Dendrobium Officinale Polysaccharide Research Articles

Optimization of the extraction process of polysaccharides from Dendrobium officinale and evaluation of the in vivo immunmodulatory activity

Dendrobium officinale (D. officinale) was regarded as the nutritious food in Asia for the remarkable bioactivities on immunmodulatory. Dendrobium officinale polysaccharide (DOP) served as the main active compound in the herb. Extraction of DOP was investigated and immunmodulatory activities were evaluated. The optimal extraction process (liquid-to-material ratio of 24.6:1, extraction time of 2.1 hr, and temperature of 67.4 °C) was obtained by single-factor analysis and response surface optimization. Under this condition, DOP reached the extraction yield of 92.42%. Furthermore, DOP can promote the proliferation of splenic lymphocytes of immunodeficient mice and enhance the phagocytic capability of peritoneal macrophages. The contents of IL-6 and TNF-α in serum and splenocyte supernatants were significantly upregulated. Similarly, the contents of immune globulins (IgM and IgG) and hemolysis in serum was increased, as well as the antioxidant capabilities of thymus and serum. Therefore, this work gave an effective extraction method for DOP, and elucidated the immunmodulatory mechanisms of DOP at the level of the animal. Practical applications Dendrobium officinale polysaccharide (DOP) is active compounds in Dendrobium officinale (D. officinale), which was widely used as nutritious food in Asia for its remarkable bioactivities such as the curative effect on chronic atrophic gastritis and hypertension and diabetes, tumor-suppression, and anti-aging effects. In the current study, it optimized the extraction process to acquire high-quality and stable DOP. Furthermore, it explored the immunoregulatory mechanism of DOP using immunosuppressive mouse model. This work contributed to the further development and utilization of DOP as a novel nutritious food additive component.

The protective effect of Dendrobium officinale polysaccharides on photoaging fibroblasts by scavenging reactive oxygen species and promoting the expression of TGF-β1

The protective effect of Dendrobium officinale polysaccharides on photoaging fibroblasts by scavenging reactive oxygen species and promoting the expression of TGF-β1

Dendrobium officinale polysaccharide attenuates type 2 diabetes mellitus via the regulation of PI3K/Akt-mediated glycogen synthesis and glucose metabolism

This study aimed to explore the therapeutic effects of Dendrobium officinale polysaccharide (DOP), an active ingredient isolated from the water extract of Dendrobium officinale, in streptozotocin (STZ)-induced type 2 diabetic BALB/c mice and its potential mechanisms. Our results showed that DOP had beneficial effects in ameliorating hyperglycemia, insulin resistance and dyslipidemia. Additionally, DOP promoted glycogen synthesis via regulating the expression of glycogen synthase kinase 3 beta (GSK-3β), glycogen synthase (GS) and glucose transporter 4 (GLUT4) in the liver or muscle. Moreover, DOP reduced the blood glucose levels via the regulation of glucose metabolizing enzyme activity including pyruvate kinase (PK), hexokinase (HK) and phosphoenolpyruvate carboxykinase (PEPCK) in the liver. Furthermore, mechanistic studies illustrated that DOP could up-regulate the expression of PI3K/Akt signaling proteins both in vivo and in vitro. Our findings revealed that DOP improves glucose metabolism disorder by promoting glycogen synthesis and regulating the activity of glucose metabolism enzymes.

Inhibitory effect of Dendrobium officinale polysaccharide on human gastric cancer cell xenografts in nude mice

Abstract This study investigated the inhibitory effect of Dendrobium officinale polysaccharide (DOPA) on human gastric cancer cell SGC-7901 xenografts in nude mice. The nude mice with SGC-7901 xenografts were randomly divided into model, 5-fluorouracil (5-Fu), low-dose DOPA, middle-dose DOPA and high-dose DOPA group. The later four groups were intragastrically administrated with 100, 200 and 400 mg·kg–1·day–1 DOPA, 400 mg·kg–1·day–1 5-Fu and normal saline, respectively. After treatment for 20 days, the tumor inhibition rate of in high-dose DOPA group was basically equivalent to 5-Fu group. Compared with 5-Fu, DOPA had no obvious toxic side effect on spleen or thymus indexes, routine blood indexes or liver and kidney functions of nude mice. Compared with model group, the serum tumor necrosis factor-α and interleukin-2 levels in middle- and high-dose DOPA group were significantly increased (P < 0.05), Bax protein expression was significantly increased (P < 0.05), and Bcl-2 protein expression was significantly decreased (P < 0.05). DOPA can inhibit the growth of SGC-7901 cell xenografts in nude mice. The mechanism may be related to its increase of serum TNF-α and IL-2 levels, up-regulation of Bax protein expression and down-regulation of Bcl-2 protein expression.

