Water-soluble polysaccharides from Piper regnellii (Pariparoba) leaves: Structural characterization and antinociceptive and anti-inflammatory activities.

Piper regnellii is a plant popularly known as "Pariparoba" and it is widely used in folk medicine to treat pain, inflammation, among others. This work presents the extraction, purification and characterization of polysaccharides present in the plant leaves and evaluation of their anti-inflammatory and antinociceptive activities. From the crude aqueous extract of P. regnellii leaves, a polysaccharide fraction named PR30R, predominantly constituted of arabinose, galactose and galacturonic acid monosaccharide units, was obtained. Methylation and NMR analysis showed that the main polysaccharides of PR30R are a type II arabinogalactan, formed by a ß-D-Galp-(1 â†’ 3) main chain, substituted at O-6 by side chains of ß-D-Galp-(1 â†’ 6), which are substituted at O-3 by non-reducing α-L-Araf ends, and a homogalacturonan, formed by →4)-α-D-GalpA-(1→ units. Intraperitoneal administration of the crude polysaccharide fraction PRSF reduced significantly nociception induced by acetic acid in mice at the doses tested, and the PR30R fraction, derived from PRSF, presented antinociceptive and anti-inflammatory effects at a dose of 0.1096 mg/kg (PRSF ED50). These data support the use of the plant leaves in folk medicine as an herbal tea to treat pain and inflammation.

Local effects of natural alkylamides from Acmella oleracea and synthetic isobutylalkyl amide on neuropathic and postoperative pain models in mice.

Neuropathic and postoperative pain are clinical conditions that impair the patient's quality of life. The current pharmacotherapy of both painful states is ineffective and accompanied by several side effects. In order to develop new therapeutics targets, the secondary metabolites of plants have been extensively studied. Acmella oleracea ("jambu") is a native plant from the Amazon region and rich in alkylamides, bioactive compounds responsible for inducing anesthetic and chemesthetic sensations. We previously demonstrated that the intraplantar administration of an hexanic fraction (HF) rich in alkylamides from jambu and the synthetic isobutylalkyl amide (IBA) at 0.1 µg/20 µL can promote antinociceptive and anti-inflammatory effects. Thus, this study aimed to evaluate the local effect of HF and IBA (0.1 µg/20 µL) on neuropathic (partial sciatic nerve ligation, PSNL) and postoperative pain (plantar incision surgery, PIS) models in mice. Seven days after the PSNL, the mechanical (von Frey test) and cold (acetone-evoked evaporative cooling) allodynia, and digital gait parameters were analyzed. The intraplantar HF and IBA treatments attenuated the mechanical and cold allodynia as well as the static (max. Contact and print area) and dynamic (stand duration) parameters of digital gait analyses. On the day after PIS, the mechanical allodynia, heat hyperalgesia (hot plate, 52 ± 0.1°C), and spontaneous nociception scores were evaluated. Topical treatment with HF reduced the mechanical allodynia, heat hyperalgesia, and spontaneous nociception scores. In contrast, IBA treatment only partially reduced the mechanical allodynia. In summary, the local treatment with HF was effective on both neuropathic and postoperative pain, as opposed to IBA, which only had an effect on neuropathic pain.

Agaricus bisporus ß-(1 → 6)-d-glucan induces M1 phenotype on macrophages and increases sensitivity to doxorubicin of triple negative breast cancer cells.

Mushroom ß-d-glucans have demonstrated immunomodulatory activity, which is initiated by their recognition by specific receptors on immune system cells surfaces. Studies indicated that ß-d-glucans may present a synergistic effect with chemotherapy drugs. In this study, a linear ß-(1 â†’ 6)-d-glucan (B16), isolated from A. bisporus and previously characterized (Mw: 8.26 × 104 g/mol), was evaluated about its capacity to modulate THP-1 macrophages towards an M1 phenotype and induce an antitumoral activity. This was evidenced by the production of pro-inflammatory markers upon B16 treatment (30; 100 µg/mL). The breast tumor cells (MDA-MB-231) viability was not affected by treatment with B16, however, their viability markedly decreased upon treatment with the drug doxorubicin. The results showed a synergic effect of B16 and doxorubicin, which reduced the viability of MDA-MB-231 cells by 31%. Furthermore, B16 treatment provided a sustainable M1 state environment and contributed to increase the sensitivity of breast cancer cells to the doxorubicin treatment.

