Antioxidantion and composition analysis of purified polygonatum sibiricum polyphenols using macroporous resin

Polygonatum sibiricum becomes generally used as a sort of traditional medicinal herbs for thousands of years in China. This herbs contains a large number of active ingredients, such as polysaccharides, flavonoids, polyphenols, to cure many physiological functions including antioxidant, anti-fatigue, hypoglycemic, hypolipidemic, anti-cancer etc. This present work focused on the purification processing of the raw Polygonatum polyphenols by using the specific macroporous resin. A sort of resin, named AB-8, was chosen as the ideal adsorbent due to the best adsorption and the desorption rate for Polygonatum polyphenols, after the comparison test for the adsorption-desorption characteristics of four different types of resins (AB-8, NKA-9, SP-825 and XAD-2) for crude Polygonatum polyphenols. In the static/dynamic adsorption and desorption experiments, the sample concentration, flow velocity of samples, ethanol concentration and flow velocity of desorption showed great influence on the macroporous resin in the process of separating and purifying the Polygonatum polyphenols. The ideal purification parameters for the resin of AB-8 were as follows, at room temperature, the concentration of crude polyphenol was 0.80 mg/mL with the flow velocity of 0.8 mL/min, and 70% ethanol was used as the eluent solvent with the elution flow rate of 1 mL/min. The Folin-phenol reagent method was adopted to determine the total phenol content during the purification. The results showed that the purity of Polygonatum polyphenols after purification by AB-8 resin increased by 3.37 times than the crude polyphenol extract indicating that AB-8 resin has great adsorption and enrichment effect for Polygonatum polyphenols. The total reduction capacity, scavenging capacity of DPPH? and ABTS+? were measured to investigate the antioxidant capacity of crude and purified Polygonatum polyphenols. The obtained results showed that Polygonatum polyphenols possessed good antioxidant capacity with the dose-effect relationship. IC50 values of total reduction capacity of Polygonatum polyphenols before and after purification were (27.48+1.93) ?g/mL, (19.01+1.48) ?g/mL, IC50 values of DPPH? scavenging activities were (5.21+0.48) ?g/mL, (4.00+0.26) ?g/mL, and IC50 values of ABTS+? scavenging activities were (4.89+0.82) ?g/mL and(4.21±0.53) ?g/mL, respectively. Obviously, the antioxidant activity of Polygonatum polyphenols was significantly enhanced after purification. The infrared spectrum and HPLC were also used to analyze the structure characteristics and compositions of the purified products. The characteristic peaks of some polyphenols and flavones can be detected, where Polygonatum polyphenols mainly contains green source acid, ferulic acid, rutin and ursolic acid. The present study can provide a scientific basis for the structure-activity analysis of Polygonatum polyphenols and their promising utilization in the functional food, medicine and cosmetics.