| Plant phenolics are secondary metabolites of plants,and they are widely distributed in nature.Plant phenolics have significant bioactivity in anti-oxidation,anti-tumor,anti-bacterial and prevention of cardiovascular diseases.Therefore,researchers have maintained high interests in plant phenolics.Sacha Inchi(SI)is native in Amazon low land in Peru.In 2006,Xishuangbanna tropical botanical garden of Chinese academy of science introduced SI cultivation from Peru successfully,and it has been gradually planted in many places in China such as Yunnan Province.SI oil has been authenticated as a kind of new resources food since2013.According to the calculations,the annual production of SI shells in China and its neighboring cooperative countries is about 12,000 tons.Some literatures show that there are some phenolic compounds in SI shells.However,there are few specific studies on phenolic compounds in SI shells in the current research.In this thesis,the extraction and the purification of phenolic compounds in SI shells were carried out,and the structures of phenolic compounds were preliminarily identified.In addition,the ability of scavenging free radicals of phenolic compounds was also detected.All of those provided a theoretical basis for the comprehensive utilization of SI shells.At the first,ultrasonic assisted extraction technological conditions of phenolic compounds in SI shells were investigated.The effects of the solvent types,volume fraction,ultrasonic temperature,ultrasonic time,ultrasonic power and solid-liquid ratio on the extraction rate were studied.The technological conditions for the ultrasound-assisted extraction of phenolic compounds in SI shells were determined as follows:the extraction solvent was 70%(volume ratio)ethanol,the ultrasonic temperature was 50°C,the ultrasonic time was 40 minutes,and the ultrasonic power was 350 W,the solid-liquid ratio is 1:20(g:mL).Under this technological condition,the extraction rate of phenolic compounds in SI shells was 54.1 mg/g.Secondly,the macroporous resin was used to purify the phenolic compounds in SI shells.The NKA-9 type macroporous resin had relatively better adsorption and desorption rates for the phenolic compounds in SI shells among the 6 types of macroporous resin that chosen.The size of?2.5 cm×30 cm glass column was used as purification column and NKA-9 type resin was used as fillers to do the dynamic adsorption and desorption with the phenolic water solution.The conditions for the purification of phenolic compounds in SI shells were determined through single factor experiments as follows:the sample concentration was 10mg/mL,and the sample flow rate was 2 mL/min.After the end of saturated adsorption,2 BV(bed volume)of purified water was used to wash the soluble sugar,protein and other impurities.And then eluted with 70%(volume ratio)ethanol solution,the elution rate was 1.0mL/min and the amount of eluent was 2.5 BV(bed volume).After purification,the purity of the phenolic compounds was 73.8%,which was increased by 1.2 times compared to 33.2%of purity of the crude extract.Then,silica gel plate(GF254)was used to separate the phenolic compounds in SI shells.The phenolic compounds were divided into 4 bands.Then UPLC-PDA-MS was used to analyze the chemicals in every band after enrichment.The structures of phenolic compounds were identified preliminarily:there are vanillic acid hexoside,1,2-disinapoyl-feruloyl-gentiobiose(tentative),cyanidin 3-(6”-feruloylsophoroside)-5-glucoside,malvidin 3-glucoside and malvidin 3-glucoside dimer in the band 1;there are vanillic acid hexoside,vanillic acid hexoside trimer and vanillic acid hexoside dimer in band 2;there are p-hydroxybenzoic acid,hydroxybenzoic acid hexoside,p-coumaroyl hexose and p-coumaric acid tetramer in band 3;there are p-hydroxybenzoic acid and p-coumaric acid in band 4.Finally,the abilities of scavenging DPPH,ABTS and OH radicals of the substances in the 4 bands were detected,and V_C were regarded as control.It turned out that the substances in band NO.1(the band with vanillic acid hexoside,1,2-disinapoyl-feruloyl-gentiobiose(tentative),cyanidin 3-(6”-feruloylsophoroside)-5-glucoside,malvidin 3-glucoside and malvidin 3-glucoside dimer)were more potent than V_C in scavenging DPPH,ABTS,and OH free radicals,and they had the strongest free radical scavenging ability among 4 bands.The substances in band NO.2(the band with vanillic acid hexoside,vanillic acid hexoside trimer and vanillic acid hexoside dimer)had better ability of scavenging DPPH free radicals than V_C,but the abilities of scavenging ABTS and·OH free radicals were weaker than V_C.Both the substances in band NO.3(the band with p-hydroxybenzoic acid,hydroxybenzoic acid hexoside,p-coumaroyl hexose and p-coumaric acid tetramer)and the substances in band NO.4(the band with p-hydroxybenzoic acid and p-coumaric acid)had very weak abilities of scavenging free radicals,and abilities were much lower than V_C.Besides,the substances in band NO.4 had little weaker ability of scavenging free radicals than the substances in band NO.3. |
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