Effectiveness of the polyphenols-rich Sedum dendroideum infusion on gastric ulcer healing in rats: Roles of protective endogenous factors and antioxidant and anti-inflammatory mechanisms.

ETHNOPHARMACOLOGICAL RELEVANCE: Peptic ulcer is an inflammatory disease that therapeutic options are mainly focused in antisecretory drugs. Sedum dendroideum Moc & Sessé ex DC (Crassulaceae) is employed in folk medicine for the treatment of gastric ulcers. Recently, our group demonstrated that Sedum dendroideum infusion (SDI) is rich in polyphenols (flavonol glycosides, myricetin, quercetin and kaempferol) and promoted gastroprotection against acute ulcer models, without changes gastric acid secretion. AIM OF THE STUDY: Here, we follow the investigation of the healing effects of SDI (ED50 = 191 mg/kg) in the chronic gastric ulcer model induced by 80% acetic acid in rats, elucidating underlying mechanisms. MATERIAL AND METHODS: Rats were orally treated with vehicle (water, 1 mL/kg), SDI (191 mg/kg), omeprazole (40 mg/kg) or sucralfate (100 mg/kg) twice daily for 5 days after ulcer induction. Following treatments, toxicological effects, macroscopic ulcer appearance, microscopic histological (HE, mucin PAS-staining) and immunohistochemical (PCNA and HSP70) analysis, inflammatory (MPO and NAG activity, cytokine levels measurements) and antioxidant (SOD and CAT) parameters were investigated in gastric ulcer tissues. RESULTS: Oral treatment with SDI accelerated gastric ulcer healing, maintained mucin content and promoted epithelial cell proliferation. SDI also reduced neutrophil and mononuclear leukocyte infiltration, TNF-α and IL-1ß levels and the oxidative stress, restoring SOD and CAT activities in the ulcer tissue. CONCLUSIONS: The gastric healing effect of SDI was mediated through endogenous protective events as well as due to the anti-inflammatory and antioxidant actions. Our observations support and reinforce the traditional utilize of Sedum dendroideum as a natural nontoxic therapeutic alternative for the treatment of gastric ulcers.

Polysaccharide fractions from Handroanthus heptaphyllus and Handroanthus albus barks: Structural characterization and cytotoxic activity.

Barks of trees of the genus Handroanthus are known for their antitumor activity, which is attributed to naphthoquinones. Another class of molecules that has shown antitumor activity are the polysaccharides, however those from Handroanthus barks have never been studied. Accordingly, the aim of this study was to extract polysaccharides from H. heptaphyllus and H. albus barks, to characterize them structurally and to evaluate their cytotoxic effects on the human colon and human breast cancer cell lines, Caco-2 and MCF-7, respectively. The polysaccharides were extracted with boiling water and fractionated by freeze-thawing process. The soluble polysaccharide fractions HHBSF and HABSF were characterized by monosaccharide composition, methylation and NMR analyses, and their effects on proliferation of Caco-2 and MCF-7 cells were evaluated using MTT cell viability assay. HHBSF and HABSF were mainly constituted of galactoglucomannan, type II arabinogalactan (AGII) and type I rhamnogalacturonan (RGI), however, only HABSF significantly inhibited the growth of MCF-7 (CC50 = 327 µg/mL) and Caco-2 (CC50 = 2258 µg/mL) cells. Differences in the fine structure and proportion of their polysaccharides, and maybe in the composition of associated phenolic compounds could explain the different effects of HHBSF and HABSF.

A polysaccharide fraction from Handroanthus albus (yellow ipê) leaves with antinociceptive and anti-inflammatory activities.

