RESUMEN
AIM: To study the antioxidant activity of crude polysaccharide(DCPP) and purified polysaccharide DCPP3c-1 from suspension-cultured protocorms of Dendrobium candidum in vitro. METHODS: The scavenging effect of crude and purified polysaccharide on radical was tested by 10-phenantthroline-Fe~(2+)-H_2O_2 systems and ammonium peroxydisulfate/ N,N,N′,N′-tetramethylethanediamine systems.The content of malonaldehyed(MDA) in mice liver homogenate and mice liver mitochondria were measured by TBA assay,and the swelling extent of mice liver mitochondria was also detected by spectrophotometric methods. RESULTS: DCPP and DCPP3c-1 could significantly scavenge ?OH and O~-_2,and the polysaccharide on ?OH showed dose-effect relationship.The 50% inhibitory concentrations(IC_(50)) of DCPP and DCPP3c-1 scavenging ?OH were 0.982 mg/mL and 0.930 mg/mL,and the IC_(50) of DCPP scavenging O~-_2 was 0.619 mg/mL.DCPP3c-1-1 had the highest inhibitory rate on O~-_2 at the concentration of 0.615 mg/mL,and then the inhibitory rate decreased with the increasing of its concentration.DCPP and DCPP3c-1 had inhibitory effects on lipid peroxidation in mice liver homogenate produced by itself and induced by Fe~(2+) or H_2O_2,and especially DCPP had stronger activity than DCPP3c-1.DCPP and DCPP3c-1 could inhibit the production of MDA in mice liver mitochondria,and could also decrease the swelling of mice liver mitochondria induced by ?OH. CONCLUSION: Both DCPP and DCPP3c-1 have antioxidant effects.