Enhanced antimicrobial activities of polymerized arbutin and its derivatives prepared by oxidative polymerization of arbutin

The amplified antimicrobial activities of poly(arbutin) [poly(arb)] and its 10% octylated derivative [poly(arb)-C810] are described in this paper. Poly(arb) was prepared from monomeric arbutin via oxidative polymerization in an aqueous media, and poly(arb)-C810 was prepared by alkylation of poly(arb) with octyl isocyanate. The minimum inhibitory concentration of arbutin, poly(arb), and poly(arb)-C810 were determined to be 111, 15.2, and 52.6 mg/mL against Escherichia coli and 111, 1.00, and 1.00 mg/mL against StapHylococcus aureus, respectively. The higher antimicrobial activity of polymeric arbutin compared with monomeric arbutin was proposed to be the result of the neighboring effect of phenolic groups of polymers along with the concentration effect of the polymers on the surface of the culture plate, which was proved by ultraviolet–visible spectrophotometry. •For antimicrobial activity against E. coli and S. aureus, polymer effect was observed.•About 100 times higher antimicrobial activity against S. aureus was observed for polyarbutin compared with arbutin.•Polymer effect mechanism on antimicrobial activity was postulated.