The bioactivities and biotechnological production approaches of carotenoids derived from microalgae and cyanobacteria.

Microalgae and cyanobacteria are a rich source of carotenoids that are well known for their potent bioactivities, including antioxidant, anti-cancer, anti-proliferative, anti-inflammatory, and anti-obesity properties. Recently, many interests have also been focused on the biological activities of these microalgae/cyanobacteria-derived carotenoids, such as fucoxanthin and ß-carotene potential to be the salutary nutraceuticals, on treating or preventing human common diseases (e.g., cancers). This is due to their special chemical structures that demonstrate unique bioactive functions, in which the biologically active discrepancies might attribute to the different spatial configurations of their molecules. In addition, their abundance and bioaccessibilities make them more popularly applied in food and pharmaceutical industries, as compared to the macroalgal/fungal-derived ones. This review is focused on the recent studies on the bioactivities of fucoxanthin and some carotenoids derived from microalgae and cyanobacteria in relationship with human health and diseases, with emphasis on their potential applications as natural antioxidants. Various biotechnological approaches employed to induce the production of these specific carotenoids from the culture of microalgae/cyanobacteria are also critically reviewed. These well-developed and emerging biotechnologies present promise to be applied in food and pharmaceutical industries to facilitate the efficient manufacture of the bioactive carotenoid products derived from microalgae and cyanobacteria.

Effects of Oat ß-Glucan and Inulin on Alleviation of Nonalcoholic Steatohepatitis Aggravated by Circadian Disruption in C57BL/6J Mice.

This was the first study that examined the effects of oat ß-glucan and inulin on diet-induced nonalcoholic steatohepatitis (NASH) in circadian-disrupted (CD)-male C57BL/6J mice. CD intensified NASH, significantly increasing alanine aminotransferase and upregulating hepatic tumor necrosis factor α (TNFα) and transforming growth factor ß 1 (TGFß1). However, these observations were significantly alleviated by oat ß-glucan and inulin treatments. Compared to CD NASH mice, oat ß-glucan significantly decreased the liver index, aspartate aminotransferase (AST), and insulin. In prebiotic-treated and CD NASH mice, significant negative correlations were found between enrichment of Muribaculaceae bacterium Isolate-036 (Harlan), Muribaculaceae bacterium Isolate-001 (NCI), and Bacteroides ovatus after oat ß-glucan supplementation with TNFα and TGFß1 levels; and enrichment of Muribaculaceae bacterium Isolate-110 (HZI) after inulin supplementation with AST level. In conclusion, oat ß-glucan and inulin exhibited similar antiliver injury, anti-inflammatory, and antifibrotic activities but had no effect on cecal short-chain fatty acids and gut microbiota diversity in CD NASH mice.

Enhanced In Vitro Anti-Photoaging Effect of Degraded Seaweed Polysaccharides by UV/H2O2 Treatment.

The high molecular weight and poor solubility of seaweed polysaccharides have limited their function and application. In this study, ultraviolet/hydrogen peroxide (UV/H2O2) treatment was used to prepare low-molecular-weight seaweed polysaccharides from Sargassum fusiforme. The effects of UV/H2O2 treatment on the physicochemical properties and anti-photoaging activity of S. fusiforme polysaccharides were studied. UV/H2O2 treatment effectively degraded polysaccharides from S. fusiforme (DSFPs), reducing their molecular weight from 271 kDa to 26 kDa after 2 h treatment. The treatment did not affect the functional groups in DSFPs but changed their molar percentage of monosaccharide composition and morphology. The effects of the treatment on the anti-photoaging function of S. fusiforme polysaccharides were investigated using human epidermal HaCaT cells in vitro. DFSPs significantly improved the cell viability and hydroxyproline secretion of UVB-irradiated HaCaT cells. In particular, DSFP-45 obtained from UV/H2O2 treatment for 45 min showed the best anti-photoaging effect. Moreover, DSFP-45 significantly increased the content and expression of collagen I and decreased those of pro-inflammatory cytokines, including interleukin-1ß, interleukin-6, and tumor necrosis factor-α. Thus, UV/H2O2 treatment could effectively improve the anti-photoaging activity of S. fusiforme polysaccharides. These results provide some insights for developing novel and efficient anti-photoaging drugs or functional foods from seaweed polysaccharides.

