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Nanoparticles (NPs), offering high specific surface, are considered as the best potential anti-microbial agents for a wide range of medical nanotechnology. Among them, silver NPs (AgNPs) allow high biocidal activity. A design of ecological capsules is proposed where AgNPs of 22 nm in diameter are grafted on the surface of biobased nanocrystals obtained from cellulose (CNC) and chitin (ChiNC). These silver nanohybrids are dispersed in calcium-alginate microgels of 45–50 µm in diameter using microfluidic tools. Such double level of immobilization of AgNPs leads to highly stable carriers, prolongs shelf life and raises bioactivity, with a precise control of well dispersed AgNPs as determined by scanning transmission electron microscopy, UV-Vis spectroscopy and atomic absorption spectroscopy. Preliminary tests for antimicrobial activities of these new microgels have shown a significant inhibitory effect on Candida albicans, the most common fungal pathogen, responsible for thrush and vaginal yeast infections, for very low levels of silver.

Antimicrobial agents are safe preservatives having the ability to protect foods from microbial spoilage and extend their shelf life. Many factors, including antimicrobials’ chemical features, storage environments, delivery methods, and diffusion in foods, can affect their antimicrobial activities. The physical-chemical characteristics of the food itself play an important role in determining the efficacy of antimicrobial agents in foods; however the mechanisms behind it have not been fully explored. This review provides new insights and comprehensive knowledge regarding the impacts of the food matrix, including the food components and food (micro)structures, on the activities of antimicrobial agents. Studies of the last 10 years regarding the influences of the food structure on the effects of antimicrobial agents against the microorganisms’ growth were summarized. The mechanisms underpinning the loss of the antimicrobial agents’ activity in foods are proposed. Finally, some strategies/technologies to improve the protection of antimicrobial agents in specific food categories are discussed.

In this research work, pristine and various concentrations (2.4 wt%) of graphene oxide (GO)/carbon sphere (CS)–doped Al2O3 nanostructures (NSs) were synthesized with the chemical sol–gel method. Aluminum oxide (Al2O3) exhibits quick recombination of electrons and holes with a low specific surface to limit catalytic and antibacterial activities. Al2O3 doped with CS is good in wastewater treatment and reduces the size of NSs. The incorporation of graphene oxide (GO) into Al2O3 at different concentrations (2 and 4 wt%) enhances both the structural and chemical stabilities of the resulting material while concurrently decreasing the number of charge carriers and reducing the band gap energy. This modified Al2O3-GO composite exhibits promising potential for utilization in dye degradation and antibacterial activity. A series of characterizations were performed to investigate the structural, morphological, and optical properties. The NSs exhibited excellent catalytic activity (CA) against rhodamine B (RhB) dye in acidic, basic, and neutral media. The antimicrobial activity was tested against Escherichia coli. Pairs of electrons and holes are the primary building blocks for the production of reactive oxygen species (ROS), which causes bacteria to die. The significant inhibition zones against E. coli were calculated to be approximately 5.65 mm when compared to ciprofloxacin. Moreover, in silico investigations have revealed the possible inhibitory impact of produced nanomaterials (GO/CS-doped Al2O3) on DNA gyrase and FabI enzymes of fatty acid biosynthesis.

Sweet potato (Ipomoea batatas) is one of the most important food crops worldwide and its leaves provide a dietary source of nutrients and various bioactive compounds. These constituents of sweet potato leaves (SPL) vary among varieties and play important roles in treating and preventing various diseases. Recently, more attentions in health-promoting benefits have led to several in vitro and in vivo investigations, as well as the identification and quantification of bioactive compounds in SPL. Among them, many new compounds have been reported as the first identified compounds from SPL with their dominant bioactivities. This review summarizes the current knowledge of the bioactive compositions of SPL and their health benefits. Since SPL serve as a potential source of micronutrients and functional compounds, they can be further developed as a sustainable crop for food and medicinal industries.

This paper reports the synthesis, characterization and antimicrobial evaluation of complexes prepared from different transition metals and Schiff’s base ligand, 3-methoxy-4-hydroxyphenylmethyelene(2-hydroxyphenyl)amine synthesized from vanillin and 2-aminohpenol. The structural features of the resulting complexes and ligands were characterized by elemental analysis, magnetic susceptibility, molar conductance, Fourier Transform-Infra Red, UV-Vis (electronic spectra), and Atomic absorption spectroscopic methods. The FT-IR spectral data indicated the coordination of phenolic oxygen and azomethane nitrogen to the central metal ions. The results of electronic spectral studies and magnetic susceptibility measurements suggested an octahedral geometry for Zn(II), Ni(II), Cr(III), and Fe(III) complexes but square planar for Cu(II) complex. The ligands and their complexes were screened in-vitro for their antibacterial and antifungal activities against bacterial strains, (Escheria coli and Staphylococcus aureus) and fungal strains (Aspergillus niger and Colletotrichum gloeosporioides). The results demonstrated that the free ligand showed higher activities than the corresponding complexes in both bacteria and fungi, and comparable with the standard, suggesting the potential of the ligand for the use of antimicrobial test.

