Danfei Huang

Ultrasonic-assisted extraction, antimicrobial and antioxidant activities of Cyclocarya paliurus (Batal.) Iljinskaja polysaccharides

Recently, renewed interest has grown in the use of ultrasonic-assisted extraction as an alternative approach to the traditional extraction methods. In this study, this novel extraction method was used to isolate polysaccharides from Cyclocarya paliurus (Batal.) Iljinskaja, and response surface methodology (RSM) was employed to optimize the extraction conditions. The optimal conditions for the extraction of polysaccharides were determined to be the ratio of liquid to solid of 8, extraction time of 59 min and extraction temperature of 58 °C. Under these optimal conditions, the yield of polysaccharides obtained was 4.91 ± 0.11%, which was well matched with the value predicted by the model. In vitro antioxidant assays showed that the polysaccharides exhibited strong DPPH radicals (92.09% at 0.25 mg/ml) and self-oxidation of 1,2,3-phentriol (37.22% at 1 mg/ml) scavenging activities, moderate hydroxyl radicals (43.18% at 1 mg/ml) scavenging activity and lipid peroxidation inhibitory effect (31.66% at 1 mg/ml). In addition, the polysaccharides showed moderate antimicrobial activity.

Immunomodulatory effect of Ganoderma atrum polysaccharide on CT26 tumor-bearing mice

Ganoderma atrum has attracted great attention for its antitumor activity. However, the mechanism remains unclear. A G. atrum polysaccharide (PSG-1) showed pronounced antitumor activity in this study. PSG-1 did not kill CT26 cells directly, but inhibited the proliferation of CT26 cells via the activation of peritoneal macrophages (MΦ). In vivo, PSG-1 significantly suppressed the tumor growth in CT26 tumor-bearing mice. The treatment caused a significant increase in the immune organ index and the phagocytosis of macrophages. The production of TNF-α, IL-1β and nitric oxide also increased. Furthermore, we found that PSG-1 acted on Toll-like receptor (TLR) 4, signaled through p38 MAPK pathway, then activated NF-κB and stimulated TNF-α production. We further found that PSG-1 increased the expression of TLR4 and NF-κB, the degradation of IκBα and the phosphorylation of p38 MAPK. In summary, we have demonstrated that PSG-1 could activate macrophages via TLR4-dependent signaling pathways, improve immunity and inhibit tumor growth.

Immunomodulatory activity of the seeds of Plantago asiatica L.

ETHNOPHARMACOLOGICAL RELEVANCE The seeds of Plantago asiatica L. were often used as a traditional Chinese medicine for some immunologically weak patients suffering from chronic illness. These uses could be related to immunomodulatory properties of the plant. AIM OF THE STUDY In this study, effects of extract of the seeds of Plantago asiatica L. (ES-PL) were investigated on the maturation of dendritic cells (DCs), which play significant role in primary immune system. MATERIALS AND METHODS The phenotypes of DCs were analyzed by using flow cytometry while phagocytosis was assessed by the uptake of FITC-dextran. Antigen presenting ability to allogeneically naïve or syngeneically primed T lymphocytes was examined by the lymphocyte proliferation of mixed lymphocyte reaction (MLR). In addition, the level of chemokine receptor CCR7 mRNA was determined by RT-PCR. RESULTS DCs treated with ES-PL expressed higher levels of MHC class II molecules and major costimulatory molecules such as CD80 and CD86. Functional maturation of DCs treated with ES-PL was confirmed by decreased mannose receptor-mediated endocytosis and increased antigen presenting abilities to allogeneically naïve or syngeneically primed T lymphocytes. The CCR7 mRNA expression in DCs treated with ES-PL was also enhanced. CONCLUSIONS These results indicated that ES-PL could induce the maturation of murine DCs.

Polysaccharide from Ganoderma atrum evokes antitumor activity via Toll-like receptor 4-mediated NF-κB and mitogen-activated protein kinase signaling pathways.

