The in vivo and in vitro study of polysaccharides from a two-herb formula on ulcerative colitis and potential mechanism of action

Ethnopharmacological relevance

Lycium barbarum and Astragalus membranaceus are two traditional medicinal herbs widely used in China for nourishing Yin and reinforcing Qi. The purpose of the study was to investigate the prophylactic and curative effects of crude polysaccharides (QHPS) extracted from a two-herb formula composed of Lycium barbarum and Astragalus membranaceus at a ratio of 2:3 in colitis rats, and to further elucidate the potential mechanism of action in epithelial cell proliferation in vitro.

Materials and methods

An acetic acid (AA)-induced ulcerative colitis rat model was applied in the study. Two independent protocols were used to assess the prophylactic and curative effects of QHPS, respectively, in which rats were either pre-treated with QHPS (0.18 g/kg) for 14 days prior to AA induction, or post-treated with QHPS for 7 days after AA induction. The stool consistency and weight loss were used to evaluate disease activity. The morphological changes in intestinal mucosa at the end of the experiments were observed. The serum levels of endotoxin (EDT), diamine oxidase (DAO) and d-lactate (DLA), important biochemical markers for evaluating intestinal mucosal structure and function, were measured. In the in vitro mechanistic studies, rat intestinal epithelial cells (IEC-6) were used to access for epithelium regeneration.

Results

The intra-colonic instillation of AA induced ulcerative colitis in rat, as indicated by diarrhea, weight loss, and colonic mucosal damage. Both prophylactic and curative treatments effectively reduced the weight loss and diarrhea and attenuated the colonic mucosal damage associated with inducible colitis. The significant increase in serum levels of DAO, DLA and EDT was induced by AA and inhibited by QHPS treatment. Moreover, QHPS could significantly stimulate IEC-6 proliferation in a dose-dependent manner (p<0.05).

Conclusion

The present study indicated for the first time that polysaccharides extracted from this two-herb formula can protect against experimental ulcerative colitis, presumably by promoting the recovery of the intestinal barrier.     

NaCl胁迫下黑果枸杞bHLH转录因子家族鉴定与生物信息学分析

目的基于不同浓度NaCl胁迫下黑果枸Lyciumruthenicum杞转录组测序结果,利用生物信息学方法对黑果枸杞bHLH转录因子家族成员进行鉴定。方法通过对NaCl胁迫下黑果枸杞根和叶的样品进行转录组测序,筛选出bHLH家族基因,利用生物信息学方法对筛选到的基因进行理化性质、保守结构域、基因结构、细胞定位及系统进化分析。结果黑果枸杞在NaCl胁迫下的转录组数据库中共筛选出89个bHLH转录因子家族基因;bHLH家族蛋白理化性质差异较大,71.90%的蛋白质呈弱酸性,蛋白属于亲水蛋白。黑果枸杞bHLH家族蛋白含有2个保守结构域,分别位于N端的碱性氨基酸区和C端的螺旋-环-螺旋区。亚细胞定位预测bHLH家族蛋白主要分布在细胞核内和细胞质中。进化分析显示,黑果枸杞中89个bHLH转录因子家族蛋白可分为20个亚族,其中第3亚族中包含的bHLH成员最多,为11个;第7、11、13、22亚族中的成员数量均为1个,其他亚族为2～9个。结论 NaCl胁迫下黑果枸杞bHLH转录因子家族有89个成员,bHLH家族蛋白大多数呈弱酸性,属亲水蛋白,可分为20个亚族。     

Macrophages, rather than T and B cells are principal immunostimulatory target cells of Lycium barbarum L. polysaccharide LBPF4-OL

Aim of the study

Lycium barbarum L. is a renowned Yin strengthening agent in traditional Chinese medicine. Lycium barbarum L. polysaccharide-protein complex is well-known for its immunoregulatory and antitumor effects. LBPF4-OL is the glycan part of Lycium barbarum L. polysaccharide-protein complex fraction 4 (LBPF4). LBPF4-OL's active contribution in LBPF4 is still blank. In the study, we enrich the polysaccharide part of Lycium barbarum L. polysaccharide-protein complex, and investigate its immunostimulatory effects on mouse spleen cells, T cells, B cells and macrophages.

