Publications by authors named "Ali Zaiter"

4 Publications

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Elicitation of Antimicrobial Active Compounds by -Fungus Co-Cultures.

Microorganisms 2021 Jan 15;9(1). Epub 2021 Jan 15.

Université de Lorraine, INRAE, DynAMic, F-54000 Nancy, France.

The bacteria of the genus and Basidiomycete fungi harbor many biosynthetic gene clusters (BGCs) that are at the origin of many bioactive molecules with medical or industrial interests. Nevertheless, most BGCs do not express in standard lab growth conditions, preventing the full metabolic potential of these organisms from being exploited. Because it generates biotic cues encountered during natural growth conditions, co-culture is a means to elicit such cryptic compounds. In this study, we explored 72 different -fungus interaction zones (SFIZs) generated during the co-culture of eight and nine fungi. Two SFIZs were selected because they showed an elicitation of anti-bacterial activity compared to mono-cultures. The study of these SFIZs showed that co-culture had a strong impact on the metabolic expression of each partner and enabled the expression of specific compounds. These results show that mimicking the biotic interactions present in this ecological niche is a promising avenue of research to explore the metabolic capacities of and fungi.
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http://dx.doi.org/10.3390/microorganisms9010178DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7830452PMC
January 2021

New approach in the characterization of bioactive compounds isolated from Calycotome spinosa (L.) Link leaves by the use of negative electrospray ionization LITMS, LC-ESI-MS/MS, as well as NMR analysis.

Bioorg Chem 2020 03 23;96:103535. Epub 2019 Dec 23.

Laboratoire de Mycologie, de Biotechnologie et de l'Activité Microbienne (LaMyBAM), Département de Biologie Appliquée, Université des Frères Mentouri, Constantine1, BP, 325 Route de Aïn El Bey, Constantine 25017, Algeria.

Two novel compounds were isolated for the first time from Calycotome spinosa (L.) Link, an alkaloid 5-Hydroxy-1H-indole (4) and a cyclitol D-pinitol (5), together with the three well-known flavonoids; Chrysin-7-O-(β-D-glucopyranoside) (1), Chrysin-7-O-β-D-(6″-acetyl)glycopyranoside (2) and Apigenin-7-O-β-D-glycopyranoside (3). The chemical structures of the isolated compounds were elucidated by spectroscopic data and mass spectrometric analyses; including a fresh approach 1D-NMR, 2D-NMR with LC-ESI-MS/MS. In this study, the new compound (4) that has been obtained from the leaves MeOH extract presented the best radical scavenging activity (DPPH) (IC < 10 µg/mL) compared to the standard butylated hydroxytoluene (BHT, IC = 34.73 ± 0.23 μg/mL) and showed the highest total antioxidant capacity (TAC = 985.54 ± 0.13 mg AAE/g extract) in contrast to ascorbic acid (TAC = 905.95 ± 0.07 mg AAE/g extract). Furthermore, the strongest reducing power (EC = 344.82 ± 0.02 µg/mL), as well as the remarkable scavenging potential by ABTS assay (IC = 7.8 ± 0.43 µg/mL), were exhibited by the same composite (4). Followed by the methanol crude extract and the compound (3) that also showed a potent antioxidant (DPPH; IC = 41.04 ± 0.15 and 47.36 ± 0.21 µg/mL, TAC; 671.02 ± 0.21 and 608.67 ± 0.34 mg AAE/g extract, FRAP; EC = 763.73 ± 0.32 and 814.61 ± 0.31 µg/mL, ABTS; IC = 19.18 ± 0.06 and 63.72 ± 0.64 µg/mL, respectively), but less than the previous samples. On the opposite side, compound (5) had the lowest activity, in which its values were less interesting to determine. Moreover, compound (4) has equally exerted an attractive antibacterial activity against Staphylococcus aureus (ATTC-25923), Pseudomonas aeruginosa (ATTC- 27853) and Salmonella abony (NCTC 6017), as measured by the disc diffusion assay, with inhibition zones of 16 ± 0.5, 9.83 ± 0.29 and 8 ± 0.28 mm, in that order. To the best of our knowledge, 5-Hydroxy-1H-indole was isolated from plants for the second time in our current work. Thus, the obtained results from this investigation propose that the leaves of C. spinosa are a rich natural source for value molecules as potential antioxidants and antimicrobial agents for best human health.
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http://dx.doi.org/10.1016/j.bioorg.2019.103535DOI Listing
March 2020

