| Siraitia grosvenorii is one of the first approved materials of food and drug in China.It is usually used as a raw material for extracting mogrosides in industry,and the residues of S.grosvenorii are often a waste due to insufficient utilization of the active ingredients.Therefore,it is very important to develop the high-value biotechnology for the residue utilization.White-rot fungi can degrade and transform the lignincellulose with highly efficiency due to the unique ligninolytic enzymes.There are few previous literatures reported that WRF could enrich and transform of the active substances in the residue of S.grosvenorii and improve the intestinal health.Based on this,in this project,Schizophyllum commune was employed to biotransform the residue of S.grosvenorii.And then we assessed the bioactivities of the fermentation products,such as the anti-tumor activity,the probiotic function,and the antioxidative function.The bioactivity of the main substances derived from fermentation products have been preliminarily illuminated.The conclusions of the full text are as follows:1.The fermentation products derived from S.grosvenorii residue transformed by S.commune possess anti-tumor activityTo screen the edible and medicinal fungi which are able to ferment the S.grosvenorii residue and Pueraria lobata residue,four fungi were selected.As a result,the fermentation products derived from S.grosvenorii residue transformed by S.commune(8 days)showed a significant inhibitory effect on SW480 cells.The cell viability of SW480 cells could be significantly reduced to 0.17% after 1mg/mL fermentation products treatment for 48 h.The fermentation products did not show inhibitory effect on L02 cells.Then we found that the inhibitory effect is related to the induction of apoptosis.With the addition of 0.8 mg/mL fermentation products for 24 h,the apoptosis rate of SW480 cells reached 16.97%,which was 4.5-times in comparison with the untreated SW480 cells.Based on the analysis of transcript level of Bcl-2 family genes,the fermentation product induced apoptosis by up-regulating Bax gene and down-regulating Bcl-2 gene.2.The fermentation products derived from S.grosvenorii residue transformed by S.commune have probiotic effect and antioxidative function.Lactobacillus acidophilus and Lactobacillus helveticus could utilized the fermentation products and showed the strongest effect on the short-chain fatty acids production.The total short-chain fatty acids content reached 1.01 mmol/L and 1.00 mmol/L,respectively.The antioxidative function of the fermentation products showed a dose-effect.The maximal antioxidative function of fermentation products was observed in 10 mg/mL,and the removal rates of DPPH free radicals,hydroxyl free radicals and ABTS free radicals reached 92.44%,80.56% and 99.34%,respectively.3.Isolation and functional verification of the fermentation products derived from S.grosvenorii residue transformed by S.communeTo isolate the extracellular active substances from the fermentation products derived from S.grosvenorii residue transformed by S.commune,the substances from the fermentation products were isolated and purified by graded ethanol precipitation.The graded ethanol precipitation products in corresponding control groups(water extract of S.grosvenorii residue and the supernatant of S.commune cultured in synthetic medium)showed no anti-tumor activity.However,the products at the corresponding ethanol precipitation concentration(60% and 80%)showed an obviously inhibitory effect on SW480 cells.Meanwhile,the inhibitory ratio of SW480 cells reached about 80% with the treatment of the ethanol precipitation concentration(60% and 80%)products.The ethanol precipitation products also showed a significant protective effect on oxidatively damaged L02 cells.In the presence of these products(0.2 mg/mL),the cell viability of oxidatively damaged L02 cells reached more than 80%.In addition,the 60% ethanol precipitation products have a stronger probiotic effect than the fermentation products.The verification of the biological function was performed by purification of the crude polysaccharides.The polysaccharides contents in 60% and 80% crude ethanol precipitation products reached 850.95 mg/g and 404.68 mg/g,respectively.Compared with the crude polysaccharides in water extract of S.grosvenorii residue,the polysaccharides contents increased,respectively.Compared with the crude polysaccharides in the supernatant of S.commune cultured in synthetic medium,the polysaccharides contents increased,respectively.Compared with the inhibitory ratio(80%)in the presence of the crude polysaccharide,the crude polysaccharides showed a more significantly inhibitory effect on SW480 cells,and the inhibitory ratio of SW480 cells reached about 85% with the addition of 0.8 mg/mL crude polysaccharides.While the polysaccharides purified from the control groups(water extract of S.grosvenorii residue and the supernatant of S.commune cultured in synthetic medium)did not show the anti-tumor activity.The crude polysaccharide(60% ethanol precipitation)showed a higher probiotic effect than the crude polysaccharide(80% ethanol precipitation)for 5 Lactobacillus species.The antioxidative function of the two crude polysaccharides has also been improved.The DPPH free radicals,hydroxyl free radicals,and ABTS free radicals could be almostly eliminated in the presence of the two crude polysaccharides at the concentration of 4 mg/mL.This study firstly found that the additional value and biological function of S.grosvenorii residue which is transformed by S.commune could be significantly improved.The fermentation products derived from S.grosvenorii residue transformed by S.commune exhibited a variety of biological activities,including the inhibitory effect on colorectal cancer cells,the probiotic effect on Lactobacillus species,and the antioxidative function.The project provided theoretical support for the potential application of the biological activity of the resources of S.grosvenorii in the development of prebiotics and anti-tumor activity. |
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