A Tetrazine-Caged Carbon-Dipyrromethene as a Bioorthogonally Activatable Fluorescent Probe.

A water-soluble 1,2,4,5-tetrazine-substituted carbon-dipyrromethene (C-DIPY) was synthesized from the previously reported carbonyl pyrrole dimer through a two-step procedure. Owing to the presence of a tetrazine moiety, the fluorescence emission of this compound was largely quenched in phosphate-buffered saline at pH 7.4. Upon addition of a bicyclo[6.1.0]non-4-yne (BCN) derivative, the tetrazine-based quenching component of the compound was disrupted through the inverse electron-demand Diels-Alder reaction to restore the fluorescence in up to 6.6-fold. This bioorthogonal activation was also demonstrated using U-87 MG human glioblastoma cells, in which the fluorescence intensity of this C-DIPY could be enhanced by 8.7-fold upon post-incubation with the BCN derivative. The results showed that this tetrazine-caged C-DIPY can serve as a bioorthogonally activatable fluorescent probe for bioimaging. The compound, however, was found to reside preferentially in the lysosomes instead of the mitochondria of the cells as predicted based on its cationic character, which could be attributed to its energy-dependent endocytic cellular uptake pathway, for which lysosomes are the end station.

Fungal ß-Glucan-Based Nanotherapeutics: From Fabrication to Application.

Fungal ß-glucans are naturally occurring active macromolecules used in food and medicine due to their wide range of biological activities and positive health benefits. Significant research efforts have been devoted over the past decade to producing fungal ß-glucan-based nanomaterials and promoting their uses in numerous fields, including biomedicine. Herein, this review offers an up-to-date report on the synthetic strategies of common fungal ß-glucan-based nanomaterials and preparation methods such as nanoprecipitation and emulsification. In addition, we highlight current examples of fungal ß-glucan-based theranostic nanosystems and their prospective use for drug delivery and treatment in anti-cancer, vaccination, as well as anti-inflammatory treatments. It is anticipated that future advances in polysaccharide chemistry and nanotechnology will aid in the clinical translation of fungal ß-glucan-based nanomaterials for the delivery of drugs and the treatment of illnesses.

Enzyme-Responsive Double-Locked Photodynamic Molecular Beacon for Targeted Photodynamic Anticancer Therapy.

An advanced photodynamic molecular beacon (PMB) was designed and synthesized, in which a distyryl boron dipyrromethene (DSBDP)-based photosensitizer and a Black Hole Quencher 3 moiety were connected via two peptide segments containing the sequences PLGVR and GFLG, respectively, of a cyclic peptide. These two short peptide sequences are well-known substrates of matrix metalloproteinase-2 (MMP-2) and cathepsin B, respectively, both of which are overexpressed in a wide range of cancer cells either extracellularly (for MMP-2) or intracellularly (for cathepsin B). Owing to the efficient Förster resonance energy transfer between the two components, this PMB was fully quenched in the native form. Only upon interaction with both MMP-2 and cathepsin B, either in a buffer solution or in cancer cells, both of the segments were cleaved specifically, and the two components could be completely separated, thereby restoring the photodynamic activities of the DSBDP moiety. This PMB could also be activated in tumors, and it effectively suppressed the tumor growth in A549 tumor-bearing nude mice upon laser irradiation without causing notable side effects. In particular, it did not cause skin photosensitivity, which is a very common side effect of photodynamic therapy (PDT) using conventional "always-on" photosensitizers. The overall results showed that this "double-locked" PMB functioned as a biological AND logic gate that could only be unlocked by the coexistence of two tumor-associated enzymes, which could greatly enhance the tumor specificity in PDT.

