Preparation of a glucan from the roots of Rubus crataegifolius Bge. and its immunological activity

Optimization of enzyme-assisted microwave extraction, structural characterization, antioxidant activity and in vitro protective effect against H2O2-induced damage in HepG2 cells of polysaccharides from roots of Rubus crataegifolius Bunge

In this study, an enzyme-assisted microwave extraction process was obtained by response surface method of polysaccharide from roots of Rubus crataegifolius Bunge. The optimized extraction process was as follow: enzyme dosage 2 %, enzymatic time was 3.6 h, enzymatic pH 4.9, and microwave time 4.7 min, with the extraction yield of 9.07 %. Four homogeneous polysaccharides (RCP-1, RCP-3, RCP-4 and RCP-5) were purified through column chromatography. Four polysaccharides have the relative higher molecular weights of 1.70 × 106 Da, 5.56 × 106 Da, 4.97 × 106 Da, and 9.80 × 106 Da and mainly consisted of GluN, GluA, Glu, Gal and Arab. FT-IR and NMR spectral analysis confirmed that the purified polysaccharides were polypyranose containing α- and β-glycosidic bonds. RCP - 1 has a relative high crystallinity. Four purified polysaccharides contained triple helical conformations, and have good antioxidant activities. Among the purified polysaccharides, RCP - 1 was found to reduce the oxidative cell damage induced by H2O2 through increasing of cell viability, inhibition of AST and ALT levels, ROS production and cell apoptosis, increasing of the activities of antioxidative enzymes, as well as reduction of MDA content. Our findings would provide a foundation for purified polysaccharides efficient extraction and demonstrated that the polysaccharides from R. crataegifolius roots could be a promising hepatoprotective agent.

Isolation, structure characterization and in vitro immune-enhancing activity of a glucan from the peels of stem lettuce (Lactuca sativa)

BACKGROUND

Stem lettuce is a medicinal and edible plant. The peels, accounting for 300-400 g kg-1 raw stem lettuce and containing polysaccharides 200 g kg-1 , are discarded as industrial waste, causing environment pollution and resource waste.

RESULTS

A polysaccharide named PPSL10-2 was obtained from the peels of stem lettuce after hot water extraction, and gradation with cascade ultrafiltration and purification using DEAE-Sepharose cellulose. The purity and molecular weight of PPSL10-2 is 96.10% and 2.2 × 104  Da respectively, as detected by high-performance gel permeation chromatography. PPSL10-2 was found to be an α-(1→4)-d-glucan that branched at O-6 with a terminal 1-linked α-d-Glcp as side chain, and devoid of helix conformation, which was characterized by monosaccharide composition analysis, Fourier-transform infrared spectroscopy, Congo red test, scanning electron microscopy, methylation analysis and NMR spectroscopy. Furthermore, PPSL10-2 exhibited potent immune-enhancing effect by improving proliferation and phagocytosis, promoting the secretion of nitric oxide and cytokines, as well as the expression of related genes in RAW264.7 macrophages.

CONCLUSION

The findings of the present study suggest that peels as an agricultural by-product of stem lettuce are good sources of polysaccharides, which could be developed as immunopotentiator for improving human health. © 2023 Society of Chemical Industry.

Purification, characterization and anti-atherosclerotic effects of the polysaccharides from the fruiting body of Cordyceps militaris

Hyperlipidemia is one major cause of atherosclerosis, which is a basic pathological change of cardiovascular diseases. Polysaccharide is a water-soluble component with lipid-lowering effects. In this study, alkaline-extracted polysaccharides were obtained from the fruiting body of C. militaris. Polysaccharides were purified via anion exchange and size exclusion chromatography. Their structural characteristics were investigated via chemical and spectroscopic methods. CM3I was mainly composed of →4)α-D-Glcp(1 → glycosyls and differed from starch due to the presence of →4,6)β-D-Glcp(1 → glycosyls. CM3II was characterized by its backbone, which was composed of →4)-β-D-Manp(1 → 6)-α-D-Manp(1 → 6)-β-D-Manp(1 → linked glycosyls, and especially the presence of O-methyl. Moreover, CM3II exhibited powerful anti-atherosclerotic effects via lowering plasma lipid levels in apolipoprotein E-deficient mice. The underlying mechanisms were attributed to its promoting effect on LXRα and inhibitory effect on SREBP-2. Collectively, CM3I and CM3II are different from the previously reported polysaccharides from C. militaris, and CM3II has a potential application in hypolipidemia and anti-atherosclerosis.

