Study On Separation And Purification Of Polysaccharides From Scutellaria Barbata And Their Pharmacological Activities

Scutellaria barbata D.DON, a herb belonging to the Lamiaceae family, has main active components such as flavones and diterpenoids. Several studies have indicated that extracts of Scutellaria barbata have anti-tumor, anti-virus, anti-oxygen, guard liver, relieve fever, diuresis activities and so on. People often use Scutellaria barbata to therapy a number of human cancers, type B hepatitis and venomous snake bite. There were many reports about Scutellaria barbata, but they focused mainly on flavones, and only a few about Scutellaria barbata polysaccharides. Polysaccharide is a kind of important active components, and has been a hot spot of naturally occurring drugs research. In this paper, the extraction, separation, purification of Scutellaria barbata (Jiangsu) polysaccharides and their physiological activities were studied. The main contents and conclusions are as follows:(1) To optimize the extraction process of Scutellaria barbata polysaccharides with water. On the basis of single factors tests, the four factors including temperature, time, solid-liquid ratio and the extraction times on the yield of the polysaccharides were studied by orthogonal experimental design. Considering the extraction efficiency and quality of polysaccharides, the optimum extraction process was as follows: soaking Scutellaria barbata with water at 90℃for 3 times (3 hours per time) and adding 12 times water. The yield and content of polysaccharide were 2.90% and 30.42%.(2) To study the separation and purification technology of the Scutellaria barbata polysaccharides. After the deproteinization, de-colourisation, dialysis and DEAE-52 column chromatography, four polysaccharides fractions were got: SBP-11, SBP-12, SBP-13 and SBP-14. The purify of SBP-11 is 90.24%, SBP-12 is 88.56%, SBP-13 is 86.42% and SBP-14 is 85.23%. The molecular weight of SBP-11, SBP-12, SBP-13 and SBP-14 determined by HPLC were about 18000 Dal, 65000 Dal, 639000 Dal and 1007000 Dal. GC showed that SBP-11 was composed of rhamnose, fucose, arabinose, glucose and galactose in molar radio of 1:0.21:0.38:0.52:0.78. SBP-12 was composed of rhamnose, arabinose, glucose and galactose in molar radio of 0.71: 0.81:1:0.91. SBP-13 was composed of unknown component, rhamnose, fucose, glucose and galactose in molar radio of 0.14:0.31:0.28:0.21:1. SBP-14 was composed of rhamnose, fucose, glucose and galactose in molar radio of 1:0.15:0.24:0.96.(3) To study the immunological activities of deproteinization polysaccharides(SBP-l) and crude polysaccharides(SBP-2) from Scutellaria barbata. The results were as follows: in the dose of 100mg/kg or 300mg/kg, the effects of SBP-1 towards normal rats on the function of macrophage cell in abdominal cavity were not observed. In the dose of 300mg/kg, SBP-1 significantly enhance the content of haemolysin in mice body (p<0.01) . In the dose of 100mg/kg and 300mg/kg, SBP-1 significantly increases spleen index in immunosuppression mice (P<0.05 or p<0.01) . In the dose of 300mg/kg, SBP-2 significantly enhance the content of haemolysin in mice body (p<0.01) . In the dose of 100mg/kg and 300mg/kg, SBP-2 significantly increases spleen index in immunosuppression mice ((P<0.05 or p<0.001) . Scutellaria barbata polysaccharides can accelerate the recovery of immune function of immunodepression mice.(4) To study the anti-tumor activity in vitro of Scutellaria barbata polysaccharides by using the MTT method. The results were as follows: both SBP-1 and SBP-12 have definite inhihitory action on the gastric cancer cells of AGS, SBP-12 had the better depression effect than SBP-1. Both SBP-1 and SBP-12 have definite inhihitory action on the gastric cancer cells of SGC, the inhihitory action was the best in the middle dose of 160μg/mL. The inhihitory action is weaken when SBP-1 was purified. Both SBP-1 and SBP-12 can inhibit leukemia cells of U937 in the low dose, but advance it's growth in the high dose, the activity cut down when SBP-1 was purified.(5) To study the antioxidant activity of Scutellaria barbata polysaccharides by using the salicylic acid method. The conclusion was: all of them had good ability to scavenge hydroxyl radicals, and the scavenging ability related with the concentrations. The scavenge effect of SBP-11, SBP-12, SBP-13 and SBP-14 were better than that of SBP-1; the scavenge effect of SBP-11 was the best. IC₅₀ of SBP-1 is 2.94mg/mL. IC₅₀ of SBP-11, SBP-12, SBP-13 and SBP-14 is 0.16mg/mL, 0.41mg/mL, 0.35mg/mL and 0.64 mg/mL.