Evaluation of natural gum-based cryogels for soft tissue engineering.

In this study, three natural biomaterials, Locust bean gum (LBG), Xanthan gum (XG), and Mastic gum (MG), were combined to form cryogel scaffolds. Thermal and chemical characterizations revealed the successful blend formation from LBG-XG (LX) and LBG-XG-MG (LXM) polymers. All blends resulted in macro-porous scaffolds with interconnected pore structures under the size of 400 µm. The swollen cryogels had similar mechanical properties compared with other polysaccharide-based cryogels. The mean tensile and compressive modulus values of the wet cryogels were in the range of 3.5-11.6 kPa and 82-398 kPa, respectively. The sustained release of the small molecule Kartogenin from varying concentrations and ratios of cryogels was in between 32 and 66% through 21 days of incubation. Physical, mechanical, and chemical properties make LX and LXM polysaccharide-based cryogels promising candidates for cartilage and other soft tissue engineering, and drug delivery applications.

Structural characterization of novel arabinoxylan and galactoarabinan from citron with potential antitumor and immunostimulatory activities.

This study aimed to extract polysaccharides from citron and analyze their structures and potential bioactivities. Two novel polysaccharides CM-1 and CM-2 were purified from citron by DEAE-Sepharose Fast Flow and Sephadex G-100 column chromatography. Monosaccharide composition, linkage and NMR data were used to infer their sugar chains composition. The anti-breast cancer cells and immunoregulatory activities of CM-1 and CM-2 were investigated. Results indicated that CM-1 (Mw = 21,520 Da), composed of arabinose, xylose, mannose and glucose in a molar ratio of 10.78:11.53:1.00:1.70, was arabinoxylan (AX) with (1 â†’ 4)-linked ß-d-Xylp skeleton monosubstituted with α-l-Araf units at O-3 position. While CM-2 (Mw = 22,303 Da), composed of arabinose, mannose, glucose and galactose in a molar ratio of 25.46:1.45:1.00:6.57, was galactoarabinan (GA) with (1 â†’ 5)-linked α-l-Araf backbone substituted by ß-d-Galp units at O-2 and/or O-3 positions. Both polysaccharides exhibited potential inhibiting cancer and immunostimulatory activities in vitro, especially CM-1. These results provide a basis for further research on citron polysaccharides.

The structure elucidation of novel arabinogalactan LRP1-S2 against pancreatic cancer cells growth in vitro and in vivo.

The fruit of Lycium ruthenicum Murr is used as traditional medicine and functional food. Previously we reported that one RG-I pectin from this fruit might inhibit pancreatic cancer cells growth. We further hypothesized that there might be other type of polysaccharides in this fruit also have anti-tumor effect. Here, we showed novel structure of a homogeneous polysaccharide named LRP1-S2 from this fruit and its anti-pancreatic cancer effect. Structure analyses suggested that LRP1-S2 was a novel arabinogalactan with the molecular weight (Mw) of 17.0 kDa. Bioactivity test showed that LRP1-S2 might attenuate the proliferation of pancreatic cancer cells in vitro and in vivo without significant cytotoxicity to normal pancreatic HPDE6-C7 cells and LO2 liver cells. Mechanism study indicated that it might induce apoptosis of BxPC-3 by inactivating P38 MAPK/NF-κB and GSK-3ß/ß-Catenin signaling pathways. These results suggested that LRP1-S2 could be a potential anti-tumor leading compound for functional food and new drug development. CHEMICAL COMPOUNDS: arabinogalactan, pectin, galactan, arabinan, RN-1, HH1-1, LRP1-S2, LRP3-S1.

Engineering butylglyceryl-modified polysaccharides towards nanomedicines for brain drug delivery.

