Degradation of high-molecular-weight hyaluronan by hydrogen peroxide in the presence of cupric ions

Abstract

Dynamic viscosity ( η) of the high-molecular-weight hyaluronan (HA) solution was measured by a Brookfield rotational viscometer equipped with a Teflon cup and spindle of coaxial cylindrical geometry. The decrease of η of the HA solution, indicating degradation of the biopolymer, was induced by a system containing H 2O 2 alone or H 2O 2 plus CuCl 2. The reaction system H 2O 2 plus CuCl 2 as investigated by EPR spin-trapping technique revealed the formation of a four-line EPR signal characteristic of a DMPO–OH spin adduct. Thus, hydroxyl radicals are implicated in degradation of high-molecular-weight HA by the system containing H 2O 2 and CuCl 2.