Antimicrobial Activity And Component Analysis Of Nidus Vespae Extracts

Objective: To understand the extraction rate of different solvent extracts of nidus vespae and their antibacterial effect on different bacteria,to explore the stability of their antibacterial effect,to measure the minimum inhibitory concentration(MIC)and minimum bactericidal concentration(MBC),to observe the effect of different metal ion complexation on its MIC,and to analyze the specific components of the most stable nidus vespae extract.To provide reference for the development of related bee products in the future.Methods: The nidus vespae was extracted by ultrasonic extraction with 60%ethanol,absolute ethanol,ethyl acetate and petroleum ether,and the extraction rate was calculated.Four extracts were used for in vitro antibacterial tests against 11 bacterial species,and the inhibition zones were measured.The antibacterial stability of the four extracts was investigated with different p H,temperature,and UV irradiation time.The MIC and MBC of the best stable extract were measured,based on which different metal ions were added to observe the effect of different metal ion complexation on the MIC.Specific components of the most stable nidus vespae extracts were analyzed by gas chromatography-mass spectrometry(GC-MS)and triple tandem liquid mass spectrometry(LC-MS/MS).The measurement data in the results were analyzed by one-way ANOVA.Results: The extraction rate of 60% ethanol extract from nidus vespae was the highest,reaching 11.47%.All the four extracts had good antibacterial effects on Staphylococcus aureus,Staphylococcus epidermidis and Bacillus subtilis.Ethanol extract,60% ethanol extract,and ethyl acetate extract showed some antibacterial activity against Pseudomonas aeruginosa.The four extracts maintained good antibacterial stability under the same treatment time at different p H,temperature,and UV irradiation time,among which the ethanol extract had the best stability.The MIC and MBC of the ethanol extract against Staphylococcus aureus,Staphylococcus epidermidis and Bacillus subtilis were not higher than 3.125 mg/m L,and the addition of a small amount of copper ion and zinc ion could significantly reduce the inhibitory effect of the extract on Staphylococcus aureus and Bacillus subtilis.In this experiment,the composition analysis of anhydrous ethanol extract of nidus vespae by GC-MS and LC-MS/MS showed that there were 45 components with matching degree above 70 by GC-MS detection,and 126 components with matching degree above 70 by LC-MS/MS detection.Among them,there are a large number of fatty acids,flavonoids,terpenoids and other compounds that have been confirmed to have antibacterial effects.The main components of the gas phase component are hydrocarbons,and the main components of the liquid phase component are organic acids.The highest relative content of the gas phase component is heptacosane,and the highest relative content of the liquid phase component is usuolenic acid.Conclusion: The 60% ethanol extract of nidus vespae had the highest extraction yield.All the four extracts had antibacterial effects and good antibacterial stability.The ethanol extract of beehive had the best stability,with MIC and MBC less than 3.125mg/m L.Copper and zinc ions could enhance the antibacterial effects of the extracts on Staphylococcus aureus and Bacillus subtilis.The nidus vespae contains a large number of fatty acids,flavonoids,terpenoids and other compounds that have been proved to have antibacterial effects.The main components of the gas phase are hydrocarbons,and the main components of the liquid phase are organic acids.The results can provide a basis for the research of antibacterial effect of bee products.