Colloidal systems prepared from carbohydrates are subject of intense research due to their potential to enhance drug permeability through biological membranes, however their characteristics and performance are never compared directly. Here we report the results of a comparative investigation of a series of butylglyceryl-modified polysaccharides (chitosan, guar gum, and pullulan) that were formulated into nanoparticles and loaded with a range of model actives (Doxorubicin, Rhodamine B, Angiotensin II). Butylglyceryl-modified guar gum and corresponding pullulan nanocarriers were more stable at physiological pH compared to those obtained from modified chitosan, and studies of the in-vitro interactions with mouse brain endothelial cells (bEnd3) indicated an increased biological membrane permeability and lack of toxicity at application-relevant concentrations. No significant haemolytic effect was observed, and confocal microscopy and flow cytometry studies confirmed the efficient cellular uptake and cytoplasmic localisation of NPs. Most promising characteristics for brain drug delivery applications were demonstrated by butylglyceryl pullulan nanocarriers.

Mucoadhesive guargum hydrogel inter-connected chitosan-g-polycaprolactone micelles for rifampicin delivery.

Natural polymer guar gum has one of the highest viscosities in water solution and hence, these are significantly used in pharmaceutical applications. Guar gum inter-connected micelles as a new carrier has been developed for poor water soluble rifampicin drug. The hydrogel inter-connected micelle core was formulated as a hydrophilic inner and hydrophobic outer core by using guar gum/chitosan/polycaprolactone and the carrier interaction with rifampicin was confirmed by FT-IR. The morphological observations were carried out through TEM, SEM and AFM analysis. The encapsulation efficiency and in-vitro drug release behavior of prepared hydrogel based micelle system was analyzed by UV-vis spectrometry. The anti-bacterial activity against K. pneumoniae and S. aureus was studied by observing their ruptured surface by SEM. The cytotoxicity study reveals that the pure polymeric system has no toxic effect whereas drug loaded ones showed superior activity against THP-1 cells. From the cell apoptosis analyses, the apoptosis was carried out in a time dependent manner. The cell uptake behavior was also observed in THP-1 cells which indicate that the hydrogel based micelle system is an excellent material for the mucoadhesive on intracellular alveolar macrophage treatment.

Smart wound dressing based on κ-carrageenan/locust bean gum/cranberry extract for monitoring bacterial infections.

A smart wound dressing based on carrageenan (κC), locust bean gum (LBG), and cranberry extract (CB) for monitoring bacterial wound infections was developed and characterized using UV-vis spectroscopy, FT-IR, and SEM. The mechanical, swelling, cytotoxic and pH sensor properties were also investigated. UV-vis spectra demonstrated that the obtained κC:LBG:CB hydrogel film exhibited a visible change of colors as it was immersed in PBS solution pH 5.0, 7.3 and 9.0. The spectra of FT-IR suggested that chemical interactions had occurred between κC and CB extract. The obtained κC:LBG:CB hydrogel film exhibited adequate mechanical properties and a swelling behavior dependent on pH. Cytotoxicity tests indicated that κC:LBG:CB hydrogel film had dose-dependent cytotoxicity against NIH 3T3 fibroblast cells. The in vitro studies using Staphylococcus aureus and Pseudomonas aeruginosa demonstrated that the color changes of the κC:LBG:CB hydrogel film could be observed by naked eyes, confirming the potential use of the obtained hydrogel film as a visual system for monitoring bacterial wound infections.

Modifiable natural gum based microgel capsules as sustainable drug delivery systems.

