Study on the synthesis, structural characterization, and anti-hepatoma cell proliferation effects of sulfated alfalfa polysaccharides

A water-soluble polysaccharide (APS) from <i>Medicago Sativa</i> L. (alfalfa) stems was sulfated via the chlorosulfonic acid (CSA)-pyridine (Pyr) method under three conditions, yielding SAPS-1, SAPS-2, and SAPS-3. Structural characterization (HPGPC, NMR, FT-IR, SEM) confirmed successful sulfation and increased water solubility. SAPSs 1-3 exhibited superior scavenging of DPPH, ABTS, and OH radicals compared to APS. Both APS and SAPSs 1-3 inhibited hepatoma cell (HepG2, Hep3B) proliferation <i>in vitro</i>. Cell cycle analysis showed APS-induced G0/G1 arrest, while SAPS-3 exhibited biphasic regulation by maintaining G0/G1 arrest and stimulating S-phase accumulation. The CSA-Pyr technique enhanced the inhibitory effects, offering promise for developing bioactive compounds from alfalfa biomass.