| RCEF260 is a valuable strain of Acremonium implicatum (Gilman & Abbott) Gams for medicinal use, isolated from Cordyceps gunnii var. minor. The primary experiment has revealed that its aqueous extract has obvious effects of liver protection based on IR model, and that the main functional components are nucleosides. In order to provide proof for medicine exploitation of the nucleosides, the liver-protection mechanism of the extract on injured mice, isolation and purification of the nucleosides; the effects of different extraction conditions on the nucleosides and liquid fermentation techniques were studied in the thesis.In the immune and chemical liver damage model, different dosages of aqueous extract from RCEF260 mycelium all significantly declined the raised levels of ALT, AST and MDA in livers of injured mice induced by BCG+LPS, CCl4 and D-GalN and raised the activity of SOD. Meanwhile, the raised activities of TNF-α and IL-I induced by BCG+LPS were reduced. The results showed that the aqueous extract exerted evident protective effect on liver and that the effect was dosage dependent.Aqueous extraction tests showed that the yield of nucleosides from RCEF260 mycelium was 15.93%. The extract was analyzed with TLC, HPLC and MS, and the results showed that there were several kinds of nucleosides in the extract, and the compositions of the nucleosides were as following: uridine 21.14%, xanthosine 10.42%, cytidine 17.77%, thymine 2.11%, Thymidine 12.59%, adenosine 6.69% and0 cordycepin 1.34%. The extract was further iaolated with LC and purified with preparative HPLC, and uridine, adenosine, and thymidine were obtained. The general content of nucleosides in the wet mycelium and mycelial powder by different extraction methods were compared, including methods of microwave, enzyme, autolysis, acid-heating, ultrasonic and freezen-resolving. The results suggested that treatment time in the methods of enzyme and autolysis was too long, and the acid-heating was easy to cause denaturalization. Microwave treating for 4min was therefore selected as the optimal method for wet mycelia.In order to optimize a drying method of wet mycelia produced in fermentation, different drying methods and drying temperature were compared, including freeze drying and oven drying at 40℃-70℃. The results showed that oven drying at 55℃-65℃ were comparable suitable , and the yield at such temperature was obviously higher than that at 40℃ and freeze drying. In conclusion , the method of the oven drying at 55℃-65℃ was the optional way for convenient operation in industry with low cost. Comparison of extracting temperature, solvent type, solvent-mycelial ratio and extracting time in water bath, the optimum extraction condition was determined as follows: immerge the mycelia powder in 5 time volume of 50% ethanol, reeling extraction at 50℃ for 60 minutes.A series experiments were conducted including screening of carbon and nitrogen resources, inorganic salt, vitamin, initial value of pH of medium, fermentation temperature and orthogonal tests. The optimum liquid medium for industrial fermentation of the strain RCEF260 was determined by comparing the content of nucleosides. The main components of the medium were as follows: bran 3%, glucose 1%, bean powder 3%, yeast power 2%, MgSO4 0.02%,K2HPO4 0.06% and compound vitamin 0.05%.Different Cordyceps mycelial powders were compared and the results showed the content of nucleosides from RCEF260 mycelia powder was higher than those from Cordyceps sinensis and Hirsutella sinensis.
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