Few hundred micrometer size microgel capsules from natural locust bean gum (LBG) was synthesized by means of divinyl sulfone (DVS) crosslinking in a surfactant free cyclohexane medium with 100% yield in 1 h. These LBG microgel capsules were chemically modified with different numbers of linear amine containing modifying agents such as ethylenediamine (EDA), diethylenetriamine (DETA), triethylenetetraamine (TETA) and branched polyethyleneimine (PEI) to induce cationic character for LBG microgels. The biggest change in zeta potential of LBG microgels that is +44.9 mV from -17.67 mV was observed upon the modification of LBG microgels with branched PEI (LBG/PEI). The blood compatibility studies were revealed that bare LBG microgels possess a good blood compatibility with non-hemolytic value, 0.96 ± 0.15%, and high blood clotting index, 87.35 ± 4.10%, whereas the blood compatibility of LBG/PEI microgels was found to be slightly-hemolytic, 4.96 ± 1.03%, and also moderate blood clotting index, 65.98 ± 98%. Additionally, sodium diclofenac (SDC) as a model drug was loaded into the LBG based microgels by directly loading from solution (absorption) and by chemical conjugation methods for in vitro release studies at physiological conditions, pH 7.4 at 37.5 °C A longer, and sustainable drug release profiles were obtained from chemical drug conjugated LBG microgels and the amine modified LBG microgels.

Cytotoxic effect of a mannogalactoglucan extracted from Agaricus bisporus on HepG2 cells.

A mannogalactoglucan (RK2-Ab; Mw 1.8×104gmol-1) composed by Man (27.3%), Gal (24.4%) and Glc (48.3%) was extracted and characterized from Agaricus bisporus, and its biological activity was evaluated on human hepatocarcinoma cells (HepG2). The partially-O-methylated alditol acetates together with the NMR data suggest the main chain to be composed of α-d-Galp (32.8%) and ß-d-Glcp (37.0%) units (1→6)-linked, with ß-d-Manp (14.6%), as non-reducing end units, substituting the side chains at O-2 (α-d-Galp units; 3.3%) and O-2 and O-4 (ß-d-Glcp units; 3.6%). (1→2)-linked ß-d-Glcp (2.7%) and ß-d-Manp (6.0%) can also be observed. RK2-Ab reduced cellular viability of HepG2 cells, by both, the MTT and lactate dehydrogenase release assays, promoted the increase of cytochrome c release and decrease of ATP content. Suggesting that the mannogalactoglucan from A. bisporus may have antitumor activity by inducing apoptosis by the mitochondrial death pathway, and could be used in cancer therapy.

Expression of caspase-3 and bcl-2 proteins as an indicator of functional state of brain tissue in white rats exposed to argentumarabinogalactane.

The article presents results on experimental modelling an influence of silver nanoparticles incorporated into natural polymer arabinogalactane matrix on brain tissue of white outbred rats. The rats underwent parenteral injection of silver nanoparticles incorporated into polymer arabinogalactane matrix (dosage of 100 and 500 micrograms of silver per kg of the animal weight). The studies covered expression of 2 proteins participating in apoptosis process, in mitochondrial activation type - caspase-3 and protein bcl-2. During experiment, the groups examined demonstrated significant dose-dependent effect of bcl- 2 protein expression and increased number of caspase-3 expressed and non-expressed hyperchromic cells under exposure to argentumarabinogalactane - that indicates disorders of cellular structure and apoptosis development.

Safety Assessment of Galactomannans as Used in Cosmetics.

The Cosmetic Ingredient Review Expert Panel (Panel) reviewed the safety of 16 galactomannans as used in cosmetics. These ingredients are legume polysaccharides that function mostly as hair/skin-conditioning agents and viscosity-increasing agents in cosmetic products. Their substantial molecular sizes suggest that skin penetration of these ingredients would be unlikely. The Panel concluded that these galactomannans are safe in the present practices of use and concentration described in this safety assessment.

Activity, reduced toxicity, and scale-up synthesis of amphotericin B-conjugated polysaccharide.

