Phthaloyl modification of a polysaccharide from Lachnum YM262 and immunomodulatory activity

Pectin-like polysaccharide extracted from leaves Crataeva tapia promotes antioxidant, immunomodulatory and emulsifiers applied in therapeutic formulations

The objective of this work was to isolate a polysaccharide similar to pectin from Crataeva tapia leaves, not yet reported in the literature, and to evaluate its antioxidant, cytotoxic and immunomodulatory profile. Pectin was extracted from the leaves in three stages, organic solvent followed by acidified water and ethanol precipitation. With the pectin obtained, the physicochemical characterization of the molecule was carried out using high-performance liquid chromatography, Fourier-transform infrared spectroscopy, nuclear magnetic resonance (13C and 1H) and different thermal and elemental analysis. Furthermore, the antioxidant activities were evaluated in vitro, and using human peripheral blood mononuclear cell culture, cytotoxicity and immunostimulatory actions were investigated. Physical and chemical analyses showed characteristic signs of pectin. Antioxidant activity tests showed that pectin had moderate to low antioxidant activity. Furthermore, pectin did not affect the viability of erythrocytes and PBMC and induced an immunostimulatory state when it promoted the production of cytokines IL-6, IL-10 and TNF-α and increased the activation of CD8 + T lymphocytes. This study showed that pectin from Crataeva tapia is not cytotoxic and promoted a pro-inflammatory profile in peripheral blood mononuclear cell with application as an immunostimulating and emulsifying compound.

Rhizobia exopolysaccharides: promising biopolymers for use in the formulation of plant inoculants

Inoculants with beneficial microorganisms comprise both selected strains and carriers that ensure a favorable microenvironment for cell survival and stability. Formulations of inoculants using synthetic polymers as carriers are common. However, only a few studies are available in the literature regarding the formulation of inoculants using natural biomolecules as carriers. Exopolysaccharides (EPS) are biomolecules produced by a vast array of microbial species, including symbiotic nitrogen-fixing bacteria, commonly known as rhizobia. EPS perform several functions, such as the protection against the deleterious effects of diverse environmental soil stresses. Two Rhizobium tropici strains and one Paraburkholderia strain were selected after semiquantitative analysis by scanning electron microscopy (SEM) of their EPS production in liquid YMA medium. Their EPS were characterized through a series of analytical techniques, aiming at their use in the formulation of plant inoculants. In addition, the effect of the carbon source on EPS yield was evaluated. Multi-stage fragmentation analysis showed the presence of xylose, glucose, galactose, galacturonic acid, and glucuronic acid in EPS chemical composition, which was confirmed by FT-IR spectra and 13C NMR spectroscopy. Thermal stability (thermogravimetric) was close to 270 °C and viscosity ranged from 120 to 1053.3 mPa.s. Surface morphology (SEM) was rough and irregular, with a cross-linked spongy matrix, which, together with the hydrophilic functional groups, confers water holding capacity. The present study showed that the three EPS have potential as microorganism carriers for formulation of microbial inoculants to be applied in plants.

Water-soluble amino functionalized chitosan: Preparation, characterization, antioxidant and antibacterial activities

Amino functionalized chitosan has attracted much attention because of the fascinated bioactivities. In our study, a novel water-soluble amino functionalized chitosan bearing free amino group at C-2 and quaternary ammonium moiety contained free amino group at C-6 (5c) was prepared by a four-step method. The structural characterization was identified by FTIR and ¹H NMR spectroscopy. The water-solubility and antioxidant activities against hydroxyl, DPPH radicals and reducing power were estimated. The results displayed that amino functionalized chitosan 5c exhibited improved water-solubility and antioxidant ability, especially its DPPH scavenging rate reached about 90 % at the minimum test concentration of 0.10 mg/mL. Besides, antibacterial tests showed that amino functional chitosan 5c had best antibacterial activities, which indicated that amino group made main contribution to the enhanced bioactivities. In short, the novel chitosan 5c possessed enhanced water-solubility and excellent antioxidant and antibacterial activities, which could provide novel strategy for the development of antioxidant and antibacterial agents in biomedicine and food fields.