Handroanthus albus, commonly known as yellow ipê, is a native and widely distributed tree in Brazil. An aqueous soluble polysaccharide fraction (HASP) was obtained from its leaves, and monosaccharide composition, glycosidic linkage analysis by methylation and NMR spectroscopy indicated that HASP is mainly composed of a type II arabinogalactan, and suggested that other polysaccharides could also be present in a smaller proportion. HASP was able to promote antinociception in formalin-induced (second phase) and on glutamate-induced nociception tests, besides reducing the number of abdominal contortions induced by acetic acid in mice. Moreover, HASP reduced acetic acid-induced leukocyte infiltration in the peritoneal cavity and showed anti-edematogenic activity, decreasing mechanical allodynia and myeloperoxidase activity in the carrageenan-induced paw edema model. These results showed that the polysaccharide fraction HASP from H. albus leaves has interesting antinociceptive and anti-inflammatory activities.

Pharmacological potential of alkylamides from Acmella oleracea flowers and synthetic isobutylalkyl amide to treat inflammatory pain.

Acmella oleracea ("jambu") is an Amazonian plant rich in alkylamides. Its flowers are widely used in folk medicine to treat toothache due to tingling, numbness, and local anaesthesia caused in the mouth. Our group previously demonstrated that the intraplantar (i.pl.) injection of an alkylamide-rich hexane fraction (HF) obtained from jambu flowers and a synthetic isobutylalkyl amide (IBA) displayed antinociceptive and anesthetic effects in acute pain models. Thus, here we evaluated the effects of HF and IBA on carrageenan-induced acute inflammation. Mice were pretreated with HF or IBA (0.01, 0.1, and 1 µg/20 µL, i.pl.) 15 min before carrageenan injection (300 µg/20 µL, i.pl.). Mechanical allodynia and paw oedema were evaluated previously (basal) and at 0.5 until 6 h following carrageenan. Both HF and IBA at 0.1 µg promoted effective and long-lasting antiallodynic and anti-oedematogenic activities until 3 and 5 h, respectively, in comparison to the different doses evaluated. At the inflammatory peak, the plantar surfaces were excised for measurement of inflammatory and oxidative stress parameters. HF and IBA (0.1 µg) reduced the myeloperoxidase activity, TNF-α and IL-1ß levels, prevented the production of lipid hydroperoxides, and the decrease of antioxidant agents, namely superoxide dismutase and catalase activities, and glutathione contents. Furthermore, only HF maintained IL-10 levels and decreased PGE2 synthesis. On the basis of the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, HF and IBA are devoid of antioxidant activity in vitro. Collectively, our results demonstrated the promising anti-inflammatory effect of local pretreatment with alkylamides, supporting the potential of these molecules to treat acute inflammatory pain conditions.

Anticoagulant and antithrombotic effects of chemically sulfated guar gum.

Heparin is an extremely important and recognized anticoagulant and antithrombotic agent. Obtained from animal sources and being highly potent, risks of contamination by pathogens and bleeding are some concerns related to heparin use. In the search for alternatives to heparin, several researches have been performed with chemically sulfated polysaccharides obtained from non-animal sources. In this work, studies with guar gum led to a partially hydrolyzed and chemically sulfated derivative (hGGSL) with Mw of 15.6 kDa, DS of 1.91 and promising anticoagulant and antithrombotic properties. In vitro, hGGSL was only 4.5× less potent than unfractionated heparin, acting mainly by inhibiting thrombin via antithrombin, and had its anticoagulant activity inhibited by protamine. In vivo, hGGSL showed potential for subcutaneous use and was effective in reducing venous thrombosis. Collectively, the results provide a basis for the development of a new anticoagulant and antithrombotic agent.

A polysaccharide fraction from "ipê-roxo" (Handroanthus heptaphyllus) leaves with gastroprotective activity.