Gene expression profile analysis of gallic acid-induced cell death process.

Gallic acid is a natural phenolic compound that displays anti-cancer properties in clinically relevant cell culture and rodent models. To date, the molecular mechanism governing the gallic acid-induced cancer cell death process is largely unclear, thus hindering development of novel therapeutics. Therefore, we performed time-course RNA-sequencing to reveal the gene expression profiles at the early (2nd hour), middle (4th and 6th hour), and late (9th hour) stages of the gallic acid-induced cell death process in HeLa cells. By Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses, we found significant changes in transcription of the genes in different types of cell death pathways. This involved the ferroptotic cell death pathway at the early stage, apoptotic pathway at the middle stage, and necroptotic pathway at the late stage. Metabolic pathways were identified at all the stages, indicating that this is an active cell death process. Interestingly, the initiation and execution of gallic acid-induced cell death were mediated by multiple biological processes, including iron and amino acid metabolism, and the biosynthesis of glutathione, as targeting on these pathways suppressed cell death. In summary, our work provides a dataset with differentially expressed genes across different stages of cell death process during the gallic acid induction, which is important for further study on the control of this cell death mechanism.

Structural characteristics and anti-inflammatory activity of UV/H2O2-treated algal sulfated polysaccharide from Gracilaria lemaneiformis.

The study aimed to study the effects on structural characteristics and anti-inflammatory activities of algal sulfated polysaccharides isolated from Gracilaria lemaneiformis (GLP) after a combined treatment of UV irradiation (average irradiance of 6500 mJ/cm2) and H2O2 (50 mmol/L) for various time periods up to 60 min. After a 30-min treatment, the molecular weight and particle size of GLP was decreased by 15 and 2.6 fold, respectively with small but significant decrease in the contents of total sugars, uronic acids and proteins. There seemed to have no starch and the presence of longer side chains of branches in the GLP samples before and after UV/H2O2 treatment based on the I2-KI assay. Scanning electron microscope and atomic force microscope analysis confirmed that the UV/H2O2 treatment could modify the surface morphology of GLP. GLP treated for 5 min possessed the strongest in vitro anti-inflammatory activity by inhibiting the production of nitric oxide, tumor necrosis factor-α and interleukin-6 by 60.49%, 62.81% and 36.29%, respectively in IEC-6 cells when compared to the model. Therefore, UV/H2O2 treatment had the potential to enhance the anti-inflammatory activity of algal sulfated polysaccharides.

The Immunomodulating Properties of Tiger Milk Medicinal Mushroom, Lignosus rhinocerus TM02® Cultivar (Agaricomycetes) and Its Associated Carbohydrate Composition.

Natural compounds found in Lignosus rhinocerus like polysaccharides and polysaccharide-protein complexes have the capabilities to modulate the immune system. It possesses antitumor and anti-inflammatory properties and is commonly used in Southeast Asia and Southern China to alleviate illness. To investigate its immunomodulating properties, composition of polysaccharides and the expression of cytokines/chemokines from L. rhinocerus (TM02®) cultivar treated RAW 264.7 were explored. It was revealed, CWE contains linear polysaccharides with 1,4-linkages and rhinoprolycan fraction (HMW & MMW) possesses 1,4-Glcp and 1,6-Glcp backbone and branched chain (1,3,6-Glcp, 1,4,6-Glcp, 1,3,6-Glcp, 1,2,4,6-Glcp). Cytokines profile showed upregulation from CWE (IL-5: 12.078 ± 1.225), HMW (IL-6: 7.297 ± 0.338; TIMP-1: 3.358 ± 0.200), MMW (IL-5: 15.412 ± 5.823; TIMP-1: 1.747 ± 0.053), and LMW (MIP-2: 3.495 ± 0.416; TIMP-1: 7.573 ± 0.088) and possible involvement of NF-κB and MAPK signaling pathway. Further in vivo studies are needed to fully understand the immunomodulatory effects of TM02®.

