Extraction, optimization, and biological activities of a low molecular weight polysaccharide from Platycodon grandiflorus

Conducting the researches on extraction, optimization, and biological activities of polysaccharides are of great meaning to the development of Platycodon grandiflorus (Jacq.) A. DC. resources. In the present study, the optimum extraction conditions of a low molecular weight polysaccharide (1.9 kDa) from Platycodon grandiflorus (LMw-PGP) were obtained by response surface methodology (RSM), which were ratio of water to raw material 21 mL/g, extraction temperature 80 °C, extraction time 4 h and extraction times 2. Under the optima schemes, the experimental yield of LMw-PGP was 12.15 ± 0.16 % (n = 3). Chemical constituent analysis suggested that the contents of total carbohydrate, protein and uronic acid in LMw-PGP were 94.88 %, 1.27 % and 1.45 %, respectively. Results of MTT assay and cell morphology indicated that LMw-PGP could inhibit the proliferation of SPC-A-1 cells. Additionally, the antioxidant results demonstrated that LMw-PGP had attractive antioxidant capacities, especially the scavenging activity on DPPH radical. Overall, these findings provide a theoretical basis for the potential application of LMw-PGP.