Synergistic hepatoprotective effect of combined administration of Lachnum polysaccharide with silymarin

In recent years, combination therapy has gradually become one of the hot spots. As a new therapy strategy, we investigated the combination treatment of polysaccharide from Lachnum sp. (LEP-2b) with silymarin and compared the effects with mono-therapy. In this study, combining high-dose LEP-2b with silymarin (CH) significantly reduced serum biochemistry indexes (ALT, AST, AKP, LDH), hepatic inflammation (TNF-α, IL-6 and IL-1β) and improved the antioxidant status (SOD, CAT, GSH-Px, GSH, MDA and T-AOC), in which its effect on TNF-α was very significant (P < 0.001). Therefore, the expressions of related proteins in the JNK/p38 signaling pathway associated with TNF-α were examined. The result showed that CH treatment markedly increased the expression of p-p38 and inhibited the JNK phosphorylation. TUNEL staining, immunohistochemical staining and western blot assays demonstrated that the hepatoprotective effect of CH treatment was probably related with inhibiting hepatocyte apoptosis. In summary, combination of high dose LEP-2b with silymarin would be a more effective method to protect liver injury than mono-therapy.

Pentose-rich hydrolysate from oil palm empty fruit bunches for β-glucan production using Pichia jadinii and Cyberlindnera jadinii

Pentose-rich hydrolysate obtained from dilute acid pretreatment of oil palm empty fruit bunches was successfully consumed by pentose-consuming yeasts: Cyberlindnera jadinii (Cj) and Pichia jadinii (Pj). Nitrogen supplementation and no additional detoxification step were required. Pj produced 5.87 g/L of biomass using a C/N ratio of 14 after 120 h of fermentation, with xylose consumption of 71%. Cj produced 10.50 g/L of biomass after 96 h of fermentation with C/N ratio of 11.5, with maximum xylose consumption of 85%. β-glucans, high value-added macromolecules, were further extracted from the yeast biomass, achieving yields of 3.1 and 3.0% from Pj and Cj, respectively. The isolated polysaccharides showed a chemical structure of β-(1,3)-glucan with residues of other molecules. Additionally, β-(1,6) branches seems to have been broken during isolation process. Further studies assessing β-glucans production at industrial scale should be carried out looking for nitrogen sources and optimizing the β-glucan isolation method.

Protective effect of Lachnum polysaccharide on dextran sulfate sodium-induced colitis in mice

Inflammatory bowel disease (IBD) has been gradually considered as a public health challenge worldwide. This study determined the protective effect of Lachnum polysaccharide (LEP) on dextran sulfate sodium (DSS)-induced experimental colitis in mice and explored the underlying mechanism. Results showed that dietary LEP reduced DSS-induced disease activity index (DAI), colon shortening and colonic tissue damage. LEP treatment restored intestinal barrier integrity by regulating the expression of tight junction proteins and mucus layer protecting proteins. Moreover, pro-inflammatory cytokine production was inhibited by LEP through regulating PPARγ/NF-κB and IL-6/STAT3 pathways and inhibiting inflammatory cell infiltration. In addition, LEP also inhibited (NOD)-like receptor family pyrin domain containing 3 (NLRP3) inflammasome activation, endoplasmic reticulum (ER) stress and oxidative/nitrosative stress induced by DSS. These results provided a scientific basis for LEP as a potential natural agent for protecting mice from DSS-induced IBD.

Lachnum polysaccharide suppresses S180 sarcoma by boosting anti-tumor immune responses and skewing tumor-associated macrophages toward M1 phenotype

Therapeutic strategies that targeting tumor-associated macrophages (TAMs) reprogramming play a crucial role in ameliorating the immunosuppressive tumor microenvironment and boosting anti-tumor immune responses. In this study, we demonstrated that Lachnum polysaccharide (LEP) could work as an immunomodulator to reset TAMs from pro-tumor M2 to anti-tumor M1 phenotype. Mechanistically, LEP promoted Th1 polarization and the secretion of IFN-γ, which played a key role in M1 phenotype polarization. In parallel, LEP might directly activate M1 macrophages via TLR4 mediated NF-κB signaling pathway. Moreover, LEP also resulted in the accumulation of anti-tumor immune cells and decreased the infiltration of immunosuppressive cells such as myeloid-derived suppressor cells (MDSCs) and Treg cells, thereby potentiating anti-tumor immunity. In summary, these results revealed a novel mechanism of the anti-tumor effect of LEP and provided a potential new avenue targeting TAMs and cancer immunotherapy.

