Study On The Activities Of Neroli Essential Oil And Preparation Of Its Microcapsules

Backgrounds and Objective: Citrus Aurantium L.is a small evergreen tree in the Citrus genus of Rutaceae,which is native to Algeria,Spain and many other countries.The neroli essential oil was extracted from neroli flower petals by distillation method,and the main components are limonene,linalool,etc.It can relieve nausea,indigestion,constipation and other symptoms.It also has the application effects of calming and inhibiting appetite,antibacterial,anticonvulsant,calming and anti-inflammatory,stimulating cell activity,eliminating peculiar smell,softening skin tissue,eliminating pigment deposition,maintaining skin tissue moist and so on.It is widely used in the aroma industry.However,there are few basic studies on its pharmacological activity,and neroli essential oil is volatile and unstable,so it is necessary to develop new formulations that can protect the stability of neroli essential oil.In this paper,the chemical constituents of neroli essential oil were studied and their in vitro activities were determined,and the therapeutic effect of neroli essential oil on acute peritonitis in mice was discussed.The essential oil of neroli was prepared into microcapsules,and the preparation process conditions were optimized.Methods: Gas chromatography-mass spectrometry（GC-MS）was used to analyze the chemical constituents of neroli essential oil.The antiallergic activity of neroli essential oil was determined mainly by the Morgan-Elson method.The whitening activity of neroli essential oil was determined by tyrosinase inhibition rate.The in vitro antibacterial activity of neroli essential oil was detected by the zone of inhibition method.Using lipopolysaccharide（LPS）as an inducer,mouse RAW264.7 cells were induced to establish an inflammation model.Interleukin-1β（IL-1β）,interleukin-6（IL-6）secreted by cells and tumor necrosis factor alpha（TNF-α）were detected by enzyme-linked immunosorbent assay（ELISA）.Lactate dehydrogenase（LDH）activity and malondialdehyde（MDA）content in mouse intestinal tissue homogenate were determined by using corresponding kits.The mouse intestinal tissue was stained with hematoxylin-eosin（H＆E）and its pathological characteristics were observed and analyzed.The protein electrophoresis was used to detect the expressions of NF-κB P65 and IκBα in intestinal tissues.The encapsulation process of neroli essential oil microcapsules was optimized by single factor test method and response surface methodology（RSM）.The microcapsules of neroli essential oil were characterized by scanning electron microscopy（SEM）,dynamic light scattering（DLS）,Fourier transform infrared spectroscopy（FT-IR）and other methods,and their in vitro drug release properties were analyzed and evaluated.Results: The results showed that there were 36 chemical components in neroli essential oil,among which the main compounds were alcohols,terpenes and esters.Neroli essential oil has different degrees of inhibitory effect on five bacteria including Escherichia coli and Streptococcus agalactiae,and can also affect LPS-induced RAW 264.7 cells,inhibiting IL-1β,IL-6 and TNF-α secretion.It indicated that neroli essential oil had in vitro antibacterial and anti-inflammatory activities.It was found that neroli essential oil improved intestinal tissue injury,reduced the levels of inflammatory factors IL-6 and TNF-α,enhanced the activity of LDH,reduced the content of MDA,and effectively inhibit the activation of NF-κB signaling pathway in mice with acute peritonitis.The optimal encapsulation conditions of neroli essential oil microcapsules were as follows: the concentration of chitosan was1%,the dosage of emulsifier was 1.6%,the ratio of shell to nucleus was 2:1,and the emulsification rate was 2000 rpm.The optimized neroli essential oil microcapsules were spherical,with smooth surface,continuous dispersion and smooth spherical shape,and the particle size was about 2.3μm-2.6μm.The release behavior in vitro showed that neroli essential oil microcapsules were stably released for 72 h at p H 7.4.Conclusions: Neroli essential oil has complex chemical composition and has whitening,anti-allergy,antibacterial and anti-inflammatory activities in vitro.By inhibiting the activation of NF-κB signaling pathway,reducing the level of inflammatory factors in mice with acute peritonitis has a therapeutic effect on acute peritonitis.Neroli essential oil microcapsules prepared by chitosan have good quality and stable properties.The results provide important theoretical basis for the development and utilization of essential oil and the discovery of new drugs for the treatment of peritonitis.