Surface activities, biodegradability and antimicrobial properties of n‐alkyl glucosides, mannosides and galactosides

Abstract

n‐Alkyl α‐and β‐glucopyranosides, α‐D‐mannopyranosides and β‐D‐galactopyranosides with alkyl chains having from 8 to 12 carbon atoms were synthesized and their surface properties‐such as static surface tension (γ), critical micelle concentration (CMC), occupation area of molecule, dynamic surface tension and foaming properties, biodegradability and antimicrobial activities—were evaluated. Alkyl glycosides containing C8 to C12 carbon chains showed surface activities and critical micelle concentrations. D‐Glucoside, D‐mannoside and D‐galactoside having the same alkyl chain showed similar surface tension lowering at CMC (γCMC) and occupation area of the molecule at the surface. Among the alkyl glucosides, α‐anomers were less hydrophilic than β‐anomers. All alkyl glycosides tested in this study were readily biodegraded by activated sludge of a municipal sewage plant compared to those of ethoxylated nonionic alcohols. The difference of the hydrophilic glycopyranoside group in biodegradability was not seen clearly. n‐Alkyl glycosides containing C8 to C12 alkyl chains showed a broad spectrum of increasing antimicrobial activity. n‐Dodecyl α‐D‐mannopyranoside was the most effective, the order of antimicrobial activity being mannopyranoside > glucopyranoside > galactopyranoside group. Members of this class of compounds exhibit the physicochemical and biological properties needed both for a wide range of applications and for environmental acceptance.