| Cinnamomum longepaniculatum leaves are rich in essential oil and therefore it was cultivated as an economic tree species in Yibin region of Sichuan province.Nowadays,traditional hydrodistilation is mainly used for the separation of C.longepaniculatum leaves essential oil,which has disadvantages of time and energy consumption as well as low yield.However,the utilization of C.longepaniculatum resource maily focuses on eucalyptol(content higher than 60%),its main constituent of essential oil,and other compounds are rarely involved.Therefore,a process route were designed for the effiitient and comprehensive utilization of C.longepaniculatum resources using C.longepaniculatum leaves as raw materials in this study.Micrwave assisted solvent free method was employed to extract of C.longepaniculatum leaves essential oil.On the basis of the laboratorial experimental results,a continious microwave assisited-steam distillation industrialized apparatus with 100 kg/h of sample throughput was designed for the extraction of essential oil and the scale-up experiment was carried out.Melt crystallization and rectification methods were used for the isolation of main compounds from the crude essential oil.The inhibitory activity of C.longepaniculatum leaves essential oil and its three main compouds(eucalyptol,?-terpineol and sabinene)were evaluated on three Fusarium spp.(F.culmorum,F.avenaceum,and F.sporotrichioides)which could cause dry rot,root rot,bakanae disease etc.Proanthocyanidins were extracted from the de-oiled C.longepaniculatum leaves,liquid chromatography-mass spectrometry(LC-MS/MS)was used to identify the phloroglucinolysis products to tentatively analyse their structures.C.longepaniculatum proanthocyanidins were separated as two parts,oligomer and polymer,the inhibition activity of C.longepaniculatum oligomeric proanthocyanidins on a-amylase,a-glucosidase and pancreatic lipase was also studied.Ultrasonic assisted antisolvent process was developed for the preparation of polymeric procyanidins microparticles.The physicochemical properties of obtained micromized polymeric procyanidins particles were characterized.In vitro antioxidant activity of the processed and umprocessed polymeric procyanidins were analysed.The residues after extracted two times were used for the preparation of sulfonated carbon.The structures and catalytic activity of the obtained sulfonated carbon were also investigated.The optimal conditions for the extraction of C.longepaniculatum leaves essential oil by microwave assisted solvent free method were eventually obtained with response surface methodology as follows:62%of C.longepaniculatum leaves moister content,19 min of microwave irradiation time,and 420 W of microwave irradiation power.Under the conditions mentioned above,the extraction yield of C.longepaniculatum leaves essential oil was 52.08 ±2.15 mg/g.The extraction kenetics and the enviormental impact of solvent free microwave assisted method on C.longepaniculatum leaves essential oil extraction was studied,the results showed that application of microwave irradiation on the extraction of C.longepaniculatum leaves essential oil possesses many advantages,including high extraction efficiency,saving extraction time,decreasing energy consumption,eco-benign,etc.Solvent free microwave assisted method was enlarged and a pilot stage method of continuous microwave-steam assisted approach was eventually designed for the extraction of C.longepaniculatum leaves essential oil,with which good extraction results was obtained.Gas chromatography mass spectrometer analysis was used to analyse the consitituents of the obtained essential oil,and the results revealed that the compositions of essential oil extracted by continuous microwave-steam assisted method were the same as solvent free microwave assisted method and each component just has slightly difference on their percentage content.Additionally,eucalyptol was the main consitituent and there are small amout of hydrocarbon compounds as well as alcohols contained in C.longepaniculatum leaves essential oil.According to the results,continuous microwave-steam assisted method is promising on the industrialized extraction of C.longepaniculatum leaves essential oil,which even could be up-scaled for the industrial scale extraction of plant essential oil.The antifungal activities of C.longepaniculatum leaves essential oil against three Fusarium spp.were stuied and the results suggested that C.longepaniculatum leaves essential oil showed srong antifungal activities on F.culmorum,F.avenaceum,and F.sporotrichioides.Methods of melt crystallization and rectification were employed to isolate eucalyptol,a-terpineol and sabinene from C.longepaniculatum leaves essential oil,respectively.Singer factor experiments results indicated the appropriate separation conditions for the isolation of eucalyptol by melt crystallization method were:4 ?/h of cooling speed,-30 ? of crystallization terminate temperature,5 ?