Study Of The Fermentation Condition Optimization Of Cordyceps Minlitaris,coriolus Versicolor And The Hypoglycemic Effect Of The Compound Made By Their Polysaccharide

With the increasing pressure of people's lives, living standards, the incidence of typeâ…¡diabetes, is continuously growing. The study of traditional chinese drug on the treatment of typeâ…¡diabetes has been a long time. Insulin resistance is one of the principal cause of typeâ…¡diabetes. People are exploring effective ways to lower blood sugar, reduce the incidence of diabetic complications and reduce patient's suffering.In this study, we use Cordyceps Minlitaris L.Lik and Coriolus versicolor(L.ex Fr.) as the research object, first to optimize the medium and the culture conditions of the two mycelium. Then use the extraction rate of polysaccharides as index, optimize the extraction conditions of polysaccharides on the found of single factor experiments by the response surface analysis methodology. Finally, we discuss the hypoglycemic activity of compound recipe between Cordyceps Minlitaris L.Lik and Coriolus versicolor ( L.ex Fr. )'s polysaccharide after the inducement of typeâ…¡diabetes by STZ.The optimization of the fermentation medium and the culture conditions of mycelium of Cordyceps Minlitaris L.Lik were as follows: the best carbon source was sucrose, the optimum nitrogen sources was peptone, the best inorganic salts were MgCl₂ at 0.3 g/L, CaCl2 at 0.1 g/L. After the optimization of the fermentation conditions, the results showed that: the best initial pH 6, speed at 150 r/min, culture temperature at 28℃, incubation time 3 d, inoculation of 6%. For the optimization of the Coriolus versicolor(L.ex Fr.): the best carbon source was malt wort, the best nitrogen source was yeast extract, the optimal type of salt was MgCl at 0.3 g/L. After the optimization of the fermentation conditions, the results obtained were: the initial fermentation pH was between 6.8 to 7.2, speed at150 r/min, culture temperature at 24℃, incubation time 3 d, 10% inoculum which produced the highest extraction rate of polysaccharide.The response surface analysis methodology (RSM) was used for optimizing extraction conditions in the extraction process of polysaccharides from Cordyceps Minlitaris L.Lik and Coriolus versicolor(L.ex Fr.) Base on the single-factor experiments, three independent variables, extracting time, solvent-solid ratio and xtraction temperature, were selected as casual factors during extraction. The experiments were arranged according to Box-Behnken central composite experiment design. The results showed that the optimum extraction conditions for polysaccharides of Cordyceps Minlitaris L.Lik were as follow: extraction time 2 hours and 3 minutes, solid-liquid ratio of 57:1(mL:g) and extraction temperature: 82℃.The maximum predict response at this time was 0.398984%. Standard error was 0.006626%. Validation tests confirmed that the model error was 1.26%, within the allowable range. The optimal extraction conditions of Coriolus versicolor(L.ex Fr.) were : extraction temperature 81℃, the solid-liquid ratio of 53:, extraction time 2 hours and 40 minutes. The maximum extraction rate was 0.383%. Model error was 2.09%, within the allowable range. The optimum extraction conditions of two mycelium were close, in order to save time and reagents, we could also extract them at the same time. The best conditions were: extraction temperature 81℃, solid-liquid ratio of 55:1, extraction time of 2 hours and 30 minutes.The acute toxicity test of Cordyceps Minlitaris L.Lik and Coriolus versicolor(L.ex Fr.) showed that the median lethal dose LD50 was greater than 15 g/kg. This showed that the compound was non-toxic level.The typeâ…¡diabetes model inducing by STZ, the success rate of which was 86.25%, to meet the test requirements.The hypoglycemic effect of the compound showed that it dould significantly alleviate the hyperglycemia in diabetic mice, and the effect was more significant than use Cordyceps Minlitaris L.Lik or Coriolus versicolor(L.ex Fr.) alone.