Antibacterial Activity And Mechanism Of10-HDA Against Gram-positive Bacteria

10-Hydroxy-2-Decenoic Acid (10-HDA) is one of sign matters in the bee royaljelly, approximately composes is1.4%-2.0%of the bee royal jelly, its structuralformula is HO-CH2-(CH2)6-CH=CH-COOH (C10H18O3).10-HDA has baceriostasisactivity, the enhancing immunity, the anti-radiation, falls the blood fats and so on.Although10-HDA has strong antifungal activity, few or no literatures reported theinhibiting mechanism of10-HDA against bacteria now. At present, the inhibitingmechanism of10-HDA against Bacillus subtilis, Staphylococcus aureus will be studiedusing electron microscopy and biochemistry techniques. The main results andconclusions were given as follows:1、Determining the biological activity of10-HDAThrough using oxford cup test and half dilution method for testing antibacterialactivity, the antibacterial activity of10-HDA were identified and analyzed in this study.The results indicated that,10-HDA which showing a broad spectrum of antimicrobialactivity has obvious inhibition effects on multiple pathogenic bacteria with aconcentration-depended mode of inhibitory effect. And the minimum inhibitoryconcentration (MIC) against Staphylococcus aureus and Bacillus subtilis was0.62mg/mL.2、 Effects of10-HDA on cell membrane and metabolic activities ofStaphylococcus aureusThe antibacterial mechanism of10-HDA against Staphylococcus aureus wasstudied according to the effect of10-HDA on the growth curves, membranepermeability, the structure under scanning electron microscope, and respiratorymetabolism. The experiments showed that10-HDA could increase membranepermeability of Staphylococcus aureus, which led the macromolecules with ultravioletabsorption to leak out of the cell. And the metabolism of Staphylococcus aureus wasdisarranged by10-HDA.3、Effect of the genomes and protein synthesis of10-HDA against StaphyloccousaureusBacillus subtilis was regarded as research object for observing the quantity andbonding of DNA with effect of10-HDA, as well as the impact of10-HDA on PCR byusing atomic force microscope (AFM) and agarose gel electrophoresis of DNA.Agarose gel electrophoresis and AFM analyses revealed that the synthesis of DNA was rapidly decreased due to the close combination with10-HDA. It was further proved bythe research about the impact on PCR of DNA that the synthesis of DNA could becompletely impeded when the mixing concentration of10-HDA was1.0mg/mL.In summarize，we can draw the conclusion about the inhibiting mechanism of10-HDA against gram-positive bacteria. The10-HDA can enter into the organism cellwhen the Staphylococcus aureus and Bacillus subtilis was treated with10-HDA. Thenthe10-HDA could disrupt the cell membrane which caused an enormous number ofmaterials to leak out of the cell. Even after tihis, the10-HDA combined with DNA andinhibiting the expression of this gene. These changes could suppress cell growth andfinally result in death.