| Pleurotus tuber-regium is a kind of very precise edible and medicinal fungi,Which has been used as food or medicine for a long time in some countries of Africa.It also receives much concern in Yunnan Province of China because of its favorablepharmacological properties. The study on secondary metabolites from Pleurotustuber-regium broth is seldom reported. We focused preliminary on the antibacterialsubstances of Pleurotus tuber-regium broth in this study. The results are as follows：(1) The characteristics about extraction of Pleurotus tuber-regium by liquidfermentation fractions with different polar solvents indicated that the minimalinhibitory concentration (MIC) of yield extracted with acetic ether to Staphylococcusaureus was0.25mg/mL, which was lower than those extracted with other polarsolvents; The active compound extraction rate of acetic ether from Pleurotustuber-regium broth was25.2%, which was the high value among all extractionmethods. These results showed that acetic ether could extract active substanceeffectively and it was the best extract solvent.(2) The research results of antibacteria spectrum by the acetic ether extractionindicated: The acetic ether extraction had good antibacterial ability, which showedmore effective inhibit ability to G+than to G-, and no effect on Penicilliumcitrinumthom and Aspergillus flavus. The inhibition zone of extraction by acetic ether toStaphylococcus aureus is28.7mm at the concentration of0.5mg/mL.(3) Study on antibacterial mechanism of acetic ether extraction to Staphylococcusaureus indicated that the action site of the acetic ether extraction was located on cellmembrane. The process as follow: at first, the extraction was absorbed onto the cellmembrane and then destroyed the integrity of cell membrane, which led to thesplitting of cells and leaking of cell contents. Finally, the cell broke up and then died.(4) The comparisons of the antioxidant activity between extraction from myceliumand fermentation broth showed that the antioxidant activity of extraction from broth ishigher than that from mycelium. The clearance rate of 1,1-Diphenyl-2-picrylhydrazylradical2,2-Diphenyl-1-(2,4,6-trinitrophenyl)hydrazyl (DPPH) of extraction from fermentation broth was77.07%, which is higherthan that of extraction from mycelium. The highest clearance rate of.OH byextraction from fermentation broth was86.76%, indicating good activity. Throughmeasuring restoring force, we found that the restoring force of the extraction fromfermentation broth reached the high value of2.053, which was much higher than thatof mycelium at the concentration of2.5mg/mL.(5) It could be inferred preliminary by thin layer chromatography (TLC) that theactive compounds contain organic acids,steroid and fatty acid class and so on. Twokinds of compounds (A and B) were separated and purified by combining normalphase silica gel column chromatography with pressure in liquid by reversed-phasechromatography and antibacterial experiments. Compound A had antibacterial active,while another did not have.(6) We have identified two kinds of compounds by combining1H-NMR and13C-NMR with related papers. The compound A was2-furoic acid and the molecularformula was C5H4O3and molecular weight was112.08, which had antibacterial ability.The compound B was ergosta-7,22-dien-3β-ol and the molecular formula wasC28H46O and molecular weight was398.65, which did not have antibacterial ability.What is more, both of them were separated and purified from Pleurotus tuber-regiumbroth for the first time. |
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