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.