Immunomodulatory Properties of Water-Soluble Polysaccharides Extracted from the Fruiting Body of Chinese Caterpillar Mushroom, Ophiocordyceps sinensis Cultivar OCS02® (Ascomycetes).

Ophiocordyceps sinensis (=Cordyceps sinensis) has been known for its various medicinal properties, in particular immunomodulatory activities associated with its polysaccharides. In this study, the fruiting body of O. sinensis cultivar OCS02® was investigated for its chemical composition and monosaccharide profile. Cold water extract (CWE) obtained from this fruiting body was fractionated by molecular weight (MW) into high (HMW), medium (MMW), and low (LMW) fractions. Polysaccharides in the extract and fractions were identified as heteroglycans containing mostly glucose and mannose with small amounts of galactose, fucose, arabinose, and xylose. The immunomodulatory potential of these heteroglycans was evaluated by induction of cytokine/chemokine secretion using murine macrophage RAW 264.7. All treatments showed significant modulation of IL-6, IL-9, MIP-2, and TIMP-1, especially for CWE, HMW, and MMW, which might be due to their high ratios of glucose and the presence of protein. Further investigation on the structure-function relationship of these fruiting body polysaccharide fractions is needed to delineate the underlying mechanism of their immunomodulatory effect both in vitro and in vivo.

Gallic Acid Triggers Iron-Dependent Cell Death with Apoptotic, Ferroptotic, and Necroptotic Features.

Gallic acid (GA) is a natural anti-cancer compound that can be found in many food sources, including edible mushrooms, fruits, and vegetables. Studies generally attribute the anti-cancer activity of GA to the induction of apoptosis. Here, we reported that GA activated iron-dependent cell death mechanisms with apoptotic, ferroptotic, and necroptotic features. Our time-lapse live-cell microscopy study demonstrated that GA could induce coexistence of multiple types of cell death pathways, including apoptosis characterized by mitochondrial cytochrome c release and caspase-3 activation, ferroptosis characterized by lipid peroxidation, and necroptosis characterized by the loss of plasma membrane integrity. This GA-induced cell death could be completely suppressed by exposure to an iron chelator deferoxamine, indicating that it is an iron-dependent cell death process. Importantly, MLKL (mixed lineage kinase domain-like protein) inhibitor necrosulfonamide exerted a synergistic effect by increasing the sensitivity of cancer cells to GA. Taken together, our results provide new mechanistic insights, and also suggest new strategies to enhance the efficacy of this natural anti-cancer compound by identifying the agents that can promote or suppress the GA-induced cell death process.

Enhancement of the Production of Bioactive Microalgal Metabolites by Ultraviolet Radiation (UVA 365 nm).

Two marine microalgae, Nitzschia closterium and Isochrysis zhangjiangensis, treated for 9 days with photosynthetically active radiation (PAR), were subjected to 3 days of ultraviolet light band A at 365 nm (UVA365) followed by a 3 day post-UVA PAR treatment. Compared with the control that only had PAR treatment, UVA365 treatment significantly ( p < 0.05) increased the amounts of total xanthophylls in N. closterium and I. zhangjiangensis by up to 3.53- and 1.23-fold, respectively, after 3 days of UVA365 irradiation. In particular, UVA365 treatment markedly ( p < 0.05) increased two major bioactive xanthophyll pigments, fucoxanthin in N. closterium and diadinoxanthin in I. zhangjiangensis, by up to 1.97- and 1.52-fold, respectively. UVA365 treatment significantly ( p < 0.05) increased the accumulation of another bioactive microalgal metabolite, total mycosporine-like amino acids, in N. closterium and I. zhangjiangensis by up to 1.40- and 1.30-fold, respectively. UVA365 irradiation has potential as an efficient approach for enhancing the production of valuable microalgal metabolites.

