| The useful substances from Loquat flower were extracted with different solvents such as ligarine,chloroform and acetic ether by supersonic and backstreaming method.Bacteriostasis were taken by perforated and cuvette method. It showed that the middle polar and less polar extracts had obvious effect to Staphylococcus aureus,Escherichia coli and Candida albicans with whose inhibition zones reach to 12～17mm and the bacteriostasis was dependent on its concentration.It indicated that the extracts mentioned above had good bacteriostatic effects.In order to explore the antibacterial extracts and their chemical composition,the ligarine extracts were separated by silica gel column and fractions M1～M24 were obtained.The bacteriostasis showed that the weak polarity fractions M1～M3 eluted by 100%ligarine had obvious bacteriostatic effect on Staphylococcus aureus,Escherichia coli and Candida albicans.The middle polarity fractions M7～M12 eluted by mixed solutions with ligarine:acetic ether 50:1～15:1 showed a good effect only to Candida albicans.The acetone extracts were separated by macroporous resin D101 and fractions D1～D6 were obtained.The bacteriostasis showed that fraction D3 eluted by 50%ethanol and fraction D4 eluted by 75% ethanol had a good effect only to Candida albicans.Since the bacteriostatic effects of segments M2 was the best,then further separation by low-temperature centrifugation of it were carried out and the A1 and A2 were obtained.The gas chromatography-mass spectrometry analysis were taken to M1,A1,A2,M3.It showed the main components of which were hydrocarbons n-C17～n-C27,which indicated some alkanes had good effects on the three kinds of bacterium mentioned above.Fraction A2 obtained by low-temperature centrifugation contained 2 major peaks which standed for C24 and C27 in GC-MS analysis.It showed the low-temperature centrifugation couldn be a good purification way of samples.The minimum inhibitory concentration(MIC) test were carried out to fractions M1,A1,A2,M3,D3 and D4 seperated from ligarine extracts.The result showed the numerical values of MIC to Staphylococcus aureus were 0.625 mg.mL-1,2.500 mg.mL-1,0.313 mg.mL-1,1.250 mg.mL-1.The numerical values of MIC to Escherichia coli were 0.625 mg.mL-1,2.500 mg.mL-1,0.625 mg.mL-1,0.625 mg.mL-1.The numerical values of MIC to Candida albicans were 0.625 mg.mL-1,1.250 mg.mL-1,0.625 mg.mL-1,1.250 mg.mL-1.The dams above showed that the purified sample A2 had a better bacteriostatic effects to the three kinds of bacteriums than the other tested samples,from which we could infer that the diolefines C24 and C27 could be the main ingredients accounting for bacteriostatic effects.D3,D4 had no bacteriostatic effects to Staphylococcus aureus and Escherichia coli.The numerical values of MIC to Candida albicans were 2.500 mg.mL-1,2.500 mg.mL-1.
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