Synthesis, characterization, and antibacterial activities of novel starch derivatives against E. coli and S. aureus

• Published in: Starch - Stärke Vol. 74; no. 7-8
• Main Authors: Sosa‐Santillán, Gerardo de Jesús, Zugasti‐Cruz, Alejandro, Enríquez‐Medrano, Francisco Javier, Avérous, Luc, Pollet, Eric, Valdés‐Ramos, Karyme Guadalupe, Gomez, Cesar Gerardo, Romero, Marcelo Ricardo, Garcia‐Lobato, Marco Antonio, Pérez‐Aguilar, Nancy Verónica, Oyervides‐Muñoz, Ernesto
• Format: Journal Article
• Language: English
• Published: Weinheim Wiley Subscription Services, Inc 01-07-2022
• Subjects: Aldehydes; Amino groups; Ammonium; Ammonium salts; antibacterial; Antibacterial activity; biocompatible; E coli; Escherichia coli; Hydroxyl groups; Imines; NMR; Nuclear magnetic resonance; Oxidation; Pyridinium; Salts; sodium periodate; Staphylococcus aureus; Starch; Synthesis
• ISSN: 0038-9056; 1521-379X
• DOI: 10.1002/star.202100142

Three novel starch derivatives with antibacterial properties are synthesized through a rather simple multistep synthesis route. In a first step, sodium periodate oxidation of the hydroxyl groups (C2–C3) of starch yields a di‐aldehyde structure, which is used to attach N,N‐dimethylbenzylamine by Schiff base formation. Then, the amino groups of aminated starch are quaternized with three different ammonium salts (4‐bromobutyl‐pyridinium bromide, 4‐bromobutyl‐benzalkonium bromide, and 4‐bromobutyl‐quinolinium bromide). The different resulting products are fully characterized by FTIR, 1H NMR, and SEC analysis. Their antibacterial properties are evaluated against Escherichia coli and Staphylococcus aureus in vitro to obtain minimum inhibitory and bactericidal concentrations. All the starch derivatives show strong antibacterial activities against Gram‐negative E. coli strain and Gram‐positive S. aureus. Finally, hemolysis assays show that two of the starch derivatives obtained have no significant hemolytic effect on isolated human red cells.
Starch is oxidized using sodium periodate, then it is aminated with N,N‐dimethylbenzylamine. Subsequently, three quaternary ammonium salts having a bromide‐terminated group are synthesized and grafted along the aminated starch chains by a quaternization reaction between the tertiary amine of the aminated starch and the bromide end‐groups of the synthesized salts. Such modifications provide antibacterial properties to the starch derivatives against E. coli and S. aureus strains. Three different quaternary ammonium salts with a bromide‐terminated group are synthesized. Starch is oxidized, aminated, and quaternized with the synthesized salts. All the starch derivatives showed antibacterial properties against E. coli and S. aureus. All the products showed biocompatibility with human blood.