maceration samples exhibited higher antiradical and bleaching power assay. Total phenolic contents and IC50 (concentration required to cause a 50% DPPH inhibition) values in cumin seed during their maturation allowed to conclude that antioxidant activity does not depend only on the high content of total phenolics but also on the phenolic composition. A total of 19 phenolic compounds were successfully identified by HPLC analysis during the ripening of cumin seeds. Rosmarinic acid was the major phenolic acid for the unripe seeds. Furthermore, half ripe and full ripe seeds were dominated by p-coumaric acid. These compounds might be considered as interesting bioactive natural substances that may be used in several fields, such as nutraceuticals, cosmetics and agro-food industry.

Background: Juices from four Citrus species of Tunisia were investigated mainly for quality parameters and antioxidant capacity., Results: Citrus reticulata (mandarin) juice had the highest content of total flavonoids (85.33 mg CE L(-1)). The latter also occurred in high quantity (82.01 mg CE L(-1)) in Citrus lemon (lemon) juice which was also marked by its richness in total aroma (70.16 µg mL(-1)) and in total fatty acids (48.10 µg mL(-1)). Mandarin and lemon juices had the highest antioxidant activity, as determined b the β-carotene bleaching assay (26.67% and 22.67%, respectively). Citrus aurantium (bitter orange) juice was characterised by the highest content of total polyphenols (784.67 mg GAE L(-1)) and by the greatest inhibition of DPPH (96.10%). Citrus sinensis (blood orange) juice was only marked by the high quantity of ascorbic acid (36.90 mg mL(-1)). GC/MS analysis of juice aroma showed the predominance of limonene (48.85-69.59%) in mandarin and in bitter and blood oranges, but of camphene (89.05%) in lemon. GC analysis of juice fatty acids revealed their richness in oleic acid (23.13-39.52%). HPLC analysis of juice phenolics indicated the predominance of phenolic acids (73.13-86.40%)., Conclusion: The Citrus species used in this study were considered valuable varieties from the point of view of antioxidant capacity and nutrition., (Copyright © 2010 Society of Chemical Industry.)