β -Alkylated oligomaltosides as new alternative preservatives: antimicrobial activity, cytotoxicity and preliminary investigation of their mechanism of action

Abstract

The need for developing efficient and safe alternatives to parabens has been growing in the cosmetic and pharmaceutical industries. To this end, the antimicrobial activities and safety of methyl-β-d-maltoside, methyl-β-d-maltotrioside and their dodecyl homologues were investigated. Antimicrobial activities of methyl- and dodecyl-β-d-oligomaltoside have been tested on European pharmacopoeia reference strains. When effective, minimal inhibitory concentrations ranged from 32 to 1024mgl(-1) . Methyl derivatives exhibited greater antibacterial properties, while their dodecyl homologues were more active on fungal strains. To elucidate the mechanism of action of methyl compounds, enzymatic inhibition assays of key maltose metabolism enzymes have been conducted. Methyl-β-maltotrioside (MeG3) was found to be effective in inhibiting microbial glucoamylase and α-amylase. MeG3 and dodecyl-β-maltotrioside cytotoxicity were also checked on HepG2 cells and were found to be low, compared with benzalkonium chloride or parabens. Methyl- and dodecyl-β-maltoside or maltotrioside were found to be active against reference strains used for preservatives efficacy testing. Methyl derivatives could act through an interesting inhibition of the microbial enzymatic metabolism. Given their very simple chemical structure, low toxicity and good antimicrobial activity, methyl-β-d-oligomaltosides could represent a valuable alternative to currently used preservatives such as parabens.