| Chimonanthus nitens Oliv.also known as Maoshan tea,has a long history as a traditional beverage in China.Moreover,Chimonanthus nitens Oliv.essential oil(named CEO)is considered as one of its main components.In the present study,the microwave-assisted steam distillation extraction was used to prepare CEO and the procedure was optimized by orthogonal design,and then gas chromatography-mass spectrometry(GC-MS)was applied to identified the chemical components of CEO.In addition,the antioxidant activity of the essential oil was evaluated by taking1,1-diphenyl-2-picrylhydrazyl(DPPH)radical,reducing power and chelating ability of metal ions as indicators.Subsequently,intraperitoneal injection of LPS were employed to establish the in vivo model of acute lung injury(ALI),and the possibility of CEO against ALI caused by LPS was investigated.The main conclusions of this study were listed as follows:1.The optima extraction conditions were 10 min of microwave application,extracted 25 times with ultrapure water,along with 5 h of steam distillation time.In this conditions,the extraction rate of CEO was 1.78%.Furthermore,a total of 21 chemical compounds were identified in CEO,which contain lipids and terpenoid,among them,(1-methyl-4-propyl-1-ene-2-cyclohexyl)acetate was 50.665%,followed by α-pinene(6.92%),α-terpinyl acetate(5.77%),humulene epoxide II(3.96%),pseudolimonen(3.21%)and germacrene D(3.12%).Moreover,antioxidant activity analysis indicated that CEO possessed certain antioxidant activity.Briefly,the IC50 of the essential oil involved in the DPPH free radical scavenging assay,was 87.00mg/m L.Furthermore,the reduction force of the essential oil could be achieved to the level of the positive control group,when its concentration was 10 mg/m L,and the half inhibition concentration of the chelating ability of metal ions was 17.60 mg/m L.2.CEO could protect rats against ALI,as evidence by increasing white blood cell count,reducing immune organ index and improving lung histopathological changes in rats subjected to LPS.Reduction of the levels of IL-1β was also shown during CEO-triggering lung protection in rats.Further data presented that the expression of Toll-like receptor 4(TLR4)and Nuclear factor-κB(NF-κB)p65 were significantly attenuated in lung tissue subjected to CEO,suggesting that inhibition of TLR4/NF-κB signaling pathway devoted to its lung protection.Meanwhile,these protective effects of CEO were accompanied by the attenuation of lipid oxidation,and elevation of antioxidant enzymes,suggesting that enhancement of antioxidant defense was linked to the lung protection mediated by CEO.3.CEO could ameliorate ALI rats by improving intestinal status.In this work,CEO pretreatment significantly improved the intestinal morphology indicating CEO-induced lung protection was in association with its beneficial role in the intestine of ALI rats.Moreover,the intervention of CEO significantly elevated short-chain fatty acids(SCFAs)in LPS-induced ALI rats.Meanwhile,CEO could maintain the microbial structure in the intestine of rats,modify the characteristic bacteria in the intestine by downregulatig the relative abundance of Akkermansia to normalize the intestinal microbiota,which were contributed to CEO-mediated lung protection. |
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