The Isolation, Purification, Structure And Antioxidant Activity Of Polysaccharides From Prunella Vulgaris Linn And Tangerine Peel

This study focuses on the isolation, purification, structure characterization and antioxidant activity of the polysaccharides in Prunella vulgaris Linn and Tangerine Peel.The chief results are showed as follows:(1)An efficient complex enzyme extraction(CEE) technology was developed and optimized to extract polysaccharides from Prunella vulgaris Linn. The optimal extraction conditions were as follows: cellulase 0.4%, pectinase 0.8%, papain 0.8%,extraction temperature 61℃, pH 6.2. Under these conditions, the experimental yield was 11.95 ± 0.31%(n=3).The optimal extraction conditions for the microwave-assisted extraction of polysaccharide from tangerine peel were as follows: microwave power704 W, extraction temperature 52.2 ℃, and extraction time 41.8 min. Under these conditions, the experimental yield was19.86 ± 0.23%(n=3).(2)With 40%, 60% and 80% alcohol solution were used to precipitatre polysaccharides. Then decolorized and isolated with DEAE-52 anion exchange column and Sephadex G-75 and G-150 gel column chromatography to obtain PLs-3-1 and TPPs-2-1.(3)Through the analysis of HPGPC. The MW of PLs-3-1 and TPPs-2-1 were8.36×105Da and 1.78×104Da. PLs-3-1 consisted of Rha, Ara, Xyl, Man, Gal and Glc in the molarratio of 1.58: 34.5: 56.31: 1.72: 4.28: 2.05; TPPs-2-1 was composed mainly of GalA(42.47%), Ara(13.8%), Gal(11%), Rha(6.9%), Glc(3.48%), GlcA(18.2%) and Man(4.15%). PLs-3-1 and TPPs-2-1 had typical IR spectra characteristic of polysaccharides as shown by FT-IR. Hydrogen spectrum and carbon spectrum characteristics of polysaccharides by 1H NMR and 13 C NMR.(4)Antioxidant activities were investigated on the basis of FRAP, ?OH, DPPH? and O2-? scavenging assay. The ?OH scavenging rate was 81.62%, the DPPH? scavenging rate was 83.6% at the concentration of 2.0 mg/mL by polysaccharide from Prunella Vulgaris Linn of PLs-3-1. The same concentration by polysaccharide from TPPs-2-1,the ?OH scavenging rate was 64.7%, the DPPH? scavenging rate was 84.5%. TPPs-2-1and PLs-3-1 both had a high FRAP value, a strong radical scavenging activity against? OH and DPPH·, but a weak scavenging activity against O2- ?. The activity of two polysaccharides was affected by its monosaccharide composition, molecular weight and extraction methods. These finding indicated that PLs-3-1 and TPPs-2-1 have the potential to be antioxidant that could be further developed in the functional foods and pharmaceutical industries.