Edible coatings and films (ECF) are employed as matrixes for incorporating antimicrobial nanoparticles (NPs), and then they are applied on the fruits and vegetables to prolong shelf life and enhance storage quality. This paper provides a comprehensive review on the preparation, antimicrobial properties and mechanisms, surface and physical qualities of ECF containing antimicrobial NPs, and its efficient application to vegetables and fruits as well. Following an introduction on the properties of the main edible coating materials, the preparation technologies of ECF with NPs are summarized. The antimicrobial activity of ECF with NPs against the tested microorganism was observed by many researchers. This might be mainly due to the electrostatic interaction between the cationic polymer or free metal ions and the charged cell membrane, the photocatalytic reaction of NPs, the detachment of free metal ion, and partly due to the antimicrobial activity of edible materials. Moreover, their physical, mechanical and releasing properties are discussed in detail, which might be influenced by the concentration of NPs. The preservation potential on the quality of fruits and vegetables indicates that various ECF with NPs might be used as the ideal materials for food application. Following the introduction on these characteristics, an attempt is made to predict future trends in this field.

This paper reports the synthesis, characterization and antimicrobial evaluation of complexes prepared from different transition metals and Schiff’s base ligand, 3-methoxy-4-hydroxyphenylmethyelene(2-hydroxyphenyl)amine synthesized from vanillin and 2-aminohpenol. The structural features of the resulting complexes and ligands were characterized by elemental analysis, magnetic susceptibility, molar conductance, Fourier Transform-Infra Red, UV-Vis (electronic spectra), and Atomic absorption spectroscopic methods. The FT-IR spectral data indicated the coordination of phenolic oxygen and azomethane nitrogen to the central metal ions. The results of electronic spectral studies and magnetic susceptibility measurements suggested an octahedral geometry for Zn(II), Ni(II), Cr(III), and Fe(III) complexes but square planar for Cu(II) complex. The ligands and their complexes were screened in-vitro for their antibacterial and antifungal activities against bacterial strains, (Escheria coli and Staphylococcus aureus) and fungal strains (Aspergillus niger and Colletotrichum gloeosporioides). The results demonstrated that the free ligand showed higher activities than the corresponding complexes in both bacteria and fungi, and comparable with the standard, suggesting the potential of the ligand for the use of antimicrobial test.

This paper reports the synthesis, characterization and antimicrobial evaluation of complexes prepared from different transition metals and Schiff’s base ligand, 3-methoxy-4-hydroxyphenylmethyelene(2-hydroxyphenyl)amine synthesized from vanillin and 2-aminohpenol. The structural features of the resulting complexes and ligands were characterized by elemental analysis, magnetic susceptibility, molar conductance, Fourier Transform-Infra Red, UV-Vis (electronic spectra), and Atomic absorption spectroscopic methods. The FT-IR spectral data indicated the coordination of phenolic oxygen and azomethane nitrogen to the central metal ions. The results of electronic spectral studies and magnetic susceptibility measurements suggested an octahedral geometry for Zn(II), Ni(II), Cr(III), and Fe(III) complexes but square planar for Cu(II) complex. The ligands and their complexes were screened in-vitro for their antibacterial and antifungal activities against bacterial strains, (Escheria coli and Staphylococcus aureus) and fungal strains (Aspergillus niger and Colletotrichum gloeosporioides). The results demonstrated that the free ligand showed higher activities than the corresponding complexes in both bacteria and fungi, and comparable with the standard, suggesting the potential of the ligand for the use of antimicrobial test.

Two novel coppe(tr) complexes (Fig. 1) with 4-(diethylamino)salicylald.hyd. as ligand (HL) and o-diimine - 2,2'-bipyridine (bipy) or 1,lO-phenanthroline (phen) with potentially antimicrobial activity are described. Complex 1 is a mononuclear copper(Il) complex, [Cu(bipy)(L)]BF+.HzO, whereas complex 2 is a binuclear [Cu(phen)(L)]z(BF+)2. Antimicrobial activities of those complexes, coffesponding Cu(II) salt, o,-diimines (phen and bipy) and ligand HL were studied by examining the minimum inhibitory concentration (MIC) on four Gram-positive and four Gram-negative bacterial species and three fungal strains. Amikacin and fluconazole were used as the standard drugs for the comparison of the MIC values. Cu(II) complexes I and 2 demonstrated significantly stronger antibacterial activities than parent ligands (adiimines and HL) or starting Cu(II) salt. Complex 2 is the most active of all examined compounds. The activity of this complex against E. coli is comparable to the activity of the standard antibiotic amikacin. Unlike increasing antibacterial activity of complexes 1 and2 in regard to all coordinated ligands, antifungal activities showed the opposite trend.