Materials and methods

Balb/C mice were used in vitro and in vivo studies. In in vitro study, lymphocyte proliferations were analyzed with ³H-TdR incorporation method. Miltenyi MicroBeads were used in the purification of lymphocytes. Activation of T and B cells was analyzed by flow cytometry. In order to obtain the peritoneal macrophages, mice were injected i.p. with 1 mL of sodium thioglycollate 3 days prior to killing. Spleen cells were stimulated with LBPF4-OL and cytokine concentrations in the supernatants were determined by multiplex bead analysis. In in vivo study, mice were injected i.p. with 1 mL of normal saline or 100 μg/mL LBPF4-OL daily for 6 days. Peritoneal macrophage functions were analyzed by enzyme-linked immunosorbent assay and flow cytometry assay.

Results

Spleen cells and lymphocyte proliferation assay indicated that LBPF4-OL markedly induced the spleen cell proliferation, but could not induce proliferation of purified T and B lymphocytes. Further research revealed that B cell proliferation took place in the presence of activated macrophages or LPS. Multiplex bead analysis showed that LBPF4-OL can obviously induce IL-6, IL-8, IL-10 and TNF-α production of the spleen cells in a concentration-dependent manner. Flow cytometric analysis showed that LBPF4-OL (i.p.) prompts CD86 and MHC-II molecules expression on macrophages. ELISA assay showed that LBPF4-OL can greatly strengthen macrophage releasing of TNF-α and IL-1β.

Conclusion

These results suggested that glycan LBPF4-OL plays an important role in the immunopharmacological activity of Lycium barbarum L. polysaccharide-protein complex, and primary mouse macrophages, rather than T and B cells, are the principal target cells of it.     

The in vitro antiviral property of Azadirachta indica polysaccharides for poliovirus

Ethnopharmacological relevance

Azadirachta indica A. Juss, popularly known as neem, has been extensively used in Ayurvedic medicine by Indian population for over 2000 years. It is used traditionally for the healing of various diseases. Natural products and their derivatives provide an excellent source for new anti-viral drugs.

Aim of the study

The present study aims at evaluating the activity of two polysaccharides (P1 and P2) isolated from the leaves of Azadirachta indica and their chemical sulfated derivatives (P1S and P2S) against poliovirus type 1 (PV-1).

Materials and methods

The cytotoxicity of the compounds was analyzed by MTT and the antiviral effect was determined by plaque reduction assay in different protocols.

Results

The polysaccharides did not show any cytotoxic effects on HEp-2 cells at the highest tested concentration (200 μg/ml) and exhibited significant antiviral activity with inhibitory concentrations (IC₅₀) of 80 μg/ml, 37.5 μg/ml, 77.5 μg/ml, and 12.1 μg/ml for P1, P1S, P2 and P2S, respectively, and the selectivity indexes (SI) ranged from 18 to 131.9. The compounds demonstrated better inhibitory effect when added concomitantly with the virus infection with a dose-dependent curve inhibition. Lesser effect was observed when the compounds were added after viral infection and the least effect at pre-treatment.

Conclusions

We suggested that the polysaccharides obtained from Azadirachta indica act against PV-1 by inhibiting the initial stage of viral replication. Importantly, original polysaccharides showed better virucidal effect than their sulfated derivatives at all tested concentrations. This study provides a scientific basis for the past and present ethnomedical uses of this plant.     

Lycium barbarum polysaccharides protect mice liver from carbon tetrachloride-induced oxidative stress and necroinflammation

Ethnopharmacological relevance

Lycium barbarum has been used as a traditional Chinese medicine to nourish liver, kidneys and the eyes.

Aim of the study

We investigated the protective mechanisms of Wolfberry, Lycium barbarum polysaccharides (LBP) in carbon tetrachloride (CCl₄)-induced acute liver injury.

