Study On Lavender Essential Oil By SPME And Antibacterial Activity Against Escherichia Coli Based On Composition-activity Relationship

In this study,two sample preparation techniques of headspace solid-phase microextraction(SPME)and magnetic particles coupled with microwave assisted headspace solid-phase microextraction(MD-SPME)were developed for the determination of volatile components in lavender.Their components can be identified by gas chromatography/mass spectrometry(GC/MS).In order to distinguish the varieties of the lavender,the chemical components in the different lavender varieties were analyzed by multivariate statistical analysis.Antimicrobial activity of the lavender essential oil against Escherichia coli was evaluated,chemical components of the lavender essential oil samples were identified using GC/MS and,these two set of data were correlated using chemometrics methods.The composition–antibacterial activity relationship model of lavender essential oil was established to recognize the active compounds.1)The lavender has been widely used in food,aromatherapy,fragrant and pharmaceutical industries due to its unique chemical composition which confers both aromatic and biological activities.The objective of this study was to establish a method to fast identify the chemical constituents by solid phase micro-extraction-gas chromatography-mass spectrometry(SPME-GC/MS)and provide the basis for distinction of the different species by analyzing the remarkably different chemical components in the lavender.Based on the peak area of cis-?-ocimene,linalool,linalyl acetate,terpinen-4-ol,caryophyllene and caryophyllene oxide,three parameters(temperature,extraction time and desorption time)of headspace solid-phase microextraction(HS-SPME)were optimized,resulting in the best extraction condition including extraction temperature of 55?C,extraction time of 30 min and desorption time of 30 s.Twenty-six volatile compositions in lavender samples collected in Xinjiang which belong to three different lavender varieties were analyzed by GC/MS.Principal component analysis(PCA)and partial least-squares discriminant analysis(PLS-DA)were used to analyze the aroma profiles of the lavender.The results show that the chemical compositions in lavender from different varieties are clearly distinguished.Kinds of 9 chemical compositions are indentified as discrimination markers.This study can provide the basis for rapidly qualitative analysis of constituents and quantity control of the lavender2)In this work,microwave distillation(MD)assisted by magnetic Fe3O4 hollow microspheres(MFHM)and headspace solid-phase microextraction(HS-SPME)were combined,and developed for determination of essential oil components in dried lavender.The Fe3O4 were used as microwave absorption solid medium for dry distillation of dried lavender.Using the proposed method,isolation,extraction,and concentration of essential oil compounds can be carried out in a single step.The effects of the experimental parameters were investigated.The optimal analytical conditions were: fiber coating of 30 ?m DVB/CAR/PDMS,microwave power of 600 W,irradiation time of 15 min,and the addition of 5 mg Fe3O4 to the sample.Thirty-nine compounds in the essential oils of lavender were obtained and identified.Relative standard deviation(RSD)values less than 9% show that the present method has good precision.Principal component analysis(PCA)was used to differentiate lavender varieties and to identify discriminant varietal markers.The results showed that the MFHM-assisted MD-HS-SPME is a simple,rapid,reliable,and solvent-free technique for the determination of essential oil components in dried plant materials such as traditional Chinese medicine(TCM).3)The chemical composition–antibacterial activity relationship model of lavender essential oil based on gas chromatography/mass spectrometry(GC/MS)analysis was established to recognize the active compounds.Thirteen lavender essential oil samples in Xinjiang which belong to three different lavender varieties were analyzed by GC/MS.A total of 42 compounds were identified by mass spectral data and retention indices from the literature.Principal component analysis(PCA)was used to analyze the aroma profiles of the lavender essential oil.The PCA show that thirteen lavender essential oil samples were clearly distinguished three varieties.The IC50 value of lavender essential oil against Escherichia coli was determined by plate colony counting method,which value from 1.36% to 3.05%.The chemical composition-antibacterial activity relationship of lavender essential oil was investigated by partial least squares(PLS)analysis.The results showed that linalool,terpinene-4-ol,linalyl acetate,?-terpeneol and lavandulyl acetate were significantly related to antibacterial activity.Linalool was the largest contribution of biological active ingredients against Escherichia coli.