A polysaccharide fraction from Handroanthus heptaphyllus leaves was obtained with a simple and quick purification method. Methylation analysis and NMR spectroscopy indicated the presence of a complex polysaccharide fraction mainly constituted by a type II arabinogalactan. This is the first report in literature on structural elucidation of polysaccharides of species from genus Handroanthus. Oral and intraperitoneal administration of the polysaccharide fraction from Handroanthus heptaphyllus (HHSF) protected the gastric mucosa in an acute model of gastric lesion induced by ethanol, preserving gastric mucus. Furthermore, in the indomethacin model, HHSF reduced wounded area and inhibited mucus and GSH depletion. HHSF also accelerated gastric ulcer healing, accompanied by the maintenance of GSH levels. In addition, in an oxidative stress model with human epithelial cell line (Caco-2), HHSF was able to preserve GSH levels and was not toxic to cells. Collectively, these results showed that HHSF has an interesting antiulcerogenic activity and could constitute an interesting option for the treatment of gastric ulcer.

Chemical composition, antioxidant and gastrointestinal properties of Sedum dendroideum Moc & Sessé ex DC leaves tea infusion.

ETHNOPHARMACOLOGICAL RELEVANCE: Sedum dendroideum Moc & Sessé ex DC (Crassulaceae) is a medicinal plant employed in Mexican and Brasilian folk medicine as juice or infusion, as remedy for the treatment of different diseases, including gastric disorders. AIM OF THE STUDY: Although some studies carried out with Sedum dendroideum have demonstrated its gastroprotective effect, the purpose of this study was to elucidate the chemical constituents, antioxidant, cytotoxic and mechanisms underlying the gastrointestinal properties of Sedum dendroideum accordingly its traditional use, as fresh leaves tea infusion (SDI). MATERIALS AND METHODS: Chemical constituents were analyzed using high performance liquid chromatography and mass spectrometry (HPLC-MS). Antioxidant and cytotoxicity were evaluated in in vitro assays. The efficacy of the SDI on macroscopic ulcer appearance, mucus and GSH maintenance on ethanol- and indomethacin-induced ulcer models, gastric acid secretion and gastrointestinal motility were investigated. RESULTS: Phytochemical analysis by HPLC-MS revealed the presence of different flavonol glycosides, containing myricetin and quercetin, along with the kaempferol as aglycones. In vitro pharmacological investigation of SDI demonstrated potent antioxidant activity in DPPH assay (IC50: 13.25 ±â€¯3.37 µg/mL) and absence of cytotoxicity in Caco-2 cells by MTT method. Oral administration of SDI (ED50 of 191.00 ±â€¯0.08 mg/kg) in rats promoted gastroprotection against ethanol or indomethacin in rats through reinforcement of gastric wall mucus, GSH content and nitric oxide release, without present antisecretory properties. The gastroprotective effect was maintained when SDI (19 mg/kg) was administrated by intraperitoneal route. Furthermore, SDI (150 mg/kg) unchanged the gastric emptying but increase small bowel transit in mice through cholinergic pathways. CONCLUSIONS: Collectively, this study confirmed that Sedum dendroideum promotes gastroprotection through preventing of endogenous defense mechanisms, represented by mucus and GSH without changes gastric acid secretion. Sedum dendroideum tea infusion features a chemical profile that contributes to the antioxidant and gastric health-promoting effects, supporting the use in folk medicine for the treatment of gastrointestinal disorders.

Distinct mechanisms underlying local antinociceptive and pronociceptive effects of natural alkylamides from Acmella oleracea compared to synthetic isobutylalkyl amide.