Optimisation of phytochemical characteristics and antioxidative properties of Foeniculum vulgare Mill. seeds and Ocimum basilicum L. leaves superfine powders using new parting process.

Phytochem Anal 2020 Mar 31;31(2):154-163. Epub 2019 Jul 31.

LCP-A2MC (Laboratoire de Chimie et Physique - Approche Multi-échelles des milieux Complexes), Université de Lorraine, 1, Boulevard Arago, Metz Cedex 03, 57078, France.

Introduction: Fennel (Foeniculum vulgare Mill.) and basil (Ocimum basilicum L.) are two aromatic medicinal plants. Recently, a new parting process which is named CDS "Comminution and to control Diffraction Sieving" is taken into consideration and its positive effect on the extraction of bioactive compounds from the plants, without any solvent, is reported.

Objective: Study the effect of CDS on phytochemical properties of superfine powders of fennel seeds and basil leaves.

Methods: Fennel seeds and basil leaves superfine powders were fractionated as follows: 100-180 μm, 180-315 μm, 315-500 μm, > 500 μm and unsieved superfine powders. Extraction of polyphenols was carried out using hydromethanolic maceration. The essential oils were extracted by maceration with dichloromethane. The antioxidant activities were evaluated by DPPH (2,2-diphenyl-1-picrylhydrazyl) assay. Using liquid chromatography ultraviolet electrospray ionisation mass spectrometry (LC-UV-ESI-MS), concentrations of characterised phenolic compounds were measured. The essential oils compositions were characterised using gas chromatography mass spectrometry (GC-MS).

Results: In fennel seeds, the 100-180 μm fraction had maximum antioxidant activity and LC-UV-ESI-MS analyses proved that the best extraction of certain polyphenols was obtained in the 100-180 μm fraction. In basil leaves, the best antioxidant activity corresponded to the 315-500 μm fraction and LC-UV-ESI-MS analyses showed that the polyphenols were concentrated in the < 315 μm fractions. For both plants, GC-MS presented that the essential oils were concentrated in the 315-500 μm fraction.

Conclusion: CDS as a new green parting process leads to improve the phytochemical properties of these two superfine plant powders in the specific granulometric classes.
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http://dx.doi.org/10.1002/pca.2875DOI Listing
March 2020

Effect of particle size on antioxidant activity and catechin content of green tea powders.

J Food Sci Technol 2016 Apr 18;53(4):2025-32. Epub 2016 Apr 18.

Unité de Recherche - Animal et Fonctionnalités des Produits Animaux, Université de Lorraine, 1 Boulevard Arago, F-57078, Cedex 03 Metz, France.

This work evaluated the effect of grinding and sieving process of green tea leaves on particle size distribution and antioxidant activity. Granulometric classes ranging from 20 μm to 500 μm were studied. Hydroalcoholic extracts of green tea powders (GTPs) were analysed for total phenolic, total flavonoid, and catechin contents. The fraction of 100-180 μm ground at 6000 rpm showed the maximum catechin content with 33.5 mg/g dry matter (DM) and, the best antioxidant activity with IC50 values of 0.28 μg/mL and 0.13 μg/mL using DPPH and ABTS radical scavenging assays, respectively. However, antioxidant properties and catechin content decreased for particle of sizes less than 50 μm. Catechin content was higher for those ground at 6000 rpm as compared to at 18,000 rpm. The best grinding conditions and particle size were 6000 rpm and 100-180 μm.
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http://dx.doi.org/10.1007/s13197-016-2201-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4926930PMC
April 2016
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