Structural characterization and biological properties of degradation byproducts from hyaluronan after acid hydrolysis

► Thermal acid degradation of hyaluronan yields unwanted degradation byproducts (DB). ► The major DB were identified as derivatives of furan and cylopentanone. ► Some of the DB were found to be toxic for cell growth. ► The unwanted DB can be removed from hyaluronan fragments by ultrafiltration.