Amphotericin B (AMB) arabinogalactan (AG) conjugate was synthesized by the conjugation of AMB to oxidized AG by reductive amination. The conjugate was evaluated for in vitro antifungal activity and in vivo toxicity. Optimization of the conjugation process was investigated using large batches of 100 g, which are 20 times larger than previously reported for AMB-AG conjugation. The efficacy of AMB-AG conjugates was studied as a function of reaction conditions and time, aldehyde/reducing agent mole ratio, and purification procedure. The most potent AMB-AG conjugate having low minimal inhibitory concentration (MIC) and high maximal tolerated dose (MTD) was obtained following reduction with NaBH4 at 1:2 mol ratio (AG units/NaBH4) at 25 °C for 24 h. AMB-AG conjugate prepared under these conditions demonstrated MIC of 0.5 mg/L (equiv of AMB) in Candida albicans, and an MTD of 60 mg/kg (equiv of AMB) in mice, while AMB clinical formulation (Fungizone) demonstrated high toxicity (MTD = 3 mg/kg). These findings confirm the simplicity and reproducibility of the conjugation allowing this method to be applied on larger scale production.

Structure and anti-metapneumovirus activity of sulfated galactans from the red seaweed Cryptonemia seminervis.

The anti-HMPV (human metapneumovirus) activity was determined for sulfated dl-hybrid galactans obtained from the red seaweed Cryptonemia seminervis and their depolymerized products obtained by reductive partial hydrolysis. Structural studies carried out in three homogeneous depolymerized fractions DS-1, DS-2e and DS-3 (Mw of 51.6-63.8 kDa) showed that these galactans present different chemical characteristics, as monosaccharide composition, content of sulfate groups (14.1-29.9%) and agaran:carrageenan molar ratio diads, 2.7:1 for DS-1 and DS-2e and 1:1 for DS-3. The sulfate groups are located principally on C-2 of ß-d-galactopyranose and 4,6-O-(1'-carboxyethylidene)-ß-d-galactopyranose residues and on C-6 of α-galactose residues. Sulfated dl-galactans and their depolymerized products exhibited antiviral activity at a very early stage of the viral infection cycle. All fractions, except DS-2e inhibited HMPV replication by binding to the viral particle. Besides depolymerized galactans DS-2e and DS-3 inhibited the recognition of cell receptor by HMPV and penetration to the host cell, respectively.

A comprehensive evaluation of the toxicology of the "Deli" cast sheet process used in experimental cigarettes.

CONTEXT: Manufacture of cigarettes results in tobacco by-products, some of which can be processed and added back to cigarettes. Such additions (known as reconstituted tobacco or reconstituted leaf) have been shown to reduce tar yields. A new process (termed "Deli" cast sheet) is a potential refinement of the reconstitution process. OBJECTIVE: Compare toxicity of smoke from experimental cigarettes made with reconstituted leaf with that from cigarettes made with Deli cast sheet. MATERIALS AND METHODS: Analytical chemistry, Salmonella mutagenicity and cytotoxicity assays were used to evaluate the composition biological activity of mainstream smoke from experimental cigarettes made with Deli cast sheet or with reconstituted leaf. The effect of different amounts of guar and propylene glycol in Deli cast sheet was also evaluated. RESULTS: Small increases in the amount of nitrogen oxides were found as a result of inclusion of the Deli cast sheet when compared with reconstituted leaf; no differences in cytotoxicity or mutagenicity were found. CONCLUSION: The Deli process neither significantly modified chemical composition of smoke nor affected its biological activity, as measured by the mutagenicity and cytotoxicity assays used here.

Occupational rhinitis caused by concurrent sensitization to two different allergens.