Occurrence and biosynthesis of carotenoids in phytoplankton.

Naturally occurring carotenoids are important sources of antioxidants, anti-cancer compounds and anti-inflammatory agents and there is thus considerable market demand for their pharmaceutical applications. Carotenoids are widely distributed in marine and freshwater organisms including microalgae, phytoplankton, crustaceans and fish, as well as in terrestrial plants and birds. Recently, phytoplankton-derived carotenoids have received much attention due to their abundance, rapid rate of biosynthesis and unique composition. The carotenoids that accumulate in particular phytoplankton phyla are synthesized by specific enzymes and play unique physiological roles. This review focuses on studies related to the occurrence of carotenoids in different phytoplankton phyla and the molecular aspects of their biosynthesis. Recent biotechnological advances in the isolation and characterization of some representative carotenoid synthases in phytoplankton are also discussed.

Comparison of the Composition and Antioxidant Activities of Phenolics from the Fruiting Bodies of Cultivated Asian Culinary-Medicinal Mushrooms.

The composition profile and the antioxidant properties of phenolics in water extracts obtained from the fresh fruiting bodies of 4 common cultivated Asian edible mushrooms-Agrocybe aegerita, Pleurotus ostreatus, P. eryngii, and Pholiota nameko were compared. The water extract from A. aegerita (AaE) had the highest total phenolic content (TPC) at 54.18 ± 0.27 gallic acid equivalents (µmol/L)/mg extract (P < 0.05), as measured by the Folin-Ciocalteu method, and consisted of the largest number (including gallic acid, protocatechuic acid, chlorogenic acid, ferulic acid, and sinapic acid) and total amounts of phenolic acids identified by Fourier transform-ion cyclotron resonance mass spectrometry. The water extract of Ph. nameko was found to have the second-highest TPC (43.55 ± 0.10 gallic acid equivalents [µmol/L]/mg extract), followed by the water extract of P. eryngii and the water extract of P. ostreatus (39.55 ± 0.25 and 39.02 ± 0.30 gallic acid equivalents/mg extract, respectively). The scavenging activities of the water extracts from these mushrooms were evaluated against 2,2-diphenyl-l-(2,4,6-trinitrophenyl) hydrazyl diphenylpicrylhydrazyl (DPPH), superoxide anion radicals, hydroxyl radicals, and hydrogen peroxide. Based on halfmaximal effective concentrations, AaE was more effective in scavenging hydrogen peroxide (<0.05), followed by DPPH (0.51 mg/mL), superoxide anion radicals (0.85 mg/mL) and hydroxyl radicals (5.94 mg/mL), then the other mushroom water extracts. The differences in the half-maximal effective concentrations of individual mushroom water extracts were probably the result of the different numbers and amounts of individual phenolic acids in the extracts. The antioxidant activities of the mushroom water extracts were correlated with their TPC. The strongest antioxidant properties of AaE were consistent with its highest TPC and with the largest number and amount of phenolics identified in the extract. These results indicated that cultivated edible mushrooms could be a potential source of natural antioxidants with free radical scavenging properties for application as a functional food ingredient.

Phytochemical profiles of marine phytoplanktons: an evaluation of their in vitro antioxidant and anti-proliferative activities.

