Study On The Extraction Method Of Lavender Essential Oil And Antibacterial Activity Against Bacillus Subtilis Based On Composition-Activity Relationship

In this paper,the efficient extraction method and antibacterial activity of lavender essential oil were studied.The lavender samples were collected from Yili Xinjiang as the research objects,fingerprints analysis method of essential oil in lavender by gas chromatography-mass spectrometry?GC-MS?was established that it could be rapid and accurate to evaluate the quality of lavender essential oils.Static headspace coupled with GC-MS and Fe₃O₄ sphere-assisted microwave distillation?MD?coupled with ionic liquid-based headspace single-drop microextraction?IL-HS-SDME?followed by GC-MS were developed for the analysis of volatile compounds in dried lavender.Chemometrics method was applied to identify the characteristic markers that contributed greatly to cultivar differentiation.Antibacterial activity of lavender essential oil against Bacillus subtilis was evaluated,chemical compound of the lavender essential oil were identified using GC-MS,the composition-antibacterial activity relationship model of essential oil was established to find the active compounds that inhibit Bacillus subtilis in essential oils.The main details are as follows:?1?This study aimed to establish a fingerprints analysis method of essential oil in lavender for quality control by GC-MS.Twenty-one samples collected in Xinjiang which belong to two different lavender varieties of French blue and C-197?2?were analyzed by GC-MS,identification of compounds was based on the retention indices and mass library.Twenty-six peaks were selected as the common peaks in fingerprint.Samples for training set in pattern recognition by partial least-squares discriminant analysis?PLS-DA?.Potential biomarkers screening was performed according to VIP value.Through the forecast of 7 unknown samples in the PLS-DA model,the root mean square prediction error of two kinds of lavender oil samples were 0.1323,the discrimination accuracy for the lavender varieties was 100%by PLS-DA model based on the validation set of samples.The results show that the established method could be rapid and accurate to evaluate the quality of lavender essential oils.?2?This study aimed to develop a rapid and accurate analytical method for discriminating three lavender varieties?French blue,H-701,and C-197?2??that could not be easily distinguished by volatile compounds.A total of 22 lavender samples from three varieties were analyzed by static headspace?HS?coupled with GC-MS.The experimental parameters including equilibrium time,equilibrium temperature and water addition were investigated.The optimal analytical conditions were as follows:a water volume of 2 m L,an equilibrium time of 20 min,and an equilibrium temperature of 90?.Using the proposed method,a total of 26 compounds in the lavender were identified.The results were further processed with a discriminative study by HCA and PCA to detect clustering formation and to establish the relationships between varieties and their volatile components.These varieties were clearly differentiated according to the results of HCA and PCA.These results suggested that static HS-GC-MS coupled with HCA and PCA is a feasible and rapid technique to differentiate lavender varieties with similar morphological characteristics.?3?In this work,Fe₃O₄ sphere-assisted microwave distillation?MD?coupled with ionic liquid-based headspace single-drop microextraction?IL-HS-SDME?followed by GC-MS was developed for the analysis of essential oil in dried lavender.The Fe₃O₄spheres were used as microwave absorption medium for dry distillation of dried lavender.A home microwave oven without any modifying was used in the MD-IL-HS-SDME.The effects of the experimental parameters were investigated.The optimal analytical conditions were:extraction solvent of[C₆mim]BF₄,single-drop volume of 2?L,irradiation time of 5 min,extraction time of 20 min,sample amount of 30 mg and the addition of 5 mg Fe₃O₄ to sample.The developed method was successfully applied to analyze 12 samples of three varieties of lavender.A total of 36compounds were identified by the proposed method.PCA was used to differentiate lavender varieties,according to the variety of different lavender samples were clearly separated.The results showed that the Fe₃O₄ sphere-assisted MD-IL-HS-SDME is a fast,sensitive,low cost and small sample consumption method for the determination of the essential oil in dried plant materials.?4?The lavender essential oil components were analysis by using GC-MS.PLS was used to construct a chemical composition-antibacterial activity relationship model of lavender essential oils,and to find out the active compounds that inhibit Bacillus subtilis in lavender essential oils.A total of 39 compounds were identified by GC-MS analysis combined with NIST library search and retention index from the literature for qualitative analysis of essential oil components.The antibacterial activity of lavender essential oil against Bacillus subtilis were determined by filter paper diffusion method.The inhibition zone diameter of the essential oil against Bacillus subtilis were between 9.8 mm and 13.8 mm,the result showed that lavender essential oil had a certain antibacterial activity against Bacillus subtilis.The IC₅₀ value of lavender essential oil against Bacillus subtilis was determined by plate colony counting method,which value from 1.35%to 2.43%.The chemical composition-antibacterial activity relationship of lavender essential oil was investigated by PLS analysis.The results showed linalool and linalyl acetate were the largest contribution of biological active compounds against Bacillus subtilis,the rest are terpinene-4-ol,caryophyllene and?-terpineol.