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

Young-Ran Song,Chun-Ji Han,Hee-Do Hong,Chang-Won Cho,Eun-Ju Shin,Su-Kyung Sung

doi:10.3390/ijms19092839

Young-Ran Song, Chun-Ji Han + Show 4 more

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https://doi.org/10.3390/ijms19092839

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Abstract

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.

Highlights

Polysaccharides are important biological macromolecules and have attracted considerable attention due to their biocompatibility, low toxicity, unique physical properties, and specific therapeutic properties [1]
Three polysaccharide fractions (ASEP-A, assisted polysaccharide (ASEP)-C, and ASEP-P) were obtained from Aster scaber using the enzyme-assisted method and the following three enzymes: α-amylase, cellulase, and pectinase, respectively, while a polysaccharide fraction (ASWP) obtained with hot water extraction was used for comparison
Our results demonstrated that ASWP, ASEP-A, ASEP-C, and ASEP-P showed the typical absorption peaks of polysaccharides, having a similar backbone and chemical groups, but that sugar compositions of Aster scaber polysaccharides can be affected by different extraction methods

Summary

Introduction

Polysaccharides are important biological macromolecules and have attracted considerable attention due to their biocompatibility, low toxicity, unique physical properties, and specific therapeutic properties [1]. Doellingeria scabra Thunb.), an edible perennial plant of the family Asteraceae, is widely cultivated in Eurasia, including China, Japan, and Korea [7]. Aster scaber has been shown to possess various pharmacological properties such as antioxidant, anticancer, antiviral, antihepatotoxic, neuroprotective, and immunomodulatory activities [8,9,10,11]. These effects have been attributed to the low-molecular-weight phytochemicals present in the plant, including triterpene glycosides, monoterpenes, saponins, polyphenolics, and volatile compounds [7,11]. We reported that the polysaccharide fraction isolated from Aster scaber using hot water extraction enhanced the secretion of nitric oxide (NO) and cytokines such as interleukin (IL)-6, and tumor necrosis factor (TNF)-α in macrophages, and demonstrated anti-complement activity [13]

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