Protective roles and mechanisms of Dendrobium officinal polysaccharides on secondary liver injury in acute colitis

The purpose of this study was to investigate the protective roles and mechanisms of Dendrobium officinale polysaccharides (DOPS) on secondary liver injury in acute colitis. Firstly, the mice model of secondary liver injury in acute colitis was induced by 4% Dextran sodium sulfate (DSS). Inflammatory cell model was established by LPS-stimulated RAW264.7 cells. Then, the protective roles of DOPS were evaluated by both in vivo and in vitro experiment. The results showed that DOPS attenuated DSS-induced hepatic pathological damage, liver parameters, infiltration of macrophages, cytokines levels, MDA level and increased the antioxidant enzymes activities. In vitro, DOPS markedly inhibited inflammatory cytokines production and increased antioxidant enzymes activities. Finally, its molecular mechanisms were also observed. The results indicated that DOPS could down-regulated TNF-α signaling pathway and activated Nrf-2 signaling pathway in vivo and in vitro. These results suggested that DOPS may be an effective therapeutic reagent to attenuate secondary liver injury in acute colitis.

Protective effect of Dendrobium officinale polysaccharides on H2O2-induced injury in H9c2 cardiomyocytes

The preliminary studies have shown that Dendrobium officinale possessed therapeutic effects on hypertension and atherosclerosis. Studies also reported that Dendrobium officinale polysaccharides showed antioxidant capabilities. However, little is known about its effects on myocardial cells under oxidative stress. The present study was designed to study the protective effect of Dendrobium officinale polysaccharides against H2O2-induced oxidative stress in H9c2 cells. MTT assay was carried out to determine the cell viability of H9c2 cells when pretreated with Dendrobium officinale polysaccharides. Fluorescent microscopy measurements were performed for evaluating the apoptosis in H9c2 cells. Furthermore, effects of Dendrobium officinale polysaccharides on the activities of antioxidative indicators (malondialdehyde, superoxide dismutase), reactive oxygen species (ROS) production and mitochondrial membrane potential (MMP) levels were analyzed. Dendrobium officinale polysaccharides attenuated H2O2-induced cell death, as determined by the MTT assay. Dendrobium officinale polysaccharides decreased malondialdehyde levels, increased superoxide dismutase activities, and inhibited the generation of intracellular ROS. Moreover, pretreatment with Dendrobium officinale polysaccharides also inhibited apoptosis and increased the MMP levels in H9c2 cells. These results suggested the protective effects of Dendrobium officinale polysaccharides against H2O2-induced injury in H9c2 cells. The results also indicated the anti-oxidative capability of Dendrobium officinale polysaccharides.

A polysaccharide of Dendrobium officinale ameliorates H2O2-induced apoptosis in H9c2 cardiomyocytes via PI3K/AKT and MAPK pathways

Dendrobium officinale is one valuable traditional Chinese medicine, which has skyscraping medicinal value. Polysaccharide is the main active ingredient in D. officinale; its antioxidant activity is a hot research topic nowadays. Oxidative stress plays an important role in the pathological progress of a variety of cardiovascular disease, as one of key factors of cardiomyocyte apoptosis. This research adopts a model of H2O2 induction-H9c2 cardiomyocytes apoptosis, aiming to study the effect of Dendrobium officinale Polysaccharide (DOP-GY) for cardiomyocyte apoptosis caused by oxidative stress and its possible mechanism. Our results showed that pretreatment of DOP-GY (low dose: 6.25μg/mL, medium dose: 12.5μg/mL, high dose: 25μg/mL) followed by a 2h incubation with 200μM H2O2 elevated the survival rate, cutted the LDH leakage, reduced lipid peroxidation damage, improved the activity of the endogenous antioxidant enzymes. In addition, the pretreatment of DOP-GY significantly inhibited the production of ROS, declined of the mitochondrial membrane potential, down-regulated pro-apoptosis protein and up-regulated anti-apoptosis protein. The protective effect was correlated with the PI3K/Akt and MAPK signal pathway. Collectively, these observations suggest that DOY-GY has the potential to exert cardioprotective effects against H2O2-induced H9c2 cardiomyocyte apoptosis.