Purification, structural characterization, and PCSK9 secretion inhibitory effect of the novel alkali-extracted polysaccharide from Cordyceps militaris

One novel alkali-extracted polysaccharide, CM3-SII, was obtained from the fruiting body of C. militaris via column chromatography. Its structural characteristics were investigated via chemical and spectroscopic methods. The backbone of CM3-SII was composed of →4)-β-D-Manp(1→, →6)-β-D-Manp(1→, and →6)-α-D-Manp(1→ glycosyls, and branching at the O-4 positions of →6)-β-D-Manp(1→ glycosyls with β-D-Galp, (1→2) linked-β-D-Galf, and →2,6)-α-D-Manp(1→ residues. Furthermore, O-6 and O-2 positions of the →2,6)-α-D-Manp(1→ residues were substituted with methyl and β-D-Galp, respectively. This polysaccharide significantly enhanced the intracellular protein expression of low-density lipoprotein receptor and proprotein convertase subtilisin/kexin type 9 (PCSK9) via regulating sterol regulatory element-binding protein 2 in hepatoma Huh7 cells. Of note, CM3-SII significantly decreased PCSK9 secretion at the concentration of 200 μg/mL. Collectively, CM3-SII is different from the previously reported alkali-extracted polysaccharides isolated from the fruiting body of C. militaris, and it may have potential application in hypolipidemia or as a pharmaceutical additive.

Immunostimulating effect of polysaccharides isolated from Ma-Nuo-Xi decoction in cyclophosphamide-immunosuppressed mice

Ma-Nuo-Xi Decoction (MNXD) is well-known in Tibetan medicine to be in line with the theory of treatment determination based on syndrome differentiation. However, the components responsible for its immunomodulating effect are unknown. In this study, three polysaccharide components-MNXD-P, MNXD-BD-P, and MNXD-AD-P-were isolated from MNXD and its basic and auxiliary prescription decoctions, of which MNXD-BD-P is composed of β-(1,4)-d-glucan and RG-I pectin, MNXD-AD-P contains mainly α-(1,4)-d-glucan and some amount of arabinogalactan and/or arabinorhamnogalactan, and MNXD-P contains components of both MNXD-BD-P and MNXD-AD-P. And treatment with these polysaccharides could significantly improve the host's specific and non-specific immunity, including cellular and humoral immunities, as well as promote recovery from myelosuppression in cyclophosphamide (CTX)-immunosuppressed mice. To our knowledge, this is the first report on chemical and immunoactivity study on polysaccharides from traditional Tibetan medicine compounds, which may provide a new idea for development of carbohydrate drugs from them.

Purification, characterization, and antitumor activity of a novel glucan from the fruiting bodies of Coriolus Versicolor

Cancer is one of the most common causes of deaths worldwide. Herein, we report an efficient natural anticancer glucan (CVG) extracted from Coriolus Versicolar (CV). CVG was extracted by the hot water extraction method followed by ethanol precipitation and purified using gas exclusion chromatography. Structural analysis revealed that CVG has a linear α-glucan chain composed of only (1→ 6)-α-D-Glcp. The antitumor activity of CVG on Sarcoma-180 cells was investigated in vitro and in vivo. Mice were treated with three doses of CVG (40, 100, 200 mg/kg body weight) for 9 days. Tumor weight, relative spleen, thymus weight, and lymphocyte proliferation were studied. A significant increase (P< 0.01) in relative spleen and thymus weight and a decrease (P< 0.01) in tumor weight at the doses of 100 and 200 mg/kg were observed. The results obtained demonstrate CVG has antitumor activity towards Sarcoma-180 cells by its immunomodulation activity.

