| Nowadays,fungi resources have been utilized in all respects in our everyday life and been the focus of life science researches.Bioactive compounds derived from fungi have huge bioactivities and enable to inhibit bacterials broadly.Inonotus obliquus(I.obliquus)is a white rot fungi that can be edible and traditional medicinal use and viewing as a kind of folk remedy in China,Russia,and other Baltic countries.Many bioactivities of I.obliquus have been identified including antibacterials.However,the natural resource of the I.obliquus is limited and thus the submerged fermentation is preferred to obtain the so many components we want.In this study,various fractions were prepared and isolated by bioassay-guided.Under the submerged fermentation with lignocellulose added,By means of liquid-liquid extraction,D101 macroporous adsorption resin,and silica gel column chromatography,subfraction of the first part out of D101 macroporous adsorption resin derived from ethyl acetate extracts(D101-Fr.1)were found the most harmful to Staphylococcus aureus(gram-positive),the part1 via silica gel column chromatography from the ethyl acetate extracts(SG-Fr.1)showed the best effect on Escherichia coli ATCC 6538(gram-negative).Further,sub-fermented polyphenols from I.obliquus had a much longer effect on all the strains than ampicillin,this researches may be useful in the search of antimicrobials of I.obliquus deeply and the potent application widely.In this paper,the antimicrobial activity of extracellular products,ethyl acetate,nbutanol and the water parts and the fractions by macroporous adsorbent resin and silica gel adsorption chromatography divided from the fermented liquid of I.obliquus were tested.Antimicrobial activity of the all preparations targeting Escherichia coli(ATCC8099),Bacillus subtilis(ATCC 6051),Enterococcus faecalis(ATCC 29212),Streptococcus pneumonia(ATCC 49619)and Staphylococcus aureus(ATCC 6538)were screened by determining the values of inhibition zone diameter IZD(mm),minimal inhibitory concentration MIC and minimum bactericidal concentration MBC(mg/m L),and the anti-biofilm ratio BF(%),Seneral significant results were concluded:D101-Fr.1 was picked out the most efficiency against Staphylococcus aureus(ATCC 6538)from all the isolations and with the IZD(mm)was up to 18.67±2.52 under the 200 mg/m L concentration,Meanwhile,the MIC and MBC(mg/m L)were measured0.39 and 0.78 respectively.Regarding the anti-biofilm assay of D101-Fr.1,the maximum inhibition(65%)to initial bacteria cell attachment was observed below the 2MIC(0.78 mg/m L).However,no further increase but a decrease in inhibition was observed at higher D101-Fr.1concentration.The best destruction of preformed biofilm was up to 67% at 1/2 MIC concentration of 20 mg/m L which much lower than that in the initial bacteria cell attachment assay,and thus suggesting that D101-Fr.1 was even more active in destroying the preformed biofilm at lower concentrations than it was in inhibiting the biofilm formation.SG-Fr.1 showed better bacteriostatic effect on the harmful bacteria of the intestinal microbiota(Escherichia coli ATCC 6538).The IZD(mm)was measured 17.00±7.00 under the 200 mg/m L concentration,and the MIC and MBC were measured at 0.39 and0.78mg/m L respectively.As the maximum inhibition to initial bacteria cell attachment,SG-Fr.1was observed of 59% below the 2 MIC of 0.78 mg/m L.No further increase was seen at the higher concentration.The destruction of preformed biofilm was ranged from 0.3% to9.0%,which suggesting that SG-Fr.1was mostly works by suppressing the initial bacteria cell attachment and not the inhibition of the preformed biofilm.Compared to the ampicillin,sub-fermented polyphenols from I.obliquus had a much longer effect on all the strains.The HPLC results of D101-Fr.1 and D101-Fr.1-1 showed that there seemed to be synergistic effect between the components in D101-Fr.1 to inhibit the bacteria. |
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