A Study On Extraction, Purification And Antioxidant Activity Of The Polysaccharide Isolated From Lagopsis Supina

Lagopsis supine belongs to the labiatae lagopsis plant,Its other names are small herba leonuri, white herba leonuri and white selfheal. It widely grows in the North china,southwest, northwest, northeast. Bencao Gangmu says that it has the functions of promoting blood circulation to stasis and regulating menstruation and can be used for the treatment of Irregular Menstruation, Hemiplegia, Anemic dizziness and so on. Modern pharmacolcolo gical studies show that the alcohol extraction from Lagopsis supine has the significant functions of promoting blood circulation to stasis and Antioxidation.Polysaceharide, a kind of natural polymers in the tissue of plant, animal and microbe, is one of basic materials to maintain normal operation of the lives, and has many physiological functions such as antioxidation, antidecrepitude, immune regulation and so on. It has no poisonous effect on the body, so it has been applied to clinical service and sold in health product market. Lagopsis supine polysaccharide is one of main active provid ingredients, A deep rescarch on Lagopsis supine polysaccharide is theoretically necessary for the further exploiation of Lagopsis supine. At present, there is no reported report of the study on Lagopsis supine. In the present paper, Lagopsis supine from Zhangjiakou is used asexperimental materials.A systematic research is made concerning the process of extraecion, isolation, purification, and biological activity of the polysaccharide from Lagopsis supine, In this thesis,some advanced separation methods and technologies are explored to effectively isolate and purify the medicinal components from Lagopsis supine.This study has an important academic value in developing modernization of traditional Chinese medicine and promoting comprehendsive utilization of natual plants.Firstly, two different methods of reflux extraction and ultrasonic extraction are respectively adopted to extract polysaccharide from Lagopsis supine. The yields of both the reflux extraction and the ultrasonic extraction are compared.The yields are in turn2.36%and0.18%.Then the optimal reflux extraction conditions are determined by singlefactor method and orthogonal method. The results are as follows:temperature100℃, time2.5h, solid-liquid ratio1:20, extracted twice, and the rate of extracting is2.32%.Six kinds of resin:AB-8, D-101, DM-301, AES-7, ADS-7and AER are evaluated, with decoloration rate, protein removal rate, total sugar retention rate and compositive weighted score as index. ADS-7resin can be used as a high effective one to romove pigment and protein of Lagopsis supine polysaccharide. The decoloration rate is94.6%, the protein removal rate is91.2%, total sugar retention rate is64.3%. The results show that the optimal conditions of romoving pigment and protein are temperature45℃, time1.5h, solid-liquid ratio1:40.Two fractions of LSP1and LSP2are obtained after being fractionated through DEAE-52cellulose and Sephadex G-150column. The relative molecular weights of LSP1and LSP2are111905Da and2540364Da by the determination of high performance gel Permeation chromatography (HPGPC).Antioxidative capability of polysaccharide is determined by salicylic-Fe-H2O2system,1,1-Diphenyl-2-picrylhydrazyl radical2,2-Diphenyl-1-(2,4,6-trinitrophenyl)hydrazyl(DPPH) system, and means of pyrogallol oxidation.The results of antioxidative experiments reveal that Lagopsis supine polysaccharide has some functions of scavenging free radicals on DPPH·,·OH and·O2-. All of their scavenging capability less than Vc.The sequence of scavenging capability to hydroxyl radical is LSP2> LSP1,Clearance ratios of LSP2and LSP1are72.2%and30.5%, at300mg·L-1of solution concentration. The scavenging capability to-DPPH is LSP]>LSP2. the scavenging rate all less than50%with the concentration increased ftom0.2mg·L-1to300mg·L-1. Clearance ratio of LSP1on·O2-is35.8%at200mg·L-1. The scavenging capability of LSP2to·O2-is not obvious, Instead, The rate of pyrogallor autoxidation has an ascending tread with the increasing of polysaccharide concentration.