Structure and inducing tumor cell apoptosis activity of polysaccharides isolated from Lentinus edodes

A polysaccharide from Lentinus edodes inhibits human colon cancer cell proliferation and suppresses tumor growth in athymic nude mice

The antitumor effect of Lentinan is thought rely on the activation of immune responses; however, little is known about whether Lentinan also directly attacks cancer cells. We therefore investigated the direct antitumor activity of SLNT (a water-extracted polysaccharide from Lentinus edodes) and its probable mechanism. We showed that SLNT significantly inhibited proliferation of HT-29 colon cancer cells and suppressed tumor growth in nude mice. Annxein V-FITC/PI, DAPI, AO/EB and H&E staining assays all showed that SLNT induced cell apoptosis both in vitro and in vivo. SLNT induced apoptosis by activating Caspase-3 via both intrinsic and extrinsic pathways, which presented as the activation of Caspases-9 and -8, upregulation of cytochrome c and the Bax/Bcl-2 ratio, downregulation of NF-κB, and overproduction of ROS and TNF-α in vitro and in vivo. Pretreatment with the caspase-3 inhibitor Ac-DEVD-CHO or antioxidant NAC blocked SLNT-induced apoptosis. These findings suggest that SLNT exerts direct antitumor effects by inducing cell apoptosis via ROS-mediated intrinsic and TNF-α-mediated extrinsic pathways. SLNT may thus represent a useful candidate for colon cancer prevention and treatment.

The chemical structure and anti-aging bioactivity of an acid polysaccharide obtained from rose buds

An acid polysaccharide, named R-PL, was extracted from rose buds by hot water (80 °C) extraction and purified by Sephadex G-200.

Purification and activity characterization of polysaccharides in the medicinal lichen Umbilicaria tornata from Taibai Mountain, China

Water-soluble polysaccharides from Umbilicaria tornata (UTP) were purified and preliminarily characterized. The antioxidant and antitumor activities of crude UTP and two purified fractions (UTP-1 and UTP-2) were evaluated using in vitro experiments. The results showed that the molecular weights of UTP-1 and UTP-2 were 84.86 and 28.66 kDa, respectively. Both UTP-1 and UTP-2 were composed of glucose and xylose, with their molar ratios being 1.3:0.9 and 0.9:4.6, respectively. In addition, crude UTP, UTP-1 and UTP-2 showed dose-dependent DPPH and hydroxyl radical scavenging and reducing activities. However, crude UTP exhibited stronger antioxidant activity than UTP-1 and UTP-2, particularly in terms of DPPH radicals. Crude UTP and the two purified fractions inhibited the growth of HeLa, HepG2, A375, MCF-7, SGC7901 and Caco2 cancer cells in vitro. Compared with UTP-1 and UTP-2, crude UTP presented significantly higher antitumor activity in vitro against HeLa and HepG2 cells (p < 0.05). These findings provide a scientific basis for the deeper exploration and resource development of U. tornata.

Isolation, Purification and Structural Characterization of Two Novel Water-Soluble Polysaccharides from Anredera cordifolia

Anredera cordifolia, a climber and member of the Basellaceae family, has long been a traditional medicine used for the treatment of hyperglycemia in China. Two water-soluble polysaccharides, ACP1-1 and ACP2-1, were isolated from A. cordifolia seeds by hot water extraction. The two fractions, ACP1-1 and ACP2-1 with molecular weights of 46.78 kDa ± 0.03 and 586.8 kDa ± 0.05, respectively, were purified by chromatography. ACP1-1 contained mannose, glucose, galactose in a molar ratio of 1.08:4.65:1.75, whereas ACP2-1 contained arabinose, ribose, galactose, glucose, mannose in a molar ratio of 0.9:0.4:0.5:1.2:0.9. Based on methylation analysis, ultraviolet and Fourier transform-infrared spectroscopy, and periodate oxidation the main backbone chain of ACP1-1 contained (1→3,6)-galacturonopyranosyl residues interspersed with (1→4)-residues and (1→3)-mannopyranosyl residues. The main backbone chain of ACP2-1 contained (1→3)-galacturonopyranosyl residues interspersed with (1→4)-glucopyranosyl residues.

Progress in rigid polysaccharide-based nanocomposites with therapeutic functions

Nanocomposites engineered by incorporating versatile nanoparticles into different bioactive β-glucan matrices display effective therapeutic functions.