Materials and methods

Mice were intraperitoneally injected with a 50 μl/kg CCl₄ to induce acute hepatotoxicity (8 h) and were orally fed with LBP 2 h before the CCl₄ injection. There were six experimental groups of mice (n = 7-8 per group), namely: control mice (vehicle only; 1 mg/kg LBP or 10 mg/kg LBP), CCl₄-treated mice and CCl₄ + LBP treated mice (1 mg/kg LBP or 10 mg/kg LBP).

Results

Pre-treatment with LBP effectively reduced the hepatic necrosis and the serum ALT level induced by CCl₄ intoxication. LBP remarkably inhibited cytochrome P450 2E1 expression and restored the expression levels of antioxidant enzymes. It also decreased the level of nitric oxide metabolism and lipid peroxidation induced by CCl₄. LBP attenuated hepatic inflammation via down-regulation of proinflammatory mediators and chemokines. Furthermore, LBP promoted liver regeneration after CCl₄ treatment. The protective effects of LBP against hepatotoxicity were partly through the down-regulation of nuclear factor kappa-B activity.

Conclusion

LBP is effective in reducing necroinflammation and oxidative stress induced by a chemical toxin, thus it has a great potential use as a food supplement in the prevention of hepatic diseases.     

Purified active lotus plumule (Nelumbo nucifera Gaertn) polysaccharides exert anti-inflammatory activity through decreasing Toll-like receptor-2 and -4 expressions using mouse primary splenocytes

Ethnopharmacological significance

Lotus plumule is widely used as traditional Chinese medicine. Among the active components in lotus plumule, polysaccharides exhibit promising potential for its potent anti-inflammatory effects. However, the anti-inflammatory mechanism of purified polysaccharides from lotus plumule remains unknown.To evaluate their anti-inflammatory potential and possible mechanisms of purified polysaccharides in lotus plumule, two active lotus plumule polysaccharides, fractions F1 and F2, were subjected to assay their anti-inflammatory potential and possible mechanisms using murine primary splenocytes in the absence or presence of lipopolysaccharide (LPS).

Materials and methods

Two purified active lotus plumule polysaccharides, F1 and F2, were cultured independently with murine primary splenocytes in the absence or presence of LPS under four different experiment models in vitro. Changes in pro-inflammatory IL-1β, IL-6 and TNF-α, as well as anti-inflammatory IL-10 cytokines secreted by the treated splenocytes were determined using an enzyme-linked immunosorbent assay (ELISA). The amount of Toll-like receptor (TLR)-2 and TLR-4 mRNA expression levels in the cells were quantitated using a two-step real-time polymerase chain reaction (PCR) assay.

Results

The results showed that F1 and F2 treatments alone, particularly F2, significantly (P<0.05) decreased pro-/anti-inflammatory (IL-1β/IL-10 and TNF-α/IL-10) cytokine secretion ratios dose-dependently. F1 and F2 treatments in the presence of LPS significantly decreased TLR-2 and/or TLR-4 mRNA expression levels in the splenocytes under inflammatory and repair experiment models.

Conclusions

The present study proved that F1 and F2 had strong anti-inflammatory effects through inhibiting TLR-2 and/or TLR-4 expressions in the splenocytes in normal, inflammatory and repair situations. Our results further suggest that F2, which is a glycoprotein with low molecular weight of 25.7 kDa, may serve as a promising lead for the development of selective TLR antagonistic agents for inflammatory diseases.     

Macrophage activating activity of pyrrole alkaloids from Morus alba fruits

Ethnopharmacological relevance

The fruits of Morus alba have been traditionally used as a tonic to enhance immune responses.

Materials and methods

The macrophage activating constituents of Morus alba fruits were purified using various column chromatography techniques. The structures of isolated compounds were determined on the basis of spectroscopic data interpretation such as 1D and 2D NMR analysis. The macrophage activating activities of isolated compounds were evaluated by measuring the production of nitric oxide, TNF-α and IL-12 in RAW 264.7 cells. The phagocytic activity was also evaluated.

