| Zanthoxylum?Zanthoxylum bungeanum maxim?is dungarunga,woody climber or deciduous shrub of the Rutaceae.It is divided into two categories: zanthoxylum schinifolium and pericarpium zanthoxyli bungeani.Besides China,it is also planted in Nepal,Malaysia,Pakistan and Japan,distributed mainly in plains and mountains with an altitude of 1300-1500 meters.Both the fruits and leaves of zanthoxylum contain fatty acid amides,terpenoids,alkaloids,flavonoids and other phenolics,and have anti-inflammatory,insecticidal,anti-fungal and anti-microbial activities.The contained unsaturated fatty amides are the characteristic components of uniquely intensive numb-taste of zanthoxylum.In this paper,the numb-taste components of zanthoxylum were separated through organic solvent extraction method with combination of AB8 macroporous polymeric adsorbent chromatography,and purified for crude extract through preparative HPLC.The detection method had been established,using High Performance Liquid Chromatography to test numb-taste components quantitatively.Additionally,the oxidation resistance of numb-taste components and the application in antioxidant for oil and fat had been studied and determined.The research results are as the following.?1?The separation and purification processes for numb-taste components are as the following:Zanthoxylum bungeanum powder ? Soxhlet organic solvent extraction? solvent?methanol?removal ? AB8 macroporous polymeric adsorbent separation ? methanol elution ?recovery of the 3th,4th and 5th tube elution solution? solvent removal by rotary evaporation ?Low temperature freezing crystallization ?dissolution ? preparative high performance liquid chromatography ?Low temperature freezing crystallization.?2?The best zanthorylum bungeanum oleoresin extraction conditions are confirmed by integrating single factor analysis and orthogonal analysis methods,liquid-to-solid ratio of 1:14,extraction temperature of 55 ? and refluxing time of 3h.Under these conditions,the extraction rate of zanthorylum bungeanum oleoresin is up to 7.69%.?3?The influences of eluent and flow rate to numb-taste components separation effects of AB8 macroporous polymeric adsorbent were studied and discussed,by using UV spectrophotometry.Finally,methanol is selected as the eluent,and the best elution effect can be obtained when the flow rate is controlled within 2.5ml/min.?4?The numb-taste components samples,which are obtained after preparative HPLC separation and purification,are used to establish HPLC test method for numb-taste components contents.When the concentration range is in 012.0?g/mL,standard curve equation is y=0.1992x?R2=0.9995?,and linear relation of standard curve is good.Technical indexes of the method are as the following: recovery rate range is 98.87%100.3%,and the variation coefficient of precision test and stability test is less than 3%.The method is of high accuracy,repeatability and stability.?5?The numb-taste components have obvious scavenging effect for two kinds of free radicals,superoxide anion radical O2·— and 1,1-diphenyl-2-Picrylhydrazyl radicals DPPH?.The scavenging rate increases along with the sample concentration,and it shows certain dose-effect relationship.On antioxidative stability aspect,the antioxidant activity of the numb-taste components decreases significantly under higher temperature.In the acidity range of pH 57,the numb-taste components have high and stable antioxidant activity.It is suitable for antioxidant of neutral to slightly acidic foods.?6?The antioxidant effects are determined when adding the numb-taste components in rapeseed oil.The antioxidant effects of different amount of numb-taste components to oil & fat is evaluated by measuring two evaluation indexes of oil oxidation and rancidity,peroxide value?POV?and acid value?AV?.The results show that the numb-taste components have oxidation inhibition effect for rapeseed oil.The inhibition capability increases along with the increasing of concentration.The effect on hydrolysis rancidity is also similar,i.e.inhibition capability increases along with the increasing of zanthorylum bungeanum oleoresin concentration of numb-taste components. |
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