Cytotoxic and antioxidant effects of unsaturated hyaluronic acid oligomers

Hyaluronate lyase cleaves hyaluronan chains at a β-d-GalNAc-(1→4)-β-d-GlcA bond, ultimately breaking the polysaccharide down to 3-(4-deoxy-β-d-gluc-4-enuronosyl)-N-acetyl-d-glucosamine. In the present paper, the recombinant hyaluronate lyase (EC 4.2.2.1, HA lyase) of Streptococcus pyogenes bacteriophage H4489A was produced, purified and applied to digest hyaluronan producing unsaturated hyaluronan oligomers. The resulted unsaturated hyaluronan oligomers were purified and subjected to anion-exchange high performance chromatography. The cytotoxic activities of naturally hyaluronan, hyaluronate lyase and unsaturated hyaluronan oligomers were tested and evaluated against HEp-2 (human laryngeal carcinoma), Daoy (human medulloblastoma), MCF-7 (human breast adenocarcinoma), and WiDr (human colon adenocarcinoma) tumor cell lines. Also, their antioxidant activities have been examined by the inhibition of lipid oxidation and free radical scavenging assays.