Study On The Extraction And Antioxidant Activity Of Perilla Leaf Polysaccharide

Perilla [Perilla frutescens (L.) Britt.] is an annual herb which belongs to Perillaof Labiatae of Sympetalae of Dicotyledoneae. Along with the unceasingly thoroughresearch on comprehensive utilization of perilla, the special active components andnutritional function of perilla seed, stalk, and leaf are increasingly being recognized.However, the research and development about the active ingredients is still in itsinfancy. Therefore, separation and identification of active ingredients and its effectivecomponents from perilla have become the focus. According to the current research onperilla leaf polysaccharide, the optimum technological conditions of water extraction,microwave-assisted extraction to obtain the perilla leaf polysaccharide were studied.Conditions of decolorizing by activated carbon and resin, deproteinization conditionsby seveage mothed, and DEAE-cellulose column chromatography separation werecarried out. In addition, the antioxidant activities of perilla leaf polysaccharide wereinvestigated. This research enhanced the research of effective component in perillaresources, offered the theory and technology foundation for application of perilla leafpolysaccharide, and riched the development and research of the plant polysaccharides.1. The effect of solid-liquid ratio, extraction temperature and extraction time tothe extraction rate of perilla leaf polysaccharide were studied, and the optimumtechnological parameters were obtained by orthogonal test. The result showed thatwhen the solid-liquid ratio was1∶30, extraction temperature was80℃, extractiontime was6h, the extraction rate of perilla leaf polysaccharide could reach at2.21%.The optimum technological parameters of perilla leaf polysaccharide extractingby microwave technique were studied. The result showed that loadage, microwavepower and microwave time were significantly affected the extraction of perilla leafpolysaccharide. The optimum technological parameters of microwave extractiontechnique to the perilla leaf polysaccharide were load10mL, microwave time30s,microwave power800W. The extraction rate of perilla polysaccharide was3.99%.The different extraction effects of perilla leaf polysaccharide by using water extraction and microwave-assisted technique were compared. The result showed thatthere was higher extraction rate and shorter extraction time by usingmicrowave-assisted technique to perilla leaf polysaccharide. However, the use ofdisposable equipment would cause a higher cosr. Therefore, producers would choosethe extraction technique based on the actual situation.2. Conditions of perilla leaf polysaccharide decoloration through active charcoaland resin were studied. Based on the single-factor experiments, afour-factor-three-level experiment design was developed by box-behnken centralcomposite design method, and the process of perilla leaf polysaccharide decolorationthrough active charcoal was optimized by using response surface methodology. Thebest result was obtained when activated carbon dosage was0.58%, pH6.0,decolorization temperature was50℃and decolorization time was15min, thedecolorizing rate reached99.99%and the loss of polysaccharide was5.05%.Process of decoloration through resin was optimized by using orthogonal test. Thebest result was obtained when resin dosage was5.0%, pH6.0, decolorizationtemperature was80℃and decolorization time was60min, the decolorizing ratereached96.1%and the loss of polysaccharide was15.6%.3. The technology and conditions of removing protein from perilla leafpolysaccharide using Seveage method were developed. The result showed that thebest operation conditions were that, chloroform and1-butanol ratio of4, sample liquidand Sevage liquid ratio of1, protein removal time of20minutes and protein removalcycle numbers of2, which lead73.6%of deproteinization rate and17.3%of loss ratio.The extracting solution, the destaining solution, the deproteinizing solution and thedeproteinizing after destaining solution could be separated by DEAE-cellulosecolumn chromatography, and gradiantly eluted with distilled water,0.2,0.4,0.6,0.8,1.0mol/L NaCl eluant to get six components named PLPⅠ, PLPⅡ, PLP Ⅲ, PLPⅣ,PLP Ⅴ, PLPⅥ.4. The antioxidant activity of polysaccharide from perilla leaf was investigated.The antioxidant activities of the extracting solution, the destaining solution, thedeproteinizing solution, the deproteinizing after destaining solution, PLP Ⅰ, PLP Ⅱ, PLP Ⅲ, PLPⅣ, PLPⅤ, PLP Ⅵwere evaluated by determining theirs scavenginghydroxyl radical, superoixide anio radical, DPPH, ABTS free radical, nitrite ion,theirs chelating capability of ferric ion, theirs reducing power. The result showed thatthe perilla leaf polysacchriade has good antioxidant activity.