Marine microorganisms such as phytoplanktons are a rich resource of bioactive components with antioxidant and anti-proliferative activities that can act as novel functional food ingredients. In this study, the pigment profiles, total mycosporine-like amino acids (MAAs) and total phenolic contents (TPCs) in solvent extracts including 90% acetone and methanol from five marine phytoplanktons including Nitzschia closterium (Bacillariophyta), Isochrysis zhangjiangensis (Haptophyta), Platymonas subcordiformis (Chlorophyta), Porphyridium cruentum (Rhodophyta) and Synechocystis pevalekii (Cyanobacteria) were analyzed. Each phytoplankton from different phyla had its unique compositions of carotenoids and chlorophylls. The 90% acetone extract from I. zhangjiangensis had the highest MAA content (508.30 µg per g DW) while the methanol extract from N. closterium had the highest level of TPCs (6.15 mg GAE per g DW) among all the phytoplanktons investigated. The amounts of total carotenoids in all the 90% acetone extracts from the five phytoplanktons as well as total MAAs in those from within the four microalgae except S. pevalekii were found to be strongly correlated with their antioxidant activities evaluated by the DPPH, TEAC and FRAP assays. Only the level of total carotenoids in the phytoplanktons was correlated with their anti-proliferative activities assessed by the MTT assays using MCF-7 cells. Therefore, individual carotenoid pigments seemed to be mainly responsible for the antioxidant and anti-proliferative (or anticancer) activities found in the solvent extracts of the five phytoplanktons. Hence these phytoplanktons have the potential as novel sources of natural food antioxidants and anticancer agents to be used as active ingredients in functional food products.

Antitumor and Immunomodulating Activities of Exopolysaccharide Produced by Big Cup Culinary- Medicinal Mushroom Clitocybe maxima (Higher Basidiomycetes) in Liquid Submerged Culture.

Water-soluble polysaccharides extracted from mushrooms have been found to have some physiological effects. In this study, exopolysaccharides (EPSs) were extracted by alcohol precipitation from cultivated broth of the mushroom Clitocybe maxima. EPSs with molecular weights of 10(4) and 10(5) Da were obtained by ultrafiltration; they are referred to as EPA and EPB, respectively. The major components of these EPSs were glucose, galactose, mannose, rhamnose, and arabinose. ICR mice with artificially induced metastatic pulmonary tumors were fed a daily diet containing EPA or EPB at doses of 8, 20, or 50 mg/kg. Results showed that the proliferation of pulmonary sarcoma lesions was lower in the groups fed EPS. In addition, the numbers of total T cells, CD4+ cells, CD8+ cells, and macrophages significantly increased in EPS-fed mice compared with the negative control group. The antitumor and immunomodulating effects observed in the EPB-fed groups were higher than those of EPA-fed groups. These results demonstrate the ability of EPSs of C. maxima to inhibit tumor cells while enhancing immune response.

Water extract from Pleurotus pulmonarius with antioxidant activity exerts in vivo chemoprophylaxis and chemosensitization for liver cancer.

Chemoprophylaxis and chemosensitization are promising strategies to combat human cancers. Natural antioxidant agents show great promise in cancer therapy, and the use of edible mushrooms against cancer is receiving more interest globally. In this study, the radical scavenging activities including diphenyl-1-picrylhydrazyl, superoxide anion radical, hydroxyl radical, and hydrogen peroxide were compared among hot water extracts from 3 edible mushrooms, among which Pleurotus pulmonarius (Pp) possessed the highest antioxidant potential. Oral administration of Pp 2 wk in advance could markedly inhibit the incidence and size of tumor (Huh7 liver cancer cells) with an inhibition rate of 93.1% in nude mice. No obvious side effect was observed in the Pp-treated mice as indicated by their body weight and histological analysis of major organs. The cancer prevention by Pp treatment might be explained by the inhibition of cancer cell proliferation indicated by reduction of ki-67 staining and the inactivation of phosphoinositide 3-kinase (PI3K)/AKT signaling pathway in the Pp-treated mice. Furthermore, a significant synergistic effect was observed when the mice were treated with a combination of low dose of cisplatin and Pp. Taken together, these results suggest the potential application of Pp as an adjuvant in the chemotherapy of liver cancer.

Extract of Pleurotus pulmonarius suppresses liver cancer development and progression through inhibition of VEGF-induced PI3K/AKT signaling pathway.