Mushroom Polysaccharides: Chemistry and Antiobesity, Antidiabetes, Anticancer, and Antibiotic Properties in Cells, Rodents, and Humans

More than 2000 species of edible and/or medicinal mushrooms have been identified to date, many of which are widely consumed, stimulating much research on their health-promoting properties. These properties are associated with bioactive compounds produced by the mushrooms, including polysaccharides. Although β-glucans (homopolysaccharides) are believed to be the major bioactive polysaccharides of mushrooms, other types of mushroom polysaccharides (heteropolysaccharides) also possess biological properties. Here we survey the chemistry of such health-promoting polysaccharides and their reported antiobesity and antidiabetic properties as well as selected anticarcinogenic, antimicrobial, and antiviral effects that demonstrate their multiple health-promoting potential. The associated antioxidative, anti-inflammatory, and immunomodulating activities in fat cells, rodents, and humans are also discussed. The mechanisms of action involve the gut microbiota, meaning the polysaccharides act as prebiotics in the digestive system. Also covered here are the nutritional, functional food, clinical, and epidemiological studies designed to assess the health-promoting properties of polysaccharides, individually and as blended mixtures, against obesity, diabetes, cancer, and infectious diseases, and suggestions for further research. The collated information and suggested research needs might guide further studies needed for a better understanding of the health-promoting properties of mushroom polysaccharides and enhance their use to help prevent and treat human chronic diseases.

Anti-tumor effect of β-glucan from Lentinus edodes and the underlying mechanism

β-Glucans are well known for its various bioactivities, but the underlying mechanism has not been fully understood. This study focuses on the anti-tumor effect and the potential mechanism of a branched β-(1, 3)-glucan (LNT) extracted from Lentinus edodes. The in vivo data indicated that LNT showed a profound inhibition ratio of ~75% against S-180 tumor growth, even significantly higher than the positive control of Cytoxan (~54%). Interestingly, LNT sharply promoted immune cells accumulation into tumors accompanied by cell apoptosis and inhibition of cell proliferation during tumor development. Furthermore, LNT not only up-regulated expressions of the tumor suppressor p53, cell cycle arrestin p21 and pro-apoptotic proteins of Bax and caspase 3/9, but also down-regulated PARP1 and anti-apoptotic protein Bcl-2 expressions in tumor tissues. It was first found that LNT initiated p53-dependent signaling pathway to suppress cell proliferation in vitro, and the caspase-dependent pathway to induce cell apoptosis in vivo. The underlying anti-tumor mechanism was proposed that LNT activated immune responses to induce cell apoptosis through caspase 3-dependent signaling pathway and to inhibit cell proliferation possibly via p53-dependent signaling pathway in vivo. Besides, LNT inhibited angiogenesis by suppressing VEGF expression, leading to slow progression of tumors.

Immune evasion in cancer: Mechanistic basis and therapeutic strategies

Cancer immune evasion is a major stumbling block in designing effective anticancer therapeutic strategies. Although considerable progress has been made in understanding how cancers evade destructive immunity, measures to counteract tumor escape have not kept pace. There are a number of factors that contribute to tumor persistence despite having a normal host immune system. Immune editing is one of the key aspects why tumors evade surveillance causing the tumors to lie dormant in patients for years through "equilibrium" and "senescence" before re-emerging. In addition, tumors exploit several immunological processes such as targeting the regulatory T cell function or their secretions, antigen presentation, modifying the production of immune suppressive mediators, tolerance and immune deviation. Besides these, tumor heterogeneity and metastasis also play a critical role in tumor growth. A number of potential targets like promoting Th1, NK cell, γδ T cell responses, inhibiting Treg functionality, induction of IL-12, use of drugs including phytochemicals have been designed to counter tumor progression with much success. Some natural agents and phytochemicals merit further study. For example, use of certain key polysaccharide components from mushrooms and plants have shown to possess therapeutic impact on tumor-imposed genetic instability, anti-growth signaling, replicative immortality, dysregulated metabolism etc. In this review, we will discuss the advances made toward understanding the basis of cancer immune evasion and summarize the efficacy of various therapeutic measures and targets that have been developed or are being investigated to enhance tumor rejection.

Identification and effect of two flavonoids from root bark of Morus alba against Ichthyophthirius multifiliis in grass carp

Ichthyophthirius multifiliis (Ich) is an important ciliate that parasitizes gills and skin of freshwater fish and causes massive fish mortality. In this study, two flavonoids (kuwanons G and O) with anti-Ich activity were isolated by bioassay-guided fractionation from the root bark of Morus alba, an important plant for sericulture. The chemical structures of kuwanons G and O were elucidated by spectroscopic analyses. Kuwanons G and O caused 100% mortality of I. multifiliis theronts at the concentration of 2 mg/L and possessed a median effective concentration (EC50) of 0.8 ± 0.04 mg/L against the theronts. In addition, kuwanons G and O significantly reduced the infectivity of I. multifiliis theronts at concentrations of 0.125, 0.25, 0.5, and 1 mg/L. The median lethal concentrations (LC50) of kuwanons G and O to grass carp were 38.0 ± 0.82 and 26.9 ± 0.51 mg/L, which were approximately 50 and 35 times the EC50 for killing theronts. The results indicate that kuwanons G and O have the potential to become safe and effective drugs to control ichthyophthiriasis.