Study On Bioactivity Of Extracellular Polysaccharides From Nostoc Flagelliforme Cells In Liquid Suspension Culture

Nostoc flagelliforme is a kind of terrestrial cyanobacteria and can grow well inarid regions. It has high value in edible and medicinal properties. At present, wildNostoc flageliforme is scare. Nostoc flageliforme in liquid suspension culture canimprove the growth speed and doesn’t consume wild resources, so it is an importantapproach of Nostoc flagelliforme acquisition. Nostoc flageliforme in liquid suspensionculture is abundant in many active components and its polysaccharides are one of theimportant active components. Nostoc flagelliforme polysaccharides are considered as anew type of bioactive polysaccharides and have been taken seriously in antiviral,antitumor and so on. The bioactivities remain to be explored.Therefore, the research subject was Nostoc flagelliforme in liquid suspensionculture, extracellular polysaccharides were extracted and researchedimmunocompetence in vivo and vitro, anti-microbial activity and anti-inflammatoryactivity. The above study can provide theoretical basis for the research anddevelopment of Nostoc flagelliforme polysaccharides in functional food and medicine.The experiments drew the following results:1. Through evaporation, deproteinization, dialysis of Nostoc flagelliforme culturesolution and so on, extracellular polysaccharides from Nostoc flagelliforme wereobtained. By using single factor experiment and response surface optimization, thebest extracting process conditions for Nostoc flagelliforme extracellularpolysaccharides were: alcohol concentration99%, alcohol volume4.5times,concentrate ratio8.2. In order to study immunomodulatory activity of extracellular polysaccharidesisolated from Nostoc flageliforme in vitro, the effects of these polysaccharides onproliferation and transformation activity on mice spleen lymphocytes at differentculture time points (0,12,24,36,48,60, and72h) and under different concentrations (0,25,50,100and200μg/mL) were compared. The results showed that Nostocflagelliforme polysaccharides enhanced proliferation and transformation of micespleen lymphocytes in time-and dose-dependent manner. Therefore, Nostocflageliforme polysaccharides can enhance immunomodulatory effects on mice spleenlymphocytes in vitro.3. Through the tests of mice organ index, carbon particle clearance index, delayedtype hypersensitivity and quantitative hemolysis spectrophotometry, the immuneactivity effects in mice of extracellular polysaccharides isolated from Nostocflageliforme were observed. The results showed that, compared with the model group,the mice in polysaccharides groups organ index, carbon particle clearance index,phagocytic index and paws thickness increased significantly, and antibody secretion ofspleen B cells ability enhanced significantly. The study shows that nostoc flageliformepolysaccharides can enhance mice immunocompetence in vivo.4. By measuring the sizes of inhibition zone diameter around the filter paper, anti-microbial activity of Nostoc flageliforme extracellular polysaccharides was studied.The results showed that, the polysaccharides could inhibit Escherichia coli, Bacillussubtilis, Staphylococcus aureus and especially Salmonella to a certain degree, and theinhibition increased with the increase of polysaccharides concentrations; Thepolysaccharides could inhibit Penicillium and Monascus, while no inhibition toRhizopus.5. Through the observation on effects of Nostoc flageliforme extracellularpolysaccharides on mice inflammation, we concluded that the polysaccharides couldeffectively alleviate the inflammation of mice ears induced by xylene in dose-dependent manner; The polysaccharides had certain inhibition on inflammation ofmice hind paws induced by carrageenin, especially in the low dose the effect was best.