BACKGROUND: Exposure to wheat flour and guar gum is a well-known cause of occupational respiratory allergies among workers in the food processing industry. To date, there have been no reports of occupational rhinitis (OR) caused concurrently by two different allergens present in the workplace. AIMS: To report a case of OR likely to be induced concurrently by exposure to wheat flour and guar gum in a mid-40s male employed in the food processing industry. METHODS: Allergy tests and nasal challenge tests were performed to investigate and confirm the diagnosis of OR. We discuss potential mechanisms involved in the observed dual sensitization. RESULTS: The patient showed positive responses to wheat and guar gum extracts on skin prick testing. The total IgE was 1680 kU/l (0-100 kU/l). The diagnosis of OR was confirmed by nasal challenge tests with wheat flour and guar gum on different days. In contrast to the control day, the challenge with flour and guar gum induced an immediate clinical reaction associated with a decrease in nasal volume measured by acoustic rhinometry. The patient was advised to avoid exposure to wheat and guar gum, which resulted in a gradual resolution of nasal symptoms. CONCLUSIONS: Co-sensitization and cross-reactivity are possible mechanisms involved in cases of concurrent sensitization to related and unrelated allergens in patients complaining of work-related rhinitis symptoms.

Arabinogalactan as active compound in the management of corneal wounds: in vitro toxicity and in vivo investigations on rabbits.

PURPOSE: Aims of the present investigation were to prove that natural polysaccharide arabinogalactan (AG) is well tolerated after ocular administration and exerts a high restoring effect on corneal epithelium abrasions. MATERIALS AND METHODS: AG interactions with corneal cells, as well as its effect on their proliferation, were evaluated employing rabbit corneal epithelial cell cultures. The effects due to the presence of benzalkonium chloride (BAK) were also studied on cell cultures, ex vivo on rabbit isolated corneas, evaluating the hydration level, and on the healing rate of experimental corneal wounds in rabbits. Furthermore, the healing process of corneal lesions treated with an experimental 5.0% AG solution was studied and compared with those obtained applying solutions of hyaluronic acid and tamarind seed polysaccharide, both chosen as a reference by virtue of their well-known adjuvant properties on corneal trophism; the study was carried out by light and transmission electron microscopy. RESULTS: BAK showed toxic effects on corneal epithelium in all experiments. AG proved to stimulate the growth of the corneal epithelial cells by interacting at the level of the cell plasma membrane. The microscopy observations of the epithelial surface of AG-treated damaged corneas revealed a well-restored and histologically organized ultrastructure characterized by fully formed microvilli and glycocalyx; the healing process resulted faster with respect to spontaneously recovered untreated corneas. CONCLUSION: Our results suggest that AG can interact with corneal epithelial cells without any toxic side effect; moreover, it proved to stimulate cell proliferation, thus promoting tissue re-epithelialization and reorganization just 48 hr post-wounding.

Antithrombin and heparin cofactor II-mediated inactivation of alpha-thrombin by a synthetic, sulfated mannogalactan.

INTRODUCTION: A mannogalactan from Pleurotus ostreatoroseus (MgPr) was chemically sulfated to give MgPr-S1, which was evaluated for its anticoagulant and antithrombotic activities, bleeding tendency, and platelet aggregation. MATERIALS AND METHODS: MgPr-S1 was partially characterized by HPSEC-MALLS, methylation analysis, and 13C NMR spectroscopy. Its anticoagulant activity was determined by assays of aPTT, TT, alpha-thrombin and factor Xa residual activity, heparin cofactor II (HCII)-, or antithrombin (AT)-mediated inhibition. The antithrombotic effect was evaluated in rats using a venous thrombosis model and the bleeding tendency was also tested in vivo. Platelet aggregation was investigated by an adaptation of the method of Born [1]. RESULTS: The hydroxyl groups of beta-D-Manp units and OH-2 and OH-4 of the (1-->6)-linked alpha-D-Galp units were preferentially substituted. The anticoagulant activity of MgPr-S1 was mainly by thrombin inhibition with antithrombin and HCII, and had an effect on platelet aggregation induced by ADP and alpha-thrombin. It almost completely inhibited thrombus formation in vivo at a dose of 6 mg/kg and heparin inhibited thrombus formation at a dose of 0.200 mg/kg. CONCLUSIONS: These results suggested that the chemically sulfated mannogalactan could act as an alternative to heparin as anticoagulant.

Reproductive and developmental toxicity evaluation of a purified Arabinogalactan-Protein (AGP) composition in Wistar rats.

