Studies On Extraction, Screening And Immunomodulation Of Polysaccharides From Five Dendrobium In Yunnan

Objective: To extract polysaccharides from five Dendrobium medicinal plants,screening and observe its effects on immune function in mice.Methods: After drying and crushing the stem of five Dendrobium medicinal plants ,the crude polysaccharides were obtained by alkali extraction and alcohol precipitation.The polysaccharides were identified by Molish test. Immunosuppressive mice were administered Dendrobium polysaccharides through stomach. A best Dendrobium polysaccharide should be screened by investigating the recovery rate of peripheral blood WBC number and the weight of immune organs.Toxicity test and a series of immunopharmacological tests(the weight and index of immune organs, engulfing carbon granula test, serum hemolysin test, T, B lymphocyte transformation test of mouse spleen cell, ANAE test , serum complement test) were done to evaluate the effects of this Dendrobium polysaccharide on immunomodulation.Results: The polysaccharide from Dendrobium thyrsiflorum Rchb.f polysaccharide (DTP) . can increase the peripheral blood WBC number and the weight of immune organs greatly. So DTP were choosed to do toxicologic test and a series of immunopharmacological tests. The MTD of toxicologic test is 7. 8g/kg/d.The results of immunopharmacological test show that the spleen index in low and middle dosage treatment was higher than that of control group(P<0.01); the macrophage engulfing carbon granula ability in middle and high dosage treatment are higher than that of control group (P<0.01, P<0.05) ; the OD and HC₅₀ value in middle and high dosage treatment was higher than that of control group (P<0.05); the ConA difference in T,B lymphocyte transformation test has no significant difference between experimented groups and control group (P>0.05); but the LPS difference in middle and high dosage treatment has obvious difference with control group (P<0.05); there is no difference among groups in ANAE test; the content of C3 in middle and high dose group and the content of C4 in high dose group has significant difference with control group (P<0.01).