Adel Z. El-Sonbati

Bio: Adel Z. El-Sonbati is an academic researcher from Damietta University. The author has contributed to research in topics: Ligand & Denticity. The author has an hindex of 36, co-authored 236 publications receiving 4666 citations. Previous affiliations of Adel Z. El-Sonbati include Sana'a University & King Khalid University.

Influence of substituent effects on spectroscopic properties and antimicrobial activity of 5-(4'-substituted phenylazo)-2-thioxothiazolidinone derivatives.

Abstract: 5-(4′-substituted phenylazo)-2-thioxothiazolidinone derivatives (HLn) have been synthesized and characterized by elemental analysis, spectra (IR, electronic and 1H NMR). The IR spectral data indicate that the compounds can exist in two resonance structures. The synthesized ligands were screened for their antimicrobial activity against four bacterial species, two Gram positive bacteria (Bacillus cereus and Staphylococcus aureus) and two Gram negative bacteria (Escherichia coli and Klebsiella pneumoniae) as well as against some species various of fungi; Aspergillus niger, Penicillium chrysogenum, Penicillium italicum and Fusarium oxysporium. The results showed that most these ligands are good antibacterial agents against B. cereus and S. aureus and antifungal agents against A. niger and F. oxysporium. HL3 was found to be the most effect compound against all tested microorganisms. The size of clear zone were ordered as follows p-(OCH3 < CH3 < H < Cl < NO2) as expected from Hammett’s constant σR.

Stability of chitosan-a challenge for pharmaceutical and biomedical applications.

Abstract: Chitosan—one of the natural multifunctional polymers—due to its unique and versatile biological properties is regarded as a useful compound in medical and pharmaceutical technology. Recently, considerable research effort has been made in order to develop safe and efficient chitosan products. However, the problem of poor stability of chitosan-based systems restricts its practical applicability; thus, it has become a great challenge to establish sufficient shelf-life for chitosan formulations. Improved stability can be assessed by controlling the environmental factors, manipulating processing conditions (e.g., temperature), introducing a proper stabilizing compound, developing chitosan blends with another polymer, or modifying the chitosan structure using chemical or ionic agents. This review covers the influence of internal, environmental, and processing factors on the long-term stability of chitosan products. The aim of this paper is also to highlight the latest developments which enable the physicochemical properties of chitosan-based applications to be preserved upon storage.

Structural and physical correlations in the biological properties of transition metal heterocyclic thiosemicarbazone and S -alkyldithiocarbazate complexes

Abstract: The nature of metal complexes of heterocyclic thiosemicarbazones reported in the literature through 1989 have been reviewed with an emphasis on variations in stoichiometry and stereochemistry. A brief introduction is followed by a survey of the biological activity of the uncomplexed thiosemicarbazones. Next is a section on the chemical nature of thiosemicarbazones including a discussion of preparative methods, modes of coordination and isomerism. This is followed by a discussion of structural information and biological activity of the iron(III), iron(II), copper(II), cobalt(III), cobalt(II) and nickel(II) complexes of heterocyclic thiosemicarbazones. Short sections on the biological activity of other chelating thiosemicarbazones and metal complexes are also included.