Synthesis and Reactivity of 6-Iodo-4H-3,1-Benzoxazin-4-one Towards Nitrogen Nucleophiles and Their Antimicrobial Activities

In attempt to find new pharmacological active molecules, we synthesized 6-iodo-4H-3,1-benzoxazin-4-one and allowed it to react with some nitrogen nucleophiles namely; hydroxylamine hydrochloride, hydrazine hydrate, fomamide, aliphatic amine, aromatic amines, aralkyl amine, different amino acids, heteryl amines, ethanolamine and sodium azide to afford annelated quinazolinone derivatives and other related systems. The synthesized compounds were characterized with the help of spectroscopic techniques including IR, 1H-NMR and Mass spectra. Also their antimicrobial activities were screened against different strains of bacteria and fungi. Keywords: 6-Iodo-4H-3,1-benzoxazin-4-one; quinazolinone derivatives;  nitrogen nucleophiles; antimicrobial activity

Synthesis, surface properties and biological activity of N,N,N-tris(hydroxymethyl)-2-oxo-2-(2-(2-(alkanoyloxy) ethoxy)ethoxy) ethanaminium chloride surfactants

A new series of some cationic surfactants were synthesized namely: 2-(2-(2-(dodecanoyloxy)ethoxy)ethoxy)-N,N,N-tris(hydroxymethyl)-2-oxoethanaminium (DDAC); N,N,N-tris(hydroxymethyl)-2-oxo-2-(2-(2-(tetradecanoyloxy) ethoxy)ethoxy) ethanaminium (TDAC) and N,N,N-tris(hydroxymethyl)-2-oxo-2-(2-(2-(hexadecanoyloxy)ethoxy)ethoxy)ethanaminium (HDAC). The chemical structures of the synthesized cationic surfactants were confirmed using FT-IR and 1H-NMR spectroscopies. The surface tension of the synthesized cationic surfactants was measured at 25, 40 and 55 °C. The surface parameters were determined from the surface tension measurements. The emulsification power and foaming power measurements showed the applicability of these surfactants in the oil field. The biological activity of the synthesized surfactants was measured against pathogenic bacteria (Staphylococcus aureus and Escherichia coli) and fungi (Candida albicans and Aspergllus niger) using inhibition zone diameters. The obtained data revealed that the dodecanoate derivative (DDAC) has more antimicrobial activity against the investigated microorganisms than tetradecanoate and hexadecanoate derivatives (TDAC and HDAC)

Cationic vesicles based on biocompatible diacyl glycerol-arginine surfactants: Physicochemical properties, antimicrobial activity, encapsulation efficiency and drug release

Physicochemical characteristics of cationic vesicular systems prepared from biocompatible diacyl glycerol-arginine surfactants are investigated. These systems form stable cationic vesicles by themselves and the average diameter of the vesicles decreases as the alkyl chain length of the surfactant increases. The addition of DPPC also modifies the physicochemical properties of these vesicles. Among the drugs these cationic formulations can encapsulate, we have considered Ciprofloxacin and 5-Fluorouracil (5-FU). We show that the percentage of encapsulated drug depends on both the physicochemical properties of the carrier and the type of drug. The capacity of these systems to carry different molecules was evaluated performing in vitro drug release studies. Finally, the antimicrobial activity of empty and Ciprofloxacin-loaded vesicles against Gram-positive and Gram-negative bacteria has been determined. Three bacteria were tested: Escherichia coli, Staphylococcus aureus and Klebsiella pneumoniae. The in vitro drug release from all formulations was effectively delayed. Empty cationic vesicles showed antimicrobial activity and Ciprofloxacin-loaded vesicles showed similar or higher antimicrobial activity than the free drug solution. These results suggest that our formulations represent a great innovation in the pharmaceutical field, due to their dual pharmacological function: one related to the nature of the vehiculated drug and the other related to the innate antibacterial properties of the surfactant-based carriers. © 2014 Elsevier B.V.The authors would like to thank the financial support from Spanish Plan National I+D+I MAT2012-38047-C02-02, AGAUR 2009 SRG 246, CTQ2010-14897. Moreover, the project has been co-funded with support from the Commission European Social Fund and Region of Calabria (Italy) and the contract Estancia de Jóvenes Doctores Extranjeros en España, MEC, SB2010-0129.Peer reviewe

Role of aggregate size in the hemolytic and antimicrobial activity of colloidal solutions based on single and gemini surfactants from arginine

Cationic colloidal systems composed of arginine based surfactants (single or gemini structures) and membrane additive compounds such as DLPC or cholesterol have been characterized by means of size distribution and zeta-potential measurements. The single or monocatenary surfactant (LAM) as well as the gemini with the shortest spacer chain (C6(LA)2) formed micelles, while aqueous solutions of pure gemini surfactants with longer spacers (C9(LA)2 and C12(LA)2) formed very big aggregates. The addition of phospholipids or cholesterol changed drastically the aggregation behaviour. In the case of LAM and C 6(LA)2, the incorporation of additives gave rise to the formation of cationic vesicles. For C9(LA)2 and C 12(LA)2, this type of additives promoted the formation of smaller aggregates. All the formulations had positive zeta-potential values and in general exhibited high colloidal stability. We also evaluated the hemolysis and the antimicrobial activity of these systems. The capability of disrupting erythrocyte membranes depends on the hydrophobicity of the molecules and the size of aggregates in the solution. Gemini surfactants with short spacer chains are more hemolytic than their single chain homologue, while gemini surfactants with long spacers are much less hemolytic than their single chain counterpart. Moreover, for the same formulation, the hemolysis depends on the initial concentration of the stock solution used to set up the hemolysis/concentration curve. Results show that small aggregates interact easily with these biological membranes. The alkyl spacer chain and the presence of additives also play an important role in the antimicrobial activity, and, in general, the interaction with bacteria and erythrocytes is affected by the same parameters. The physico-chemical and biological characterization of these systems might be important for several biotechnological applications in which cationic vesicular systems are involved. © The Royal Society of Chemistry 2013.The authors would like to thank the financial support from Spanish Plan National I+D+I CTQ2009-14151-C02-01, CTQ2009-14151-C02-02, AGAUR 2009 SRG 246, CTQ2010-14897, CTQ2010-21183C02-01 and Unidad Asociada “Interacción de tensioactivos con membranes celulares”. Moreover, the project has been co-funded with support from the Commission European Social Fund and Region of Calabria (Italy) and the contract Estancia de Jóvenes Doctores Extranjeros en España, MEC, SB2010-0129.Peer reviewe