Acmella oleracea (jambu), is used as ingredient for food and in folk medicine to relief toothache. Jambu edible flowers are rich in alkylamides, mainly spilanthol, which are responsible to evoke chemesthetic sensations. This study aimed to investigate the local effects promoted by the intraplantar injection of the hexanic fraction (HF) rich in alkylamides from jambu flowers and compare to synthetic isobutylalkyl amide (IBA). Swiss male mice were intraplantarly administrated with HF and IBA (0.1-30 µg/20 µL), and the underlying mechanisms associated to the antinociceptive (0.1 µg) and pronociceptive (30 µg) effects were evaluated in chemical and sensorial tests. HF and IBA at 0.1 µg promoted analgesia in neurogenic and inflammatory phases of formalin test, against glutamate-induced nociception and independent of the activation of endogenous opioidergic system and dependent of TRPV1 modulation, whereas only HF reduced both nociception and mast cell degranulation in hindpaw induced by compound 48/80. However, both potentiated the TRPA1-mediated nociception. In contrast, HF and IBA (30 µg)-evoked nociceptive behaviors were reduced by the activation of opioidergic system, by TRPA1 antagonist and TRP nociceptive fibers desensitization. In addition, 30 µg IBA-evoked nociception by activation of TRPV1, and 30 µg HF by mast cell degranulation. Furthermore, on the contrary of IBA, HF elevated both mechanical and thermal paw threshold. Altogether, these results indicate that alkylamides could elicited dual effects, adding new evidences and mechanisms for these opposite actions in different doses. Although further research is needed, we confirmed that alkylamides displays local analgesic and/or anesthetic effects.

Rhamnogalacturonan, a chemically-defined polysaccharide, improves intestinal barrier function in DSS-induced colitis in mice and human Caco-2 cells.

Natural polysaccharides have emerged as an important class of bioactive compounds due their beneficial biological effects. Here we investigated the protective and healing effects of rhamnogalacturonan (RGal) isolated from Acmella oleracea (L.) R.K. Jansen leaves in an experimental model of intestinal inflammation in mice and in heterogeneous human epithelial colorectal adenocarcinoma cells (Caco-2). The findings demonstrated that RGal treatment for 7 days reduced the severity of DSS-induced colitis by protecting mice from weight loss, macroscopic damage and reduction of colon length. When compared to the DSS group, RGal also protected the colon epithelium and promoted the maintenance of mucosal enterocytes and mucus secreting goblet cells, in addition to conserving collagen homeostasis and increasing cell proliferation. In an in vitro barrier function assay, RGal reduced the cellular permeability after exposure to IL-1ß, while decreasing IL-8 secretion and claudin-1 expression and preserving the distribution of occludin. Furthermore, we also observed that RGal accelerated the wound healing in Caco-2 epithelial cell line. In conclusion, RGal ameliorates intestinal barrier function in vivo and in vitro and may represent an attractive and promising molecule for the therapeutic management of ulcerative colitis.

Gastroprotective activity of a pectic polysaccharide fraction obtained from infusion of Sedum dendroideum leaves.

BACKGROUND: Sedum dendroideum, popularly known in Brazil as balsam, is traditionally used as a wound healing agent, to treat gastritis, and several other health problems. Some studies have shown that plant polysaccharides may have gastroprotective properties. PURPOSE: Considering the popular use of S. dendroideum and the gastroprotective activity of polysaccharides, the objective of this work was to obtain, to characterize, and to evaluate the gastroprotective activity of a polysaccharide fraction from this plant. METHODS: Polysaccharides of S. dendroideum were extracted with water by infusion, fractionated by freeze-thawing process and dialyzed at a 100 kDa cut-off membrane, and characterized by monosaccharide composition and NMR analysis. The gastroprotective activity of the pectic polysaccharide fraction RSBAL was evaluated in the ethanol-induced ulcer model in rats, followed by determination of the mucus and glutathione levels in the gastric tissue. RESULTS: RSBAL was constituted by a homogalacturonan and a homogalacturonan branched by side chains of arabinans and type II arabinogalactans. It reduced ethanol-induced gastric ulcers in rats, preserving mucus and glutathione levels in the stomach. CONCLUSION: This study demonstrated that polysaccharides could be related to the pharmacological activity of S. dendroideum.

Acid-gastric antisecretory effect of the ethanolic extract from Arctium lappa L. root: role of H+, K+-ATPase, Ca2+ influx and the cholinergic pathway.