Ganoderma atrum has been used as a traditional Chinese medicine for centuries. In this study, the antitumor activity of a novel G. atrum polysaccharide (PSG-1) was investigated in vitro and in vivo using S180 tumor-bearing mice. The results showed that PSG-1 significantly inhibited the proliferation of S180 via the activation of macrophages in a dose-dependent manner. PSG-1-primed macrophages exhibited a higher tumoricidal activity than untreated macrophages. Administration of PSG-1 significantly inhibited the growth of transplantable sarcoma S180-bearing mice and increased macrophage phagocytosis and the levels of cytokines and nitride oxide. Expression of Toll-like receptor (TLR) 4 in the membrane was markedly increased in PSG-1-treated groups, suggesting that it may be a possible receptor for PSG-1. PSG-1 also promoted the translocation of the p65 subunit of NF-κB from cytosol to nucleus and the degradation of IκBα. Moreover, the phosphorylation of p38 mitogen-activated protein kinase (MAPK), extracellular signal-regulated kinases 1/2, and c-Jun N-terminal kinase in macrophages was improved by PSG-1 in a dose-dependent manner. Therefore, it is suggested that PSG-1 may elicit its antitumor effect by improving immune system functions through TLR4-mediated NF-κB and MAPK signaling pathways.

Chemoprotective effects of Ganoderma atrum polysaccharide in cyclophosphamide-induced mice

In this study, the chemoprotective effects of Ganoderma atrum polysaccharide (PSG-1) in cyclophosphamide (Cy) treated mice were investigated. In Cy-treated mice, PSG-1 treatment accelerated recovery dose-dependently of peripheral red blood cells, white blood cells and platelets, enhanced splenic natural killer cell activity and cytotoxic T lymphocyte activity. In addition, PSG-1 elevated CD4(+) T lymphocyte counts as well as the CD4(+)/CD8(+) ratio dose-dependently. Furthermore, PSG-1 restored the levels of IL-2, INF-γ, IL-10, IgA, IgM and IgG, as well as hemolysin in the sera. Finally, PSG-1 can also significantly increase the total antioxidant capacity, activities of superoxidase dismutase, catalase and glutathione peroxidase, and decrease the malondialdehyde level in vivo. These findings indicate that PSG-1 plays an important role in the protection against myelosuppression and immunosuppression and oxidative stress in Cy-treated mice and could be a potential immunomodulatory agent.

A novel polysaccharide from Ganoderma atrum exerts antitumor activity by activating mitochondria-mediated apoptotic pathway and boosting the immune system.

Ganoderma is a precious health-care edible medicinal fungus in China. A novel Ganoderma atrum polysaccharide (PSG-1) is the main bioactive component. We investigated the antitumor effect and molecular mechanisms of PSG-1. It exhibited no significant effect on cell proliferation directly. In contrast, administration of PSG-1 markedly suppressed tumor growth in CT26 tumor-bearing mice. It was observed that PSG-1 caused apoptosis in CT26 cells. Apoptosis was associated with loss of mitochondrial membrane potential, enhancement of mitochondrial cytochrome c release and intracellular ROS production, elevation of p53 and Bax expression, downregulation of Bcl-2, and the activation of caspase-9 and -3. Moreover, PSG-1 enhanced immune organ index and promoted lymphocyte proliferation as well as cytokine levels in serum. Taken together, our data indicate that PSG-1 has potential antitumor activity in vivo by inducing apoptosis via mitochondria-mediated apoptotic pathway and enhances host immune system function. Therefore, PSG-1 could be a safe and effective antitumor, bioactive agent or functional food.

Effect of phenylethanoid glycosides and polysaccharides from the seed of Plantago asiatica L. on the maturation of murine bone marrow-derived dendritic cells.

The seed of Plantago asiatica L. is one of the most popular folk herbal medicines used in China and other Asian countries. In this study, phenylethanoid glycosides and polysaccharides were isolated from the seed of P.asiatica L. by using phytochemical investigation methods. A screening model of immunological activity by using dendritic cells as target cells was established to investigate the effects of these compounds on the phenotypic and functional maturation of dendritic cells. Compared with untreated cells, dendritic cells treated with acteoside, isoacteoside or polysaccharides expressed higher level of class II MHC and costimulatory molecule CD86 (B7-2). Functional maturation was confirmed by decreased endocytosis and increased naïve T cell stimulatory activity of dendritic cells. These results showed that acteoside, isoacteoside and polysaccharides from the seed of P.asiatica L. had significant immunoenhancing activity by inducing the maturation of dendritic cells.

