Extraction, preparation and an assessment of the activity of carboxymethyl polysaccharide from Panax japonicus

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.