Liver cancer or hepatocellular carcinoma is one of the leading causes of cancer-related deaths. Conventional chemotherapies are limited by the development of drug resistance and various side effects. Because of its non-toxicity and potent biopharmacological activity, metabolites derived from mushrooms have received more attention in cancer therapy. Our previous studies have demonstrated the anticancer effects of polysaccharide-protein complexes derived from the Pleurotus mushrooms. The aim of this study was to investigate the underlying molecular mechanism of the anticancer activity of a hot water extract containing a polysaccharide-protein complex isolated from Pleurotus pulmonarius (PP) in liver cancer cells. Our results indicated that exposure of liver cancer cells to PP not only significantly reduced the in vitro cancer cell proliferation and invasion but also enhanced the drug-sensitivity to the chemotherapeutic drug Cisplatin. Both oral administration and intraperitoneal injection of PP significantly inhibited the tumor growth in xenograft BALB/c nude mice. PP triggered a marked suppression of the PI3K/AKT signaling pathway in liver cancer cells in vitro and in vivo, and overexpression of the constitutively active form of AKT, Myr-AKT, abrogated this effect and the inhibited proliferation and invasion by PP. Both western blot and ELISA results showed that PP-treated liver cancer cells had reduced expression and secretion of vascular endothelial growth factor (VEGF). Addition of recombinant human VEGF attenuated the inhibitory effects of PP on PI3K/AKT pathway and the cancer phenotypes. Our results demonstrated that PP suppressed the proliferation, invasion, and drug-resistance of liver cancer cells in vitro and in vivo, mediated by the inhibition of autocrine VEGF-induced PI3K/AKT signaling pathway. This study suggests the potential therapeutic implication of PP in the treatment of human liver cancer.

Immunopotentiation and anti-tumor activity of carboxymethylated-sulfated beta-(1-->3)-d-glucan from Poria cocos.

A carboxymethylated-sulfated derivative of (1-->3)-beta-d-glucan (PCS3-II) extracted from Poria cocos was synthesized and coded as CS-PCS3-II. Results of infrared (IR) and Carbon-13 nuclear magnetic resonance spectroscopy ((13)C NMR) indicated that CS-PCS3-II contained carboxymethyl and sulfate groups with a degree of substitution (DS) of 1.05 and 0.36 respectively. By using size exclusion chromatography (SEC) combined with laser light scatting (LLS), the dependence of radius of gyration ((z)(1/2)) on the molecular weight (M(w)) for CS-PCS3-II was established as (z)(1/2) = 6.92 x 10(-2)M(w)(0.59) in 0.15M NaCl solution at 25 degrees C, suggesting that CS-PCS3-II existed as an extended flexible chain. CS-PCS3-II exhibited significantly higher inhibition ratio to Sarcoma 180 tumor in BALB/c mice than PCS3-II. Histological examination of tumor cells treated with CS-PCS3-II had signs of necrosis and apoptosis. It is postulated that introduction of the carboxymethyl and sulfate groups to PCS3-II increased its possible contact with the receptors of immune cells through hydrogen binding and electrostatic attraction, leading to a stronger immunological responses that resulted in inhibition of tumor cell proliferation. Moreover, there were significant increases in phagocyte and thymus indexes, spleen index, hemolytic activity as well as spleen antibody production and delayed type hypersensitivity (DTH), suggesting that CS-PCS3-II could significantly enhance immunpotentiation in mice.

Effect of molecular mass on antitumor activity of heteropolysaccharide from Poria cocos.

A water-soluble heteropolysaccharide ac-PCM0 from Poria cocos was successfully fractionated using a preparative size exclusion chromatography (SEC) column, and their weight-average molecular mass (M(w)) was characterized by analytical SEC combined with laser light scattering (SEC-LLS). The results indicate that the fractions having relatively high M(w) exhibited higher inhibition ratio in vivo antitumor activity than those having M(w) below 3.29 x 10(4). However, the relatively low molecular mass was beneficial to the in vitro antitumor activity. Moreover, ac-PCM0 has a significantly higher enhancement ratio of the body weight than 5-fluorouracil, and its 50% lethal dose is above 1250 mg/kg, indicating a nontoxic nature.