Effects of Different Temperatures on the Chemical Structure and Antitumor Activities of Polysaccharides from Cordyceps militaris.

Eliyas Nurmamat,Hongxing Xiao,Yan Zhang,Ziwei Jiao

doi:10.3390/polym10040430

Abstract

The effects of different extraction temperatures (4 and 80 °C) on the physicochemical properties and antitumor activity of water soluble polysaccharides (CMPs-4 and CMPs-80) from Cordyceps militaris (C. militaris) were evaluated in this study. The results of gas chromatography (GC) and high-performance gel permeation chromatography (HPGPC) showed that a higher extraction temperature could degrade the polysaccharides with 188 kDa, mainly composed of glucose, and increase the dissolution rate of polysaccharides about 308 kDa, mainly consisting of rhamnose and galactose. In addition, the CMPs displayed the same sugar ring and category of glycosidic linkage based on Fourier-transform infrared spectroscopy (FTIR) analysis, however, their invisible structural difference occurred in the specific rotation and conformational characteristics according to the results of specific optical rotation measurement and Congo red test. In vitro antitumor experiments indicated that CMPs-4 possessed stronger inhibitory effects on human esophagus cancer Eca-109 cells by inducing cell apoptosis more than CMPs-80 did. These findings demonstrated that the polysaccharides extracted with cold water (4 °C) could be applied as a novel alternative chemotherapeutic agent or dietary supplement with its underlying antitumor property.

Highlights

C. militaris, an entomogenous fungus belonging to the class Ascomycetes, has been widely used as a folk tonic food and therapeutic drug for various diseases in East Asia [1]
The results showed that C. militaris polysaccharides (CMPs)-4 and CMPs-80 had similar monosaccharide constituents and a higher proportion of glucose in CMPs-4, while the opposite trend was found in the proportions of rhamnose and galactose, indicating that a higher extraction temperature could degrade the polysaccharide mainly composed of glucose and increase the dissolution rate of polysaccharides consisting of rhamnose and galactose
188 kDa with a percentage area (53.23%). These results indicated that higher extraction temperature could degrade the polysaccharide mainly composed of glucose and increase the dissolution rate of polysaccharides consisting of rhamnose and galactose

Summary

Introduction

C. militaris, an entomogenous fungus belonging to the class Ascomycetes, has been widely used as a folk tonic food and therapeutic drug for various diseases in East Asia [1]. Modern research has shown that polysaccharides from C. militaris possess multiple biological properties, such as antioxidant [5,6,7], antitumor [8,9], immunoregulatory [10,11,12], anti-hyperlipidemic [13], anti-inflammatory activities [14], etc. Previous research has shown that different extraction methods influence the structures and pharmacological activities of polysaccharides [17]. Zhu et al compared the influence of various extraction methods on the chemical structure and antitumor activity of Cordyceps gunnii mycelia polysaccharides, and their remarkable differences were observed in their antitumor effects and physicochemical properties, such as scanning electron microscopy, intrinsic viscosity, and specific rotation [18]. Zhao et al reported that a higher extraction temperature and longer extraction time could cause the hydrolysis of polysaccharides, and further lead to the reduction of polysaccharide yield and the variation of microstructure [20]

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Results

Discussion

Conclusion