Effects of Dendrobium officinale polysaccharide on adipogenic differentiation of rat bone marrow mesenchymal stem cells

Abstract This study investigated the effect of Dendrobium officinale polysaccharide (DOP) on the adipogenic differentiation of rat bone marrow mesenchymal stem cells (BMSCs). DOP was extracted fresh Dendrobium officinale. Rat BMSCs were prepared, and then were treated with 0 (control), 50, 100, 200, 400, 800 μg/mL DOP, respectively. The cell viability was determined by MTT assay. The adipogenic differentiation was quantitatively analyzed by oil red O staining assay. The mRNA expressions of adipogenic differentiation related gene peroxisome proliferator-activated receptor gamma (PPARG), lipoprotein lipase (LPL) and fatty acid binding protein 4 (FABP4) were detected by RT-PCR. Results showed that, DOP with 0-800 μg/mL concentration had no significant toxicity to BMSCs. 200-800 μg/mL DOP could obviously inhibit the adipogenic differentiation of BMSCs. Compared with control group, the expression levels of PPARG, LPL and FABP4 mRNA 200, 400 and 800 μg/mL DOP groups were significantly decreased (P < 0.05 or P < 0.01). DOP can inhibit the adipogenic differentiation of BMSCs, which may be related with its down-regulation of PPARG, LPL and FABP4 expressions in BMSCs.

Effect of Dendrobium officinale on D-galactose-induced aging mice.

To examine the effect of Dendrobium officinale (DO) on D-galactose-induced aging mice. Aging mice was induced by D-galactose at 0.125 g/kg for 10 weeks through subcutaneous injection except for the negative control group. After 10 days, according to complete random design, the aging modeling mice were randomized into 4 groups: aging control group (10 ML·kg-1·d-1) of distilled water), positive control group (vitamin B6 and ganodema lucidum tablets with a dose of 1 tablet/kg), DO-1 treatment group (DO juice with a dose of 1 g/kg), DO-2 treatment group (DO Polysaccharide with a dose of 0.32 g/kg), 14 mice in each group. All the animals were orally medicated daily for 9 weeks. Cognitive function assessment was performed using the maze test and step-down test. At the end of experiment, the superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and total antioxidant capacity (T-AOC) levels in the serum, the SOD, GSH-Px and nitric oxide (NO) levels in the cerebrum, the SOD and catalase (CAT) levels in the liver, the SOD and NO levels in the heart, and the SOD level in the kidney, were determined using commercial kits. The spleen, liver, heart, cerebrum and kidney were excised for histological study. Compared to aging control group, DO shortened the time of passing through the maze and prolong the step-down latency of aging mice (P <0.05 or P<0.01). DO markedly up-regulated serum levels of SOD, GSH-Px and T-AOC, and restored SOD levels in the heart, liver, kidney and cerebrum to normal status (P<0.05 or P<0.01). DO at the dose of 1 g/kg also signififi cantly improved the degree of spleen lesions (P<0.01). DO had marked anti-aging effect on D-galactose-induced model of aging. The underlying mechanism could be related to modulation on antioxidation system and immune system. The results indicated that DO could potentially be used as natural drugs or functional foods for preventing aging.

Study on Dendrobium officinale O-Acetyl-glucomannan (Dendronan). 7. Improving Effects on Colonic Health of Mice.

This research was aimed to study the effect of Dendrobium officinale polysaccharide (Dendronan) on colonic health. Mice were fed Dendronan at doses of 40, 80, and 160 mg/kg body weight for 0, 10, 20, and 30 days, respectively. Results showed that Dendronan, which has a special structure formed by mannose and glucose, rich in O-acetyl groups, exhibited improving effects on colonic and fecal parameters of Balb/c mice. After Dendronan feeding, the content of short-chain fatty acids (SCFAs), colon length and index, and fecal moisture were increased, whereas colonic pH was decreased and defecation time was shortened. All of these changes were significantly different between polysaccharide-treated groups and the control group (p < 0.05). These findings suggested that an adequate intake of Dendronan is beneficial to the process of fermentation and regulation of colonic microenvironment, thus playing a role in the maintenance of colonic health.

