A new purified sulfated polysaccharide STLH-3 was obtained successfully.
Antioxidant activities of STLH-3 were significantly enhanced.
The effects of scavenging DPPH and •O2− radicals of STLH-3 have exceeded that of Vc.
Sulfation endowed TLH-3 to possess cytotoxicity against HeLa and MCF-7.
STLH-3 had no toxicity on normal cells HELF.