Characterization, antioxidant, and anticancer activities of a neutral polysaccharide from Duchesnea indica (Andr.) Focke

A neutral polysaccharide (DIP‐1) from Duchesnea indica (Andr.) Focke was obtained by hot water extraction, ethanol precipitation and chromatographic separation (DEAE‐52 cellulose anion‐exchange column and Sephadex G‐100 gel column). The physicochemical properties of DIP‐1 were elucidated by gel permeation chromatography, monosaccharide composition, Fourier transform infrared spectrometry, UV–visible spectrophotometry, scanning electron microscope and Congo red test. The results indicated that DIP‐1 was consisted of mannose, glucosamine, glucose, galactose and arabinose in a ratio of 1.00:0.42:18.36:14.17:0.81, and its molecular weight was 218.3 kDa. Meanwhile, DIP‐1 presented a straight hexahedron structure, but no triple‐helical conformation. In antioxidant activity tests, DIP‐1 exhibited powerful scavenging activities on hydroxyl, DPPH, ABTS radicals and reducing power in a dose‐dependent manner. Especially, DIP‐1 demonstrated high inhibitory activities against SKOV‐3 and Hep‐G2 cells in vitro, with IC₅₀ values of 1.42 and 1.23 mg/ml, respectively. PRACTICAL APPLICATIONS: D. indica has been used for a long time as a Chinese medicine for therapy of many diseases, including cancer, inflammation, leprosy, fever, bleeding and so on. At present, polysaccharides have attracted comprehensive attention because of a large range of pharmacological and biological properties, including antitumor, antidiabetic, antioxidant and immunomodulatory activity. In the present study, we purified and characterized a neutral polysaccharide from D. indica for the first time. Moreover, the neutral polysaccharide exhibits significant antioxidant and antitumor activities. Therefore, the present study laid a foundation for the high‐value application of D. indica polysaccharides in functional food and pharmaceutical industries.