Toll-like receptor 4-mediated ROS signaling pathway involved in Ganoderma atrum polysaccharide-induced tumor necrosis factor-α secretion during macrophage activation.

Ganoderma atrum has been used as Chinese traditional medicine and healthful mushroom for thousands of years. The polysaccharide is regarded as the major bioactive substances in G. atrum. To delineate the underlying mechanism and signaling cascade involved in the immunomodulatory property of G. atrum polysaccharide (PSG-1). Specifically, this study is designed to examine the possibility of TLR4 as a candidate receptor interacted with G. atrum polysaccharide (PSG-1) and elucidate the role of reactive oxygen species (ROS) in PSG-1-induced tumor necrosis factor-α (TNF-α) production during macrophage activation. Flow cytometric and confocal laser-scanning microscopy analysis showed that fluorescence-labeled PSG-1 bind specifically to the macrophages. Moreover, PSG-1 stimulated TNF-α secretion of peritoneal macrophages from C3H/HeN mice, but not from C3H/HeJ mice. PSG-1-indcued TNF-α production was suppressed by anti-TLR4 mAb. Furthermore, ROS production was mediated by TLR4, and NADPH oxidase-derived ROS act as upstream of phosphoinositide 3-kinase(PI3K)/Akt/mitogen-activated protein kinases(MAPKs)/nuclear factor(NF)-κB signaling pathway in the regulation of PSG-1 stimulated TNF-α production. Taken together, we conclude that PSG-1 induces TNF-α secretion through TLR4/ROS/PI3K/Akt/MAPKs/NF-κB pathways during macrophage activation. Our findings provide a molecular basis for the potential of PSG-1 as a novel immunomodulatory agent.

Simultaneous analysis of 18 mineral elements in Cyclocarya paliurus polysaccharide by ICP-AES

The contents of 18 kinds of mineral elements in Cyclocarya paliurus polysaccharide samples were determined by ICP-AES. The limits of detection (LOD) of the method for 18 elements were in the range of 0.01-3.80 mg/kg. The average recoveries obtained by the standard addition method were found between 94.34% and 105.69% (RSD, 1.01-4.23%). The results showed that C. paliurus polysaccharides were abundant in major and trace elements which are healthy for human body. The contents of Ca, Al, Mg, K, Fe, Mn and P were very high, ranging from 274.5±10.3 to 5980.0±102.7 mg/kg, while the contents of Zn, Na, Se, Cr, Pb, Cu and As ranged from 0.9±0.1 to 37.1±4.2 mg/kg. Finally, the levels of Ni, Cd, V and Co were not detected in the samples. ICP-AES is a simple, precise and efficient method for the determination of many mineral elements in polysaccharide samples simultaneously.

A novel polysaccharide from the seeds of Plantago asiatica L. induces dendritic cells maturation through toll-like receptor 4.

In this study, we investigated the effect of a polysaccharide purified from the seeds of Plantago asiatica L. (PLP-2) on the phenotypic and functional maturation of murine bone marrow-derived dendritic cells (DCs) and relevant mechanisms. The results showed that PLP-2 increased the expression of maturation markers major histocompatibility complex II, CD86, CD80, and CD40 on DCs. Consistent with the changes in the phenotypic markers, functional assay for DCs maturation showed that PLP-2 decreased DCs endocytosis and increased intracellular interleukin (IL)-12 levels and allostimulatory activity. Furthermore, using a syngeneic T cell activation model, we found that PLP-2 treated DCs presented ovalbumin antigen to T cells more efficiently as demonstrated by increased T cell proliferation. In addition, the effects of PLP-2 on DCs were significantly impaired by treating the cells with anti-TLR4 antibody prior to PLP-2 treatment, implying direct interaction between PLP-2 and TLR4 on cell surface. These results suggested that PLP-2 may induce DCs maturation through TLR4. Our results may have important implications for our understanding on the molecular mechanisms of immunopotentiating action of the polysaccharides from plants.