Preparation And Antibacterial Activity Of Allicin Substances

Garlic has strong antibacterial effect and its main active ingredients are some propylene sulfide substances, commonly known as allicin, which can be extracted from garlic or obtained by chemical methods of synthesis. I have done a series of studies, including the extraction of allicin in garlic:allicin chemical synthesis、the inhibitory effect of allicin and allicin derivatives synthesis. The results are as follows:(1) Extraction of garlic allicin was done by using ultrasonic assisted method. Through the comparison and analysis of the two different types of ultrasonic devices, I found the optimal extraction conditions:Using the probe type ultrasonic cell pulverizer, the work of intermittent ratio of3:1, the ultrasonic power500W, ultrasonic time50min, liquid ratio of4:1, the extraction rate in more than79%.(2)Studies of ultrasound assisted synthesis of allicin were conducted respectively with the "sodium thiosulfate-sodium sulfide" method and the "over-sulfide phase transfer catalysis" method. Synthesis allicin A (the composition is more complex) and synthetic allicin B (diallyl disulfide content accounting for more than90%) were obtained. Two synthetic methods of the optimal conditions were determined by experiment."Allyl chloride-sodium thiosulfate-sodium sulfide" method for optimal synthesis conditions are:ultrasonic power250W, the Moore ratio between allyl chloride and sodium thiosulfate being1.00:1.20, the reaction temperature45℃, ultrasonic time40min, reaction time2.5h, crude yield of83%or more. If the ultrasonic assistance was used along with the sulfide phase transfer catalysis, then phase transfer catalyst becomes unnecessary. The optimal synthesis conditions of this method are:fixed ultrasonic power250W, ultrasonic time50min, the reaction time3.0h, the reaction temperature40℃, Moore ratio between allyl chloride and sodium sulfide being1:0.7, the yield of more than72%.(3) The antibacterial tests on natural allicin, synthetic allicin A and synthetic allicin B were carried out. Experimental results show that three allicins can inhibit, to a certain degree, the four common bacteria: aspergillus, yeasts, staphylococcus aureus and escherichia coli. In addition, the MIC (minimum inhibitory concentration) experiments with synthesis allicin B has proved that the MIC of the synthetic allicin B for Staphylococcus aureus and that for yeast are both1mg/mL, and that the MIC for E. coli is2mg/mL. Rhizopus spores antibacterial experiments have proved that when the concentration of synthesis allicin B is1mg/mL, the germination rate of Rhizopus spores can be reduced by33.33%. Rhizopus spore growth is completely inhibited when the concentration of the synthetic allicin B is2mg/mL.(4) In addition, through ultrasonic assisted "sodium sulfide" method eight allicin substances were synthesized. In addition, the MIC experiments with these substances has proved that these substances are mostly the same with allicin has antibacterial effects.