/h of sweating speed,and-19 ? of sweating terminate temperature.Under the above conditions,the yield and purity of eucalyptol were 22.24 ± 1.02%and 84.78 ± 3.23%,respectively.Additionally,the inhibition activity of the three main components of C.longepaniculatum leaves essential oil were evaluated,results indicated that C.longepaniculatum leaves essential oil possessed high antifungal activities on Fusarium spp.not only depends to the effect of ieucalyptol,but also mainly rely on the synergistic effects of all the components contained in C.longepaniculatum leaves essential oil.According to these results,essential oil from C.longepaniculatum leaves could be having a promising application prospect in agriculture for the control of plant desease caused by the above methioned three kinds of Fusarium spp.Heat reflux method was employed for the extraction of C.longepaniculatum proanthocyanidins and the extraction yield was determined as 9.37 ± 0.32 mg/g.Proanthocyanidins were degraded by acid hydrolysis method in the presence of phloroglucin and the phloroglucinolysis products were tentatively identified by LC-MS/MS.The results demonstrated that catechin,epi-catechin and epi-catechin-3-O-gallate were recognized as the extension units,while catechin,epi-catechin,epi-gallocatechin,and epi-catechin-3-O-gallate were the terminal units of C.longepaniculatum proanthocyanidins.The calculated mean degrees of polymerization of oligomeric proanthocyanidins and polymer proanthocyanidins were 2.34 and 12.09,respectively.The inhibition activities of C.longepaniculatum oligomeric proanthocyanidins on digestive enzymes in vitro were evaluated and the results indicated that C.longepaniculatum oligomeric proanthocyanidins possess apparently higher inhibition activities than the positive control(acarbose and orlistat).Therefore,it was assumed that C.longepaniculatum has promising prospect as the source of natural digestive enzymes inhibitor.Ultrasonic assited antisolvent precipitation was designed to prepare micronized polymeric procyanidins.The optimizing preparation conditions of micronized polymeric procyanidins were obtained by both Plackett-Burman design and Box-Behnken design were obtained as following:polymeric procyanidins solution concentration 0.3 mg/mL,volume ratio of antisolvent and solvent 5,dropping speed 4 mL/min,precipitation temperature 10 ?,ultrasonic-stirring time 14 min,ultrasonic power 620 W,and stirring speed 760 r/min.The minimum mean particle size of micronized polymeric procyanidins was 96 ± 2 nm under the aforementioned conditions by the proposed approach.The obtained micronized polymeric procyanidins was characterized.It was observed that the micronized polymeric procyanidins by the improved method showed small,well-proportioned and globular morphology by scanning electron microscope(SEM).Meanwhile,the micromized processed polymeric procyanidins showed a smaller particle size than those of unprocessed polymeric procyanidins.Fourier transform infrared spectroscopy(FTIR)spectra analysis demonstrated that the chemical structures of polymeric procyanidins were not obviously influenced during the microparticles formation procedures.Thermogravimetric analysis(TG)analysis showed that the processed polymeric procyanidins presented a higher weight loss in comparing with the unprocessed samples in the increase of temperature from 150 ? to 550 ?.This may be because that the processed polymeric procyanidins possessed a higher specific surface and thus causing lower vaporization and early decomposition energy.X-ray diffraction(XRD)results demonstrated that the processed polymeric procyanidins enjoy an amorphous formal.The solubility test displayed that the solubility of micronized polymeric procyanidins was obviously improved.Micronized polymeric procyanidins have stronger antioxidant activity than the unprocessed samples.Therefore,the micronized polymeric procyanidins has a great potential application prospect in pharmaceutical and health care industrials.Secondary extraction residues of C.longepaniculatum were applied to preprare sulfonated carbon.The results of XRD indicated that the structure of prepared sulfonated carbon is amorphous carbon.FTIR analysis,elemental analysis,and X-ray photoelectron spectroscopy were revealed that the sulfonic acid group(-SO3H)were successfully inctroduced on the surface of sulfonated carbon.The result of TG analysis showed that the prepared sulphonated carbon of C.longepaniculatum enjoys good thermal stability under 250 ?.The obtained sulphonated carbon was applied to catalyse hydrolysable tannins contained in C.longepaniculatum leaves conversion into gallic acid,which showed the strong catalytic activity and high reuse capacity.The aim of the present study was to make full ultilization of C.longepaniculatum leaves resources.Essential oil and procyanidins were obtained from C.longepaniculatum leaves and their bioactivities were also evaluated.Additionally,sulfonated carbon was also obtained.This research truly realizes the high efficient utilization of C.longepaniculatum resources,provides the important data and theoretical basis for the comprehensive utilization of C.longepaniculatum leaves resources. |
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