BACKGROUND: Arctium lappa L., popularly known as burdock, is a medicinal plant used worldwide. The antiulcer and gastric-acid antisecretory effects of ethanolic extract from roots of Arctium lappa (EET) were already demonstrated. However, the mechanism by which the extract reduces the gastric acid secretion remains unclear. Therefore, this study was designed to evaluate the antisecretory mode of action of EET. MATERIALS AND METHODS: The effects of EET on H+, K+-ATPase activity were verified in vitro, whereas the effects of the extract on cholinergic-, histaminergic- or gastrinergic-acid gastric stimulation were assessed in vivo on stimulated pylorus ligated rats. Moreover, ex vivo contractility studies on gastric muscle strips from rats were also employed. RESULTS: The incubation with EET (1000 µg/ml) partially inhibited H+, K+-ATPase activity, and the intraduodenal administration of EET (10 mg/kg) decreased the volume and acidity of gastric secretion stimulated by bethanechol, histamine, and pentagastrin. EET (100-1000 µg/ml) did not alter the gastric relaxation induced by histamine but decreased acetylcholine-induced contraction in gastric fundus strips. Interestingly, EET also reduced the increase in the gastric muscle tone induced by 40 mM KCl depolarizing solution, as well as the maximum contractile responses evoked by CaCl2 in Ca2+-free depolarizing solution, without impairing the effect of acetylcholine on fundus strips maintained in Ca2+ -free nutritive solution. CONCLUSION: Our results reinforce the gastric antisecretory properties of preparations obtained from Arctium lappa, and indicate that the mechanisms involved in EET antisecretory effects include a moderate reduction of the H+, K+-ATPase activity associated with inhibitory effects on calcium influx and of cholinergic pathways in the stomach muscle.

Chemical structure and anti-inflammatory effect of polysaccharides obtained from infusion of Sedum dendroideum leaves.

Sedum dendroideum is popularly known as balsam and used for treatment of inflammatory disorders. Two polysaccharides (RSBAL-H2O and RSBAL-0.5) were isolated from infusion of its dried leaves, using dialysis at 100kDa cut-off membrane and anion exchange chromatography. Methylation and NMR analyses showed that RSBAL-H2O is a highly methyl-esterified homogalacturonan, constituted by (1→4)-α-D-GalA residues, whereas RSBAL-0.5 is a highly methyl-esterified homogalacturonan branched at O-3, probably by type II arabinogalactans and arabinans. In this study we showed that these balsam polysaccharides stimulate secretion of the cytokines TNF-α, IL-1ß and IL-10 by THP-1 macrophages, acting as immunostimulatory agents. But, on the other hand, they reduce TNF-α and IL1-ß secretion induced by a pro-inflammatory agent (LPS), showing anti-inflammatory effect.

Sulfation of fucogalactan from Agaricus bisporus: Different patterns in the chemical structure and their effects on anticoagulant activity.

A fucogalactan from Agaricus bisporus was sulfated by two methodologies based on an optimized sulfation method. The direct action of chlorosulfonic acid and SO3-pyridine complex over the sulfation reaction and its effects on anticoagulant activity were evaluated. The products of chemical sulfations were two sulfated fucogalactans named E100 and ESL respectively. Clotting assays (APTT, PT and TT) showed that both sulfated polysaccharides have anticoagulant activity, and that ESL was more potent compared to E100. The FXa, T and FXIIa activities in the presence of the sulfated polysaccharides were determined. The better anticoagulant activity of ESL could be related to anti-FXIIa activity and also probably to its higher bioavailability. The HPSEC analysis showed similar Mw of 1.08×104gmol-1 and 1.00×104gmol-1 for E100 and ESL respectively. NMR and methylation analyses indicated a heterogeneous sulfation pattern for E100, whereas ESL showed conserved unsulfated (1→6)-linked α-d-Galp residues in the main-chain and a more homogeneous sulfation pattern. The DS values of ESL and E100 were 1.0 and 2.8 respectively, indicating that the sulfation pattern is more important for the anticoagulant activity than the amount of sulfate.

Identification of potential targets for an anticoagulant pectin.

