Preparation of lactonic extract from Elephantopus scaber and its antibacterial effects in vitro

To investigate the antibacterial effects of lactones from Elephantopus scaber,a well-known Chinese herbal medicine,ku-di-dan,the crude extracts from E.scaber were prepared with 800mL/L ethanol and followed by purification with silica gel column chromatography and crystallization.The purified extract of lactones from E.scaber (PELES) was checked and identified by thin layer chromatography and its antibacterial effect in vitro was observed.2.0mg/mL of PELES inhibited the growth of Pasteurella multocida(PM) and Bacillus cereus(BC)(P0.05),and significantly inhibited the growth of Staphylococcus aureus(SA),Salmonella enteritidis(SE),and Escherichia coli in chicken(CC)(P0.01),respectively.PELES at 5mg/mL and 10mg/mL significantly inhibited(P0.01) the growth of all the five strains of bacteria(P0.01) and the minimum inhibitory concentration(MIC) of PELES was 0.313mg/mL against SA and SE and 0.156mg/mL against PM,0.625mg/mL against CC,and 1.25mg/mL against BC.Theminimum bactericidal concentration(MBC) of PELES against BC was 2.5mg/mL while the MBC against the other four bacteria was 0.625mg/mL.The result showed that PELES from ku-di-dan had significant antibacterial effects.