Physical and Chemical Characterization of Polysaccharides from Dendrobium officinale Kimura Et Migo Leaf and Its Antioxidant Activity
Objective:To provide experiment basis for the development and utilization of Dendrobium officinale leaf resources.Polysaccharides from leaf of Dendrobium officinale Kimura et Migo(LDOP)were prepared.Furthermore,the basic composition,physicochemical properties,and antioxidant activity in vitro of polysaccharide extracts were preliminarily explored.Method:Using Dendrobium officinale Kimura et Migo leaves as raw materials,polysaccharides were prepared by water extraction and alcohol precipitation process combined with macro-porous resin for decolorization and deproteinization.The chemical composition was analyzed,and its molecular weight and monosaccharide composition were tested by chromatography.The rheological properties and antioxidant activity were preliminarily explored in vitro.Result:According to the composition analysis,it was found that the total sugar content of LDOP was 49.40％,the amount of uronic acid,protein,moisture,and ash were 9.60％,0.18％,12.70％,20.70％,respectively.And the results showed that the LDOP were the polysaccharides with high ash and low uronic acid;Monosaccharide composition study showed that the polysaccharide was mainly composed of mannose,glucose,and galactose,with a small amount of arabinose and galacturonic acid.The molar ratio was:mannose∶glucose∶galactose∶arabinose∶galacturonic acid=0.597∶0.176∶0.149∶0.028∶0.049;Rheological studies had shown that the solution of LDOP belong to a non-Newtonian fluid,and exhibit shear thinning phenomenon;The antioxidant test results indicated that the LDOP had potential antioxidant capacity,especially good scavenging ability against hydroxyl radicals.When the concentration was 2 mg/mL,the scavenging rate was up to 81.8％.Conclusion:The polysaccharide resources of Dendrobium officinale Kimura et Migo leaves are abundant and have good antioxidant activity,which is worth further research and development.
leaf polysaccharides of Dendrobium officinale Kimura et Migophysical and chemical characterizationrheological propertiesantioxidant
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