Heparin is a sulfated polysaccharide of animal origin showing excellent anticoagulant properties. Although it strongly inhibits the coagulation cascade, its interaction with multiple sites results in several side effects. An ideal alternative compound should not only possess anticoagulant and antithrombotic activities, but also provide specific binding to components of the coagulation cascade to decrease side effects and facilitate the control of pharmacologic actions in patient's body. In this work, we performed a scan of potential targets for chemically sulfated pectin from Citrus sinensis (SCP) that shows an efficient anticoagulant activity by combining proteomics and molecular docking techniques. Defining the interaction partners of SCP is fundamental to evaluate if its pharmacological side effects can be as harmful as those from heparin. SCP interacts directly with heparin cofactor II, probably favoring its interaction with thrombin. SCP interaction with antithrombin depends likely on its association with thrombin or factor Xa. In addition to the interaction with factors related to homeostasis, SCP may also act on the renin-angiotensin and on the complement systems. BIOLOGICAL SIGNIFICANCE: The knowledge of potential molecular targets of SCP provides clues to understand its mechanism of action in order to guide molecular changes in this compound to increase its specificity.

Anticoagulant activity of native and partially degraded glycoglucuronomannan after chemical sulfation.

Heparin has great clinical importance as anticoagulant and antithrombotic agent. However, because of its risks of causing bleeding and contamination by animal pathogens, several studies aim to obtain alternatives to heparin. In the search for anticoagulant and antithrombotic agents from a non-animal source, a glycoglucuronomannan from the gum exudate of the plant Vochysia thyrsoidea was partially hydrolyzed, and both native and partially degraded polysaccharides were chemically sulfated, yielding VThS and Ph-VThS respectively. Methylation analysis indicated that sulfation occurred preferentially at the O-5 position of arabinose units in the VThS and at the O-6 position of mannose units in Ph-VThS. In vitro aPTT assay showed that VThS and Ph-VThS have anticoagulant activity, which could be controlled by protamine, and ex vivo aPTT assay demonstrated that Ph-VThS is absorbed by subcutaneous route. Like heparin, they were able to inhibit α-thrombin and factor Xa by a serpin-dependent mechanism. In vivo, VThS and Ph-VThS reduced thrombus formation by approximately 50% at a dose of 40 IU/kg, similarly to heparin. The results demonstrated that the chemically sulfated polysaccharides are promising anticoagulant and antithrombotic agents.

Monosaccharide composition of glycans based on Q-HSQC NMR.

Glycans have essential functions related to structural architecture and specific cell surface phenomena, such as differentiation, biosignalling, recognition and cell-cell interaction, with the carbohydrate structure determining main function in the cell. Due to the importance of the primary structure, the monosaccharide composition is crucial to show the glycan structure. We now present a method for complex carbohydrates based on NMR spectroscopy, which has shown to give similar results to those obtained by the classic GC-MS-carboxy-reduction/deuterium labeling approach. Quantitative HSQC, through JCH dependence showed 155 Hz as the best value for (1)H/(13)C anomeric aldoses, allowing milli-microM detection using conventional inverse probe heads. Combining the quantification of native monosaccharide units of the glycan and those from the hydrolyzed product, a strong correlation occurs between the molecular mobility of the monosaccharide units, giving rise to some insights on the dynamic properties of the parent glycan.

Rhamnogalacturonan from Acmella oleracea (L.) R.K. Jansen: gastroprotective and ulcer healing properties in rats.

A rhamnogalacturonan (RGal) isolated from Acmella oleracea (L.) R.K. Jansen administered by oral route showed gastroprotective activity against acute lesions induced by ethanol. In this study, we investigated the gastric ulcer healing effect of RGal and its mechanisms of action. Intraperitoneal treatment of animals with RGal protected the gastric mucosa against acute lesions induced by ethanol, with participation of gastric mucus. Furthermore, in the chronic ulcer model, oral administration of RGal accelerates the gastric ulcer healing, accompanied by increasing of cellular proliferation and gastric mucus content, reducing inflammatory parameters and oxidative stress. In addition, the repeated 7 days-treatment of animals with RGal did not show alterations of clinical and behavioral symptoms, body and organs weights or plasmatic biochemical parameters. Collectively, these results showed that RGal has an interesting antiulcerogenic activity and could constitute an attractive molecule of interest for the development of new antiulcer agents.