Study on Dendrobium officinale O-acetyl-glucomannan (Dendronan): Part IV. Immunomodulatory activity in vivo

As part of a series of studies on the bioactivities and structures of polysaccharides from Dendrobium officinale, this study investigates the immunomodulatory activities of Dendrobium officinale and its two polysaccharide fractions (crude and purified, respectively) in cyclophosphamide induced mice. All three materials protected the body from immunosuppression in a dose-dependent manner. Biological activities related to immunomodulations investigated included stimulating the proliferation of splenocytes, balancing the ratio of spleen lymphocyte subsets and the secretion of serum cytokines, up-regulating the serum IgM, IgG and haemolysin formation, and accelerating the phagocytotic function of peritoneal macrophage. The degree of modulations were higher in purified Dendrobium officinale polysaccharide than crude polysaccharide, indicating that the purified polysaccharide was one of the key bioactive components in Dendrobium officinale, the main structure of which has been identified as O-acetyl-glucomannan (Dendronan)

Study on Dendrobium officinale O-acetyl-glucomannan (Dendronan®): Part II. Fine structures of O-acetylated residues

Main objective of this study was to investigate the detailed structural information about O-acetylated sugar residues in Dendronan®. A water solution (2%, w/w) of Dendronan® was treated with endo-β-mannanase to produce oligosaccharides rich in O-acetylated sugar residues. The oligosaccharides were partly recovered by ethanol precipitation (70%, w/w). The recovered sample (designated Hydrolyzed Dendrobium officinale Polysaccharide, HDOP) had a yield of 24.7% based on the dry weight of Dendronan® and was highly O-acetylated. A D2O solution of HDOP (6%, w/w) generated strong signals in 1H, 13C, 2D 1H–1H COSY, 2D 1H–1H TOCSY, 2D 1H–1H NOESY, 2D 1H–13C HMQC, and 2D 1H–13C HMBC NMR spectra. Results of NMR analyses showed that the majority of O-acetylated mannoses were mono-substituted with acetyl groups at O-2 or O-3 position. There were small amounts of mannose residues with di-O-acetyl substitution at both O-2 and O-3 positions. Minor levels of mannoses with 6-O-acetyl, 2,6-di-O-acetyl, and 3,6-di-O-acetyl substitutions were also identified. Much information about sugar residue sequence was extracted from 2D 1H–13C HMBC and 2D 1H–1H NOESY spectra. 1JC–H coupling constants of major sugar residues were obtained. Evidences for the existence of branches or O-acetylated glucoses in HDOP were not found. The major structure of Dendronan® is shown as follows:▪

Partial characterization and immunomodulatory activity of polysaccharides from the stem of Dendrobium officinale (Tiepishihu) in vitro

The crude polysaccharide from the stem of Dendrobium officinale (DOP) was obtained by water extraction and ethanol precipitation. Two fractions of DOP, DOP-1 and DOP-2, were fractioned by DEAE cellulose and Sephacryl S-400 gel filtration column chromatography. Their molecular weights and monosaccharide compositions were studied. The immunomodulatory activity of DOP, DOP-1 and DOP-2 was evaluated with in vitro cell models. The results showed that the 533.7kDa DOP-1 and 159.5kDa DOP-2 were mainly composed of mannose and glucose. Both DOP and its purified fractions significantly (P<0.05) promoted splenocyte proliferation, enhanced natural killer cell-mediated cytotoxicity, and increased the phagocytosis and nitric oxide production of macrophages. Moreover, these two fractions caused a significant (P<0.05) stimulation of cytokine secretion of both splenocytes and macrophages. These findings suggest that Dendrobium officinale polysaccharides should be explored as novel potential immunomodulators.

Dendrobium officinale polysaccharides ameliorate the abnormality of aquaporin 5, pro-inflammatory cytokines and inhibit apoptosis in the experimental Sjögren's syndrome mice

Sjögren's syndrome (SS) is a chronic autoimmune disease with exocrine glands disorder. Our previous work demonstrated the protective effect of Dendrobium officinale polysaccharides (DP) both on the phenotypes of patients and animal model with SS. In this study, we expand these observations to explore the possible mechanisms. The experimental SS mice model was established with or without the administration of DP (20mg/ml). The time frame of lymphocytes infiltration, apoptotic indicators such as Bax, Bcl-2 and caspase-3 were determined in submandibular gland (SG), as well as the subsequent mRNA expression of cytokines such as TNF-α, IL-1beta and IL-6. The expression and localization of aquaporin-5 (AQP-5) was examined by Western blot and immunofluorescent staining. As the result, DP could suppress the progressive lymphocytes infiltration and apoptosis, and balance the chaos of pro-inflammatory cytokines in the SG. Further, DP ameliorated the abnormalities of AQP-5 and maintained its functional importance of saliva secretion. In addition, the protection of AQP-5 by DP from human TNF-α was supported by an in vitro study on A-253 cell line. Our study further supported the efficacy of DP as the promising candidate for the therapy of SS.