Cytotoxicity Of Saponins From Schima Superba On Magnaporthe Oryzae

The paper was following previous research in our laboratory, the extraction process of activity saponins from Schima superba against Magnaporthe oryzae was optimized with single factor and orthogonal experiment, and we determined the toxicity effects about saponins from Schima superba against the different types of cells from Magnaporthe oryzae by microscopic observation, hemacytometer counting method and infection in vivo tests and other methods. In order to determine the leads of activity saponins from Schima superba against Magnaporthe oryzae, and develop new blasticidin reagent of saponins.The extract process of activity saponins from the leaves of Schima superba against Magnaporthe oryzae as follows:alcohol concentration of60%, solid-liquid ratio of1:8, extraction temperature of55℃, extraction time of5hours in the first times, and the second times, solvent quantity and time were both in half, and in the process of extraction can be appropriately to stir to speed up the extraction effect. Nine kinds of saponins were R2-A, R2-1, R2-B2, R2-2, R2-3, R3-1, R3-3, R3-4and R3-5, they have been separated from Schima superba, and the toxicity effect on Magnaporthe oryzae was in different strength. The EC50of nine saponins against Magnaporthe oryzae spore germination were2.73,2.27,1.27,0.61,0.95,6.81,4.19,4.68,4.19μg/mL, the inhibition effect of saponins to Magnaporthe oryzae spore producing appressorium were78.68%,93.27%,92.00%,93.27%,91.93%,12.48%,43.71%,36.34%,22.34%, and the minimal inhibitory concentration of appressorium melanin were7.0,6.0,5.5,4.0,6.5,9.0,15.0,9.0,15.0μg/mL. Then EC50of the commercially available pesticide named isoprothiolane against Magnaporthe oryzae spore germination was13.94μg/mL, the inhibition effect of spore producing appressorium was9.11%, on the appressorium melanin of MIC was18μg/mL. The antimicrobial activity of nine kinds of saponins against Magnaporthe oryzae were stronger than the market sales of pesticide named isoprothiolane. The toxicity of Schima superba saponins against Magnaporthe oryzae mainly as follows:After the medicine, most of spores germination vigor decrease; Few spores only cause germ tube, but cannot be further germination to appressorium, the appressorium number was reduction obviously, narrow diameter and adherent intracellular accumulation of pigment to reduce, or even atrophy, hollow, transparent, it was difficult to form a high pressure permeability nail, which blocking the spread of Magnaporthe oryzae to infect. The structural integrity of cell membrane and wall were destroyed, mycelium were swelling, cracking and other anomalies, and inclusions such as sugar, protein in the body were leaked to cause cell death. Different structure of saponins from Schima superba on inhibition of different types of Magnaporthe oryzae cells were different, and the antibacterial activity of R2-1, R2-2and R2-3against Magnaporthe oryzae was most intense, so they were the active leads of the Schima superba against Magnaporthe oryzae.