In vivo anticancer and immunomodulating activities of mannogalactoglucan-type polysaccharides from Lentinus edodes (Berkeley) Singer

There is considerable interest in the potential of mushrooms in modulating the immune system and/or suppressing tumor growth. Among the studied bioactive compounds in mushrooms, polysaccharides are the most important. Nontoxic fungal polysaccharides have a more important role in immunomodulating and antitumor activities which are related to their effects to act of immune effecter cells such as lymphocytes, macrophages, dendritic cells, and natural killer cells involved in the innate and adaptive immunity. Two mannogalactoglucan-type polysaccharides (WPLE-N-2 and WPLE-A0.5-2), purified from the fruiting bodies of Lentinus edodes, were evaluated for their effects on the cellular immune response of Sarcoma 180 (S-180)-bearing mice. Mice were treated with 100 mg/kg body weight of the polysaccharides for 10 days. Significant tumor regressions of the polysaccharide groups' mice were observed compared to the control group. These polysaccharides could induce an increase in nitrite oxide (NO) production in peritoneal macrophages, significantly increase macrophage phagocytosis of tumor-bearing mice and augment concanavalin (ConA) and lipopolysaccharide (LPS)-induced splenocytes proliferation. Our results indicated that immunomodulating activity occurred through host mediation in response to lymphocyte proliferation, macrophage phagocytosis and induction of NO production while the antitumor activity occurred through direct cytotoxicity. Our findings suggest that mannogalactoglucan-type polysaccharides from L. edodes can be explored as novel potential immunostimulants. Our research provides essential data to a better understanding of L. edodes bioactive compounds, especially polysaccharides. Our results also confirm the key role of β-linkages in the antitumor and immunomodulating effects of polysaccharides.

Anti-hyperglycemic and anti-oxidative activities of ginseng polysaccharides in STZ-induced diabetic mice

Neutral (WGPN) and acidic (WGPA) polysaccharides were fractionated from ginseng polysaccharide. WGPN and WGPA decreased fasting blood glucose by different manners of administration. Intra-gastric administration of WGPA showed a marked hypoglycemic effect, which may be related to its anti-oxidative activity. The results indicated that WGPA may have anti-diabetic potential.

Anti-fatigue activity of polysaccharides from the fruits of four Tibetan plateau indigenous medicinal plants

ETHNOPHARMACOLOGICAL RELEVANCE

The fruits of Hippophae rhamnoides L., Lycium barbarum L., Lycium ruthenicum Murr. and Nitraria tangutorum Bobr. are traditional medicinal food of Tibetans and used to alleviate fatigue caused by oxygen deficiency for thousands of years. The present study focused on exploiting natural polysaccharides with remarkable anti-fatigue activity from the four Qinghai-Tibet plateau characteristic berries.

MATERIALS AND METHODS

The fruits of Hippophae rhamnoides, Lycium barbarum, Lycium ruthenicum and Nitraria tangutorum were collected from Haixi national municipality of Mongol and Tibetan (N 36.32°, E98.11°; altitude: 3100 m), Qinghai, China. Their polysaccharides (HRWP, LBWP, LRWP and NTWP) were isolated by hot-water extraction, and purified by DEAE-Cellulose ion-exchange chromatography. The total carbohydrate, uronic acid, protein and starch contents of polysaccharides were determined by a spectrophotometric method. The molecular weight distributions of polysaccharides were determined by gel filtration chromatography. Their monosaccharide composition analysis was performed by the method of 1-phenyl-3-methyl-5-pyrazolone (PMP) pre-column derivatization and RP-HPLC analysis. HRWP, LBWP, LRWP and NTWP (50, 100 and 200 mg/kg) were orally administrated to mice once daily for 15 days, respectively. Anti-fatigue activity was assessed using the forced swim test (FST), and serum biochemical parameters were determined by an autoanalyzer and commercially available kits; the body and organs were also weighted.

RESULT

LBWP, LRWP and NTWP were mainly composed of glucans and some RG-I pectins, and HRWP was mainly composed of HG-type pectin and some glucans. All the four polysaccharides decreased immobility in the FST, and the effects of LBWP and NTWP were demonstrated in lower doses compared with HRWP and LRWP. There was no significant difference in liver and heart indices between non-treated and polysaccharide-treated mice, but the spleen indices were increased in LBWP and NTWP (200mg/kg) group. Moreover, the FST-induced reduction in glucose (Glc), superoxide dismutase (SOD) and glutathione peroxidase (GPx) and increase in creatine phosphokinase (CK), lactic dehydrogenase (LDH), blood urea nitrogen (BUN), triglyceride (TG) and malondialdehyde (MDA) levels, all indicators of fatigue, were inhibited by HRWP, LBWP, LRWP and NTWP to a certain extent while the effects of LBWP and NTWP were much better than that of HRWP and LRWP at the same dosage.

