The Effect of Pectinase-Assisted Extraction on the Physicochemical and Biological Properties of Polysaccharides from Aster scaber.

The edible and medicinal perennial herb Aster scaber is known to have anticancer, antioxidant, and immunomodulatory properties. However, the biological effects of its polysaccharides are not well understood. Here, we aimed to extract novel polysaccharides with enhanced biological properties from Aster scaber using enzyme-assisted methods. Amylase, cellulase, and pectinase were used to extract enzyme-assisted polysaccharide (ASEP)-A, ASEP-C, and ASEP-P, respectively. The yields, physicochemical properties, and immunostimulatory activities of the polysaccharides were investigated and compared with those of hot water extracted polysaccharide (ASWP). The highest yield (3.8%) was achieved for ASEP-P extracted using pectinase digestion. Fourier-transform infrared spectroscopy (FT-IR) and chemical composition analysis revealed that ASWP and three ASEPs were typical acidic heteropolysaccharides, mainly comprising rhamnose, arabinose, galactose, glucose, and galacturonic acid. Immunostimulatory activity assays on RAW264.7 macrophages showed ASEP-P to have the greatest immunostimulatory potential in terms of nitric oxide (NO) and cytokine productions and phagocytic activity. ASEP-P administration improved immune-enhancing effects in normal mice by improving the spleen index and splenic lymphocyte proliferation, and in immunosuppressed mice by modulating lymphocyte proliferation, natural killer (NK) cell activity, and leukocyte counts. The ASEP-P derived from pectinase hydrolysate of Aster scaber demonstrated efficacious immunostimulatory properties and has potential applications as an immune stimulator.

Enzyme-assisted extraction, chemical characteristics, and immunostimulatory activity of polysaccharides from Korean ginseng (Panax ginseng Meyer).

In this study, enzyme-assisted extraction was used to isolate functional polysaccharides from Korean ginseng (Panax ginseng Meyer) and the physicochemical and biological properties of the extracted polysaccharides were investigated, comparing with those from traditional hot-water extraction (FGWP). In macrophages, their effects on cytokines production could be ordered as FGEP-CA ≥ FGEP-A > FGEP-C > FGWP, suggesting that FGEP-CA (combined cellulase- and α-amylase-extracted polysaccharide) is a potent immunostimulator. In addition, enzymatic digestion led to differences in the monosaccharide profile of the extract. FGWP mainly consisted of rhamnose, arabinose, galactose, galacturonic acid, and glucose in molar percentages of 1.8:10.1:9.2:17.8:60.6, whereas FGEP-CA was 3.2:11.4:16.5:22.3:45.8, respectively, suggesting that enzyme-assisted extraction of ginseng polysaccharides produces a higher proportion of pectin polysaccharides. The HPLC profile of FGEP-CA also showed lower and more heterogeneous molecular weights than FGWP did. In cyclophosphamide-induced immunosuppressed mice, FGEP-CA administration ameliorated decreased spleen and thymus indices (200 mg/kg), lymphocyte proliferation, natural killer cell activity, leukocyte counts, and the serum cytokines, interleukin-2, interleukin-6, and interferon-γ (100 and 200 mg/kg). These results suggest that enzyme-assisted extraction using cellulase and α-amylase is an effective method for the preparation of functional polysaccharides from fresh Korean ginseng, and FGEP-CA could be utilized as a potential immune-stimulatory agent.