Dendrobium sonia polysaccharide regulates immunity and restores the dysbiosis of the gut microbiota of the cyclophosphamide-induced immunosuppressed mice

To recognize the potential medicinal value of the Dendrobium sonia, polysaccharide (DSP) was extracted, purified, and investigated for its immunomodulatory activity. In vitro, DSP was shown to enhance the viability (MTT assay) and phagocytosis of macrophages. In cyclophosphamide-induced immunosuppressed mice, DSP increased serum levels of TNF-α, IL-6 and IFN-γ (enzyme-linked immunosorbent assay, ELISA), and ameliorated the imbalance of the community of gut microbiota as detected by 16S ribosomal RNA gene sequencing. These results suggest that DSP might be beneficial for patients under immunosuppressed conditions.

Mechanism of bioactive polysaccharide from Lachnum sp. acts synergistically with 5-fluorouracil against human hepatocellular carcinoma

The antimetabolite 5-fluorouracil (5-FU) is a widely used antitumor agent, however the overall response rate to 5-FU as a single agent is usually limited. Herein, how Lachnum expolysaccharide (LEP-2a), a type of active polysaccharide isolated from Lachnum sp., acted synergistically with 5-FU on HepG2 cells was investigated. It was found that LEP-2a notably enhanced 5-FU sensitivity in HepG2 cells in a synergistic manner. After combination treatment of 5-FU and LEP-2a, Ras/Raf/MEK/ERK and PI3K/AKT/mTOR pathway were inactivated. In addition, combination treatment induced generation of reactive oxygen species, decreased the levels of intracellular antioxidant enzymes and triggered mitochondrial apoptosis pathway. Furthermore, 5-FU combined with LEP-2a also resulted in p53 activation and NF-κB inhibition, and cell cycle arrest in the S phase as well as cell metastasis stagnation. Interestingly, LEP-2a treatment also blocked the DNA damage repair procedure. These findings demonstrate that LEP-2a enhanced 5-FU sensitivity and combination of 5-FU and LEP-2a exerts synergistic antitumor efficiency through multiple approaches.

Physicochemical properties, immunostimulatory activity of the Lachnum polysaccharide and polysaccharide-dipeptide conjugates

The physicochemical properties and the immunoregulatory actions in vitro of an exopolysaccharide from Lachnum (LEP) and its conjugation with a dipeptide (LEP-RH) were investigated aiming to improve their functional characteristics. The structure characteristic of the LEP and LEP-RH were determined via FT-IR and NMR. The physicochemical properties were evaluated by scanning electron microscopy (SEM), rheometer, and differential scanning calorimeter (DSC). SEM results showed that LEP-RH had a rough surface and relatively loose distribution that different from LEP. Rheological studies of LEP and LEP-RH at the same concentration indicated that LEP and LEP-RH have similar shear-thinning behaviors and gel-like structures, while LEP-RH has a better thermal stability than LEP. Bioassay results showed that treatment with the higher dosage (200 μg/mL) of LEP and LEP-RH stimulated the proliferation, cytokine secretion (IL-2, IL-6 and TNF-α) of RAW264.7 macrophages.

Synergistic antitumor effect of polysaccharide from Lachnum sp. in combination with cyclophosphamide in hepatocellular carcinoma

Combination therapy with chemotherapeutics is attracting increasing attention as an important treatment option for hepatocellular carcinoma (HCC) due to its complex pathological characteristics. In this study, as a new therapy strategy, combination treatment of LEP-2a (a non-toxic polysaccharide from Lachnum sp.) with cyclophosphamide (CTX) was investigated. Results showed that combination treatment with LEP-2a and CTX processed a significantly synergistic anti-tumor effect in H22 tumor-bearing mice through Fas/FasL mediated caspase-dependent death pathway and mitochondria apoptosis pathway. Moreover, our study indicated that LEP-2a played a crucial role in enhancement of immune response, inhibition of tumor angiogenesis and down-regulation of survival associated proteins. Notably, side effects induced by CTX were relieved after LEP-2a treatment. These results support the conception that LEP-2a has the potential as an ideal adjuvant agent for a more effective combination therapy with CTX against HCC.