CONCLUSION

Water-soluble polysaccharides HRWP, LBWP, LRWP and NTWP, from the fruits of four Tibetan plateau indigenous berry plants, significantly exhibited anti-fatigue activities for the first time, through triglyceride (TG) (or fat) mobilization during exercise and protecting corpuscular membrane by prevention of lipid oxidation via modifying several enzyme activities. Moreover, it is demonstrated that LBWP and NTWP are more potent than HRWP and LRWP, which were proposed to be applied in functional foods for anti-fatigue and antioxidant potential.

Structure analysis and antimutagenic activity of a novel salt-soluble polysaccharide from Auricularia polytricha

BACKGROUND

Auricularia polytricha is known to be a highly nutritious foodstuff. We report here the purification, structure characterization and antimutagenic activity in vivo of a 0.9% NaCl solution-soluble polysaccharide (SSP) from the mycelia of A. polytricha.

RESULTS

Analysis by high-performance liquid chromatography coupled to a TSK-G5000PWXL column and gel filtration chromatography on Sephacryl S-400 HR indicated that SSP is homogeneous with an average molecular weight of about 9.30 × 10(5) Da. The structure of SSP was revealed by chemical methods, Fourier transform infrared spectroscopy and nuclear magnetic resonance spectroscopy. Results indicated that SSP is a glucan consisting of a1,3-β-glucan, 1,6-α-glucan, 1,4-α-glucan and 1,3-α-glucan backbone with a single 1,6-α-d-glucopyranosyl side-branching unit on every nine residues, on average, along the main chain. Atomic force microscopy indicates the presence of macromolecular species in morphology and shows a clear association of prolate particle. Meanwhile, SSP was found to significantly preventing micronuclei in polychromatic erythrocytes and reticulocytes of mice (P < 0.01).

CONCLUSION

These results indicate that polysaccharide SSP from A. polytricha exhibits antimutagenic activity against the in vivo DNA-damaging effect of the indirectly acting alkylating agent cyclophosphamide.

Preparation of a Novel Glucuronomannan from Auricularia Auricala and its Immunological Activity

A glucuronomannan (AA-4-H, Mw around 4 KDa) was prepared from the fruit bodies of Auricularia auricala by extraction with hot water, deproteination by Sevag reagent, stepwise precipitation with ethanol and partial acid hydrolysis. Monosaccharides analysis revealed that AA-4-H consisted of 91% mannose (Man) and 9% glucuronic acid (GlcA). FT-IR, NMR and methylation analyses indicated that AA-4-H is a branched glucuronomannan. Its main chains are composed of 1, 3-linked α-Man p, side chains are single α-Man p or α-GlcA residues attached to the O-2 and O-6 of Man residues of the main chains. Bioassay indicated that AA-4-H remarkably enhanced B lymphocyte proliferation and increased the production of nitric oxide of macrophages in vitro. Thus, glucuronomannan AA-4-H could be explored as a potential immunostimulation agent.

Protective effects of salecan against carbon tetrachloride-induced acute liver injury in mice

Carbon tetrachloride (CCl₄) is a well-established model for screening hepato-protective drugs. The aim of the present study was to evaluate the potential protective effects of a novel soluble β-glucan salecan on acute liver injury induced by CCl₄ in mice and to further explore the underlying mechanisms. Mice were given salecan (40 mg kg⁻¹) or phosphate-buffered saline for 3 days prior to treatment with a single intraperitoneal dose of CCl₄ (1 ml kg⁻¹ body weight). Animals were sacrificed at 0, 12, 24, 48, 72 and 96 h post-injection of CCl₄. Serum liver enzyme levels, histology, lipid peroxidation, glutathione (GSH) content, expression of antioxidant enzymes and hepatocyte proliferation were subsequently evaluated. The serum levels of hepatic enzyme markers were markedly reduced in the salecan pretreatment group compared with the control group. Histopathological examination of the livers revealed that hepatocellular degeneration and necrosis were significantly attenuated at an early stage during CCl₄ intoxication and liver recovery was markedly accelerated at a later stage in salecan pre-administered mice. Furthermore, salecan administration remarkably alleviated lipid peroxidation and restored GSH depletion. Meanwhile, the expression of antioxidant genes was significantly elevated in the salecan-treated group. Interestingly, the administration of salecan remarkably enhanced hepatocyte proliferation in the recovery phase after CCl₄ injection. Taken together, these results demonstrated that salecan exhibits a protective action on acute hepatic injury induced by CCl₄ through attenuating oxidative stress and accelerating hepatocyte regeneration.