Physicochemical properties of polysaccharides from Dendrobium officinale by fractional precipitation and their preliminary antioxidant and anti-HepG2 cells activities in vitro

Abstract

BackgroundDendrobium officinale as a precious traditional Chinese herb is widely used in medicines and health supplements. Thus the extraction, purification and biological activities of polysaccharides from the stem of Dendrobium officinale have significant meaning on theory and application value.MethodsThe crude Dendrobium officinale polysaccharide (DOP) was obtained by hot water extraction- ethanol precipitation method, and four new polysaccharide fractions (DOP-40, DOP-50, DOP-60, and DOP-70) were further obtained from the crude DOP by fractional precipitation with ethanol method, then four fractions were further purified by Toyopearl-H65F gel resin. The molecular weight and monosaccharide composition of four purified fractions were determined by high performance anion exchange chromatography and high performance liquid chromatography. The antioxidant activities of them were evaluated by the reducing power assay, and the superoxide anion, 2,2-diphenyl-1-picrylhydrazyl (DPPH), and hydroxyl free radicals scavenging assays, respectively. Finally, the anticancer activities of them were investigated via the MTT assay and the western blot analysis using HepG2 cells.ResultsAmong these four purified fractions were mainly composed of d-mannose and d-glucose with different molar ratios, and their average molecular weights were 999, 657, 243 and 50.3 kDa, respectively. What’s more, DOP-70 always exhibited the strongest antioxidant and anticancer activities, while DOP-40 and DOP-60 showed very close antioxidant and anticancer activities which were better than that of DOP-50. The western blotting analysis also showed that DOP-40, DOP-60, and DOP-70 induced apoptosis in HepG2 human liver cancer cells through the Bcl-2 and Bax-dependent pathway.ConclusionsFractional precipitation with ethanol could successfully apply to extract four new polysaccharide fractions from Dendrobium officinale stems, and the polysaccharide fractions possessed efficient antioxidant and anticancer activities, especially DOP-70.

Current advances of Dendrobium officinale polysaccharides in dermatology: a literature review

“…Accumulating evidence showed that D. officinale polysaccharides exhibited valuable high free radicals scavenging activity (Luo et al 2016;Xing et al 2018). In a recent report, a water-soluble polysaccharide obtained from D. officinale has been proved to possess excellent scavenging activity of hydroxyl radical and 1,1diphenyl-2-picrylhydrazyl (DPPH) (Luo et al 2016).…”

“…In a recent report, a water-soluble polysaccharide obtained from D. officinale has been proved to possess excellent scavenging activity of hydroxyl radical and 1,1diphenyl-2-picrylhydrazyl (DPPH) (Luo et al 2016). Xing et al (2018) adopted the ethanol extract method to obtain four purified fractions of DOP (DOP-40, DOP-50, DOP-60 and DOP-70) and found that DOP-40, DOP-60 and DOP-70 exhibited high scavenging activity of O 2 -, DPPH and hydroxyl radicals. Among them, DOP-70 demonstrated the strongest antioxidant ability.…”

“… 2016 ; Xing et al. 2018 ). In a recent report, a water-soluble polysaccharide obtained from D. officinale has been proved to possess excellent scavenging activity of hydroxyl radical and 1,1-diphenyl-2-picrylhydrazyl (DPPH) (Luo et al.…”

“…Xing et al. ( 2018 ) adopted the ethanol extract method to obtain four purified fractions of DOP (DOP-40, DOP-50, DOP-60 and DOP-70) and found that DOP-40, DOP-60 and DOP-70 exhibited high scavenging activity of O 2 - , DPPH and hydroxyl radicals. Among them, DOP-70 demonstrated the strongest antioxidant ability.…”

Genomic Characterization and Expression Analysis of Basic Helix-Loop-Helix (bHLH) Family Genes in Traditional Chinese Herb Dendrobium officinale

“…Among them, polysaccharides, bibenzyls, alkaloids, and flavones have been confirmed as the major and bioactive ingredients [ 3 , 4 ]. The abundance of polysaccharides in its stems and the specific alkaloids make D. officinale have anticancer [ 1 ], anti-oxidant [ 5 ], and anti-inflammatory effects [ 1 , 6 ] as well as support immune modulation [ 7 , 8 ], hepatop protection, and hypoglycemia [ 8 , 9 ]. Due to its multiple health benefits, demand for high-quality D. officinale is increasing across medicine, food, and skin care.…”