Results

Five pyrrole alkaloids, 5-(hydroxymethyl)-1H-pyrrole-2-carboxaldehyde (1), 2-formyl-1H-pyrrole-1-butanoic acid (2), 2-formyl-5-(hydroxymethyl)-1H-pyrrole-1-butanoic acid (3), 2-formyl-5-(methoxymethyl)-1H-pyrrole-1-butanoic acid (4) and Morrole A (5) were isolated from the fruits of Morus alba. Morrole A (5) is first reported in nature and other pyrrole alkaloids (1–4) are first reported from Morus species. Among the isolated compounds, compounds 3 and 4 significantly activated macrophage activity by the enhancement of nitric oxide, TNF-α and IL-12 production, and the stimulation of phagocytic activity in RAW 264.7 cells.

Conclusion

Pyrrole alkaloids, including a new compound, were isolated from Morus alba fruits. These compounds activated macrophage activity in RAW 264.7 cells.     

Cytoprotective effect of the fruits of Lycium chinense Miller against oxidative stress-induced hepatotoxicity

Aim of the study

Fruits of Lycium chinense Miller (Solanaceae), distributed in northeast Asia, have gained attraction for their hepatoprotective role in traditional oriental medicine.The excessive production of reactive oxygen species (ROS) is hazardous for living organisms and damage major cellular constituents such as DNA, lipid, and protein. The cytoprotective effect of Lycium chinense fruits (Lycium extract) was assessed against H₂O₂-induced Chang liver cell damage.

Materials and methods

The effect of Lycium extract against H₂O₂-induced cell death was determined by the MTT assay. Radical scavenging activity was determined through the assessments of 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals, intracellular ROS, hydroxyl radicals, and superoxide. The inductions of antioxidant enzymes were determined via their protein expressions and activities. DNA damage was measured using comet assay and expression of phospho-histone H2A.X. Lipid peroxidation was measured using 8-isoprostane level and fluorescent probe. Protein modification was measured using protein carbonyl moiety.

Results and conclusion

Lycium extract scavenged the DPPH free radicals, intracellular ROS, hydroxyl radicals, and superoxide. Lycium extract recovered activities of catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) decreased by H₂O₂. Lycium extract decreased DNA damage, lipid peroxidation and protein carbonyl values increased by H₂O₂ exposure. In addition, Lycium extract increased the cell viability of Chang liver cells exposed to H₂O₂ via inhibition of apoptosis. These results show that Lycium extract protected Chang liver cells against oxidative stressed cell damage by H₂O₂ via scavenging ROS and enhancing antioxidant enzyme activity.     

Antitumor and immunomodulatory activity of polysaccharides from the roots of Actinidia eriantha

Aim of the study

The roots of Actinidia eriantha Benth (Actinidiaceae) have been used for cancers in the Chinese folk medicine. The present study aimed at evaluating the antitumor potentials of the polysaccharides from the roots of Actinidia eriantha and elucidating their immunological mechanisms by determining the effects on the growth of tumor transplanted in mice and the immune response in tumor-bearing mice.

Materials and methods

The total polysaccharide AEP and fours purified polysaccharides AEPA, AEPB, AEPC and AEPD were isolated and purified from the roots of Actinidia eriantha by hot water extraction, ethanol precipitation, dialysis and gel filtration. Their effects on the growth of mouse transplantable tumor, splenocyte proliferation, the activity of natural killer (NK) cells and cytotoxic T lymphocytes (CTL), production of cytokines from splenocytes, and serum antigen-specific antibody levels in tumor-bearing mice were measured.

Results

AEP and four purified polysaccharides could not only significantly inhibit the growth of mouse transplantable tumor, but also remarkably promote splenocytes proliferation, NK cell and CTL activity, IL-2 and IFN-γ production from splenocytes, and serum antigen-specific antibody levels in tumor-bearing mice.

Conclusions

The antitumor activity of AEP and four purified polysaccharides might be achieved by improving immune response, and the composition of the monosaccharides, uronic acid contents and molecular weight could affect their antitumor and immunomodulatory activity.