A small series of 1-acetyl-2-(4-alkoxy-3-methoxyphenyl)cyclopropanes was prepared, starting from dehydrozingerone (4-(4-hydroxy-3-methoxyphenyl)-3-buten-2-one) and its O-alkyl derivatives. Their microbiological activities toward some strains of bacteria and fungi were tested, as well as their in vitro cytotoxic activity against some cancer cell lines (HeLa, LS174 and A549). All synthesized compounds showed significant antimicrobial activity and expressed cytotoxic activity against tested carcinoma cell lines, but they showed no significant influence on normal cell line (MRC5). Butyl derivative is the most active on HeLa cells (IC50 = 8.63 m), while benzyl one is active against LS174 and A549 cell lines (IC50 = 10.17 and 12.15 m, respectively).

A small series of 1-acetyl-2-(4-alkoxy-3-methoxyphenyl)cyclopropanes was prepared, starting from dehydrozingerone (4-(4-hydroxy-3-methoxyphenyl)-3-buten-2-one) and its O-alkyl derivatives. Their microbiological activities toward some strains of bacteria and fungi were tested, as well as their in vitro cytotoxic activity against some cancer cell lines (HeLa, LS174 and A549). All synthesized compounds showed significant antimicrobial activity and expressed cytotoxic activity against tested carcinoma cell lines, but they showed no significant influence on normal cell line (MRC5). Butyl derivative is the most active on HeLa cells (IC50 = 8.63 m), while benzyl one is active against LS174 and A549 cell lines (IC50 = 10.17 and 12.15 m, respectively).

Phytochemical screening (saponins, tannins, steroids, alkaloids, flavonoids, phenols and glycosides) of four medicinal plant seeds (Jatropha curcas, Simmondsia chinensis (Jojoba), Moringa oleifera and Datura metel) extracted by aqueous, ethanol and Folch solvents, were examined for their antimicrobial activity against three types of plant pathogenic fungi namely; Botrytis cinerea, Fusarium oxysporum and Rhizoctonia solani, in addition to four types of bacteria, namely; Bacillus cereus, Staphylococcus aureus, Ralstonia solanacearum and Pesudomonas aeruginosa using disc diffusion paper. Results revealed that different concentrations of aqueous extracts were more effective against bacterial activity compared to fungal activity, except for D. metel aqueous extract which showed no antifungal effect and very weak effect on only two of the tested bacteria. B. cereus was more sensitive to J. curcas aqueous extract, while P. aeruginosa was more sensitive to S. chinensis and M. oleifera aqueous extracts. On the other hand, results showed that J. curcas and M. oleifera ethanol extracts were more effective on Staph. aureus growth, while S. chinensis and D. metel did not have any effect on any of the fungi or bacteria under study. The evaluation of the antifungal and antibacterial effect did not confirm the broad spectrum of S. chinensis Folch extract, while M. oleifera and D. metel were more effective on reducing R. solani growth. Also F. oxysporum was affected by J. curcas Folch extract only at high concentrations. These findings support that the traditional use of the plant extracts in the treatment of different infections caused by pathogenic microbes is valuable and should be taken in consideration.

A new Mannich base, N-(1-Morpholinosalicylyl)benzohydrazide (MSB), formed by the condensation of morpholine, benzohydrazide and salicylaldehyde and its Co(II), Ni(II) Cu(II) and Zn(II) complexes have been synthesised. Their structures have been elucidated on the basis of analytical, magnetic, electrical conductivity and spectral methods. On the basis of colour,magnetic moments and spectral data, the geometries of Co(II), Ni(II), Cu(II) and Zn(II) complexes have been assigned. The electrochemical property of the ligand and its complexes in acetonitrile solution was studied by cyclic voltammetry. The X-band ESR spectra of the Cu(II) complex in DMSO at 300 and 77 K were recorded and their salient features are reported. Antibacterial activities of the ligand and its complexes were tested against some selected bacteria. The ligand and all the complexes showed antimicrobial activities.

A new Mannich base, N-(1-Morpholinosalicylyl)benzohydrazide (MSB), formed by the condensation of morpholine, benzohydrazide and salicylaldehyde and its Co(II), Ni(II) Cu(II) and Zn(II) complexes have been synthesised. Their structures have been elucidated on the basis of analytical, magnetic, electrical conductivity and spectral methods. On the basis of colour,magnetic moments and spectral data, the geometries of Co(II), Ni(II), Cu(II) and Zn(II) complexes have been assigned. The electrochemical property of the ligand and its complexes in acetonitrile solution was studied by cyclic voltammetry. The X-band ESR spectra of the Cu(II) complex in DMSO at 300 and 77 K were recorded and their salient features are reported. Antibacterial activities of the ligand and its complexes were tested against some selected bacteria. The ligand and all the complexes showed antimicrobial activities.