Abstract Polysaccharides are a class of biological macromolecules made up of sugar chains with multiple glycosidic bonds. To explore the extracted, purified, carboxymethylated and phosphorylated modified to obtained carboxymethylated polysaccharides (HSPS) and phosphorylated polysaccharides (HSPP), and the HSPS and HSPP were characterized and analyzed, and their antioxidant activity measured. Response surface design was used for the synthesis process of HSPS and HSPP, the structure characterization and antioxidant activities of HSPS and HSPP were evaluated. The results showed that the Mw and Mn of HSP were 14.66 kDa and 8.39 kDa, respectively. The monosaccharides were mainly galactose, glucose, xylose, and arabinose in a molar ratio of 37.68%: 24.43%: 13.63%: 9.18%. The optimal synthesis conditions for HSPS were as follows: reaction time of 2.01 h, reaction temperature of 44.61°C and the amount of monochloroacetic acid necessary was 1.18 g. The optimal synthesis conditions for HSPP were: reaction time of 4.28 h, reaction temperature of 80.78°C, and reaction pH of 8.98. HSPS and HSPP have scavenging effects on ABTS, super oxideanion and hydroxyl radicals. The HSPS and HSPP were characterized and analyzed, and their antioxidant activity measured.

Abstract A response surface method (RSM) was employed to optimize polysaccharide extraction from Panax japonicus (PJPS). Also, carboxymethyl substitution of PJPS (CM-PJPS) was studied using a response surface methodology. A three-variable Box–Behnken design (BBD) methodology was applied. RSM analyses revealed that conditions that maximized polysaccharide yield were as follows: a liquid-to-material ratio 22:1, an extraction temperature of 83.99 °C and an extraction duration of 2.32 h. Under optimum extraction conditions, the average absorbance value of PJPS was 0.6001, and the purity of PJPS was 98.2%. A quadratic regression model for CM-PJPS was obtained via BBD. The optimum extraction conditions for the process were determined to include a 1.38 h reaction time, 1.24 g monochloroacetic acid (MCA) and a reaction temperature of 52.85 °C. Under optimum extraction conditions, the average degree of CM-PJPS substitution was 0.9733. The structure of the PJPS was examined by means of Fourier transform infrared spectroscopy (FTIR). CM-PJPS exhibited the strongest anti-oxidant activity in vitro. In addition, CM-PJPS inhibited Skov3 and A2780 cancer cell proliferation. Our data revealed that CM-PJPS is a promising natural antioxidant with potential value as a food supplement and for treatment of cancer.

Abstract In this study, we extracted lotus root polysaccharide (LRP) and synthesised phosphorylated lotus root polysaccharide (PLP) using response surface methodology (RSM). RSM analyses revealed that the optimal conditions for PLP synthesis were a reaction duration of 7 h, temperature of 70 °C and pH of 11.38. Under these conditions, the predicted degree of substitution (DS%) was determined to be 9.96%. The structure of the LRP1 was examined by ultraviolet (UV) spectroscopy scan, Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR) (1H and 13C). The monosaccharide composition of LRP1 was determined to be mannose (0.12%), ribose(0.18%), glucuronic acid(0.60%), galacturonic acid(0.09%), glucose(98.79%) and galactose(0.21%). The number average molecular weight (Mn) and the weight average molecular weight (Mw) of LRP1 were 10236 and 251783 g/mol. LRP1 exhibited high antioxidant activities in scavenging ABTS radicals, Superoxide anion radicals and Metal ion scavenging activity. PLP exhibited strong antioxidant activity in vitro. In addition, PLP inhibited Skov3 cancer cell proliferation and induced reactive oxygen species (ROS) production. Our data revealed that PLP is a promising natural antioxidant with potential value as a food supplement and for the treatment of cancer.

Abstract In this study, lotus root polysaccharide was taken as raw material. The preparation technology of its polysaccharide selenium was established by response surface design, and its antioxidant activity in vitro was studied. Selenium content was taken as the detection index, and the effects of reaction time, the ratio of sodium selenite to the polysaccharide, and the volume fraction of nitric acid on selenium content were investigated. Through the response surface method, the optimal synthesis conditions of lotus root polysaccharide selenium were obtained as follows: reaction time of 5.36h, the ratio of sodium selenite and lotus root polysaccharide is 0.78, the volume fraction of nitric acid 0.47%, the selenium content of lotus root polysaccharide selenium 0.1106%. Selenium, a polysaccharide from lotus root, had a scavenging effect on ABTS radical and superoxide ion, and the maximum scavenging rate was 52.17% and 85.23%, respectively. Aa shows that the synthesized lotus root polysaccharide selenium can be used as an antioxidant or functional food.

Abstract In this study, we extracted lotus root polysaccharide (LRP) and synthesized carboxymethylated lotus root polysaccharide (CM-LRP) using response surface methodology (RSM). The monosaccharide component of LRP was analyzed by pre-column derivatization high performance liquid chromatography (PCD-HPLC). The polysaccharide was characterized by ultraviolet (UV) spectroscopy scan, Fourier transform infrared spectroscopy (FTIR), circular dichroism spectrometer (CD), and scanning electron microscopy (SEM). It was found that the main monosaccharide component of LRP was glucose, accounting for more than 98% of the total polysaccharide component. RSM analyses revealed that the optimal conditions for CM-LRP synthesis were a reaction duration of 2.22 h, the chloroacetic acid dosage is 2.02 g, and a temperature of 46.87 °C. Under these conditions, the predicted degree of substitution (DS) was determined to be 0.5101. The superoxide anion, ferrous ion and hydroxyl radical antioxidant system were constructed to study the antioxidant activity of LRP and CMLRP. The activity of CMLRP to remove ferrous ions and hydroxyl radicals were significantly stronger than that of LRP, and it also showed a certain concentration-dependent. LRP has a better scavenging ability than CMLRP in scavenging superoxide anion free radicals. Our data revealed that CM-LRP is a promising natural antioxidant with potential value as a food supplement.