A purified Arabinogalactan-Protein composition (LL-4218) was prepared from the leaves of Argemone mexicana to treat psoriasis. The effect of (LL-4218) was evaluated on reproductive (male and female fertility) and developmental toxicity in rats. LL-4218 was administered orally at the doses of 250, 500 and 1000 mg kg(-1). The results showed that LL-4218 did not produce any significant dose related changes in reproductive and developmental toxicity studies. Therefore, it is concluded that LL-4218 did not produce any significant toxic effect on reproduction and developmental parameters of rats and NOAEL for reproductive and developmental toxicity studies in rats was 1000 mg kg(-1).

Conjugation of amino-containing drugs to polysaccharides by tosylation: amphotericin B-arabinogalactan conjugates.

The coupling of amphotericin-B (AmB), a water-insoluble antifungal and antileishmanial agent, to arabinogalactan (AG) via tosylate or mesylate derivatives was investigated as a method for the conjugation of amino-containing drugs to polysaccharides. In the first step, AG was reacted with tosyl- or mesyl-chloride at different ratios to obtain tosylate or mesylate AG derivatives. AmB was conjugated to AG derivatives in either aqueous or organic media via an amine bond. AG-AmB conjugates were soluble in water and exhibited improved stability in aqueous solutions as compared to the unbound drug. The conjugates showed comparable inhibitory concentration values against the pathogenic yeast Candida albicans, and against Leishmania major parasites. They were about 60 times less hemolytic against sheep erythrocytes than the free drug, and less toxic when injected i.v. to BALB/c mice.

Novel DL-galactan hybrids from the red seaweed Gymnogongrus torulosus are potent inhibitors of herpes simplex virus and dengue virus.

A novel series of DL-galactan hybrids extracted from the red seaweed Gymnogongrus torulosus, was evaluated for its in vitro antiviral properties against herpes simplex virus type 2 (HSV-2) and dengue virus 2 (DEN-2). These compounds were very active against both viruses with inhibitory concentration 50% (IC50) values in the range 0.6-16 microg/ml for HSV-2 and 0.19-1.7 microg/ml for DEN-2, respectively, as determined in a virus plaque reduction assay in Vero cells. The DL-galactans lacked of cytotoxic effects, on stationary as well as on actively dividing cells, and anticoagulant properties. Some of the compounds showed a variable level of direct inactivating effect on both virions, with virucidal concentration 50% values exceeding the IC50s obtained by plaque reduction assay. Full inhibitory activity was achieved when the galactans were present during virus adsorption period, suggesting that the mode of action of these compounds is an interference in the binding of the surface envelope glycoprotein with the cell receptor.

A novel injectable water-soluble amphotericin B-arabinogalactan conjugate.

New, stable, highly water-soluble, nontoxic polysaccharide conjugates of amphotericin B (AmB) are described. AmB was conjugated by a Schiff-base reaction with oxidized arabinogalactan (AG). AG is a highly branched natural polysaccharide with unusual water solubility (70% in water). A high yield of active AmB was obtained with the conjugates which were similarly highly water soluble and which could be appropriately formulated for injection. They showed comparable MICs for Candida albicans and Cryptococcus neoformans (MICs, 0.1 to 0.2 microg/ml). The reduced AmB conjugate, which was synthesized at pH 11 for 48 h at 37 degrees C, was nonhemolytic and was much safer than conventional micellar AmB-deoxycholate. It was the least toxic AmB-AG conjugate among those tested with mice (maximal tolerated dose, 50 mg/kg of body weight), and histopathology indicated no damage to the liver or kidneys. This conjugate, similarly to the liposomal formulation (AmBisome), was more effective than AmB-deoxycholate in prolonging survival. It was more effective than both the liposomal and the deoxycholate formulations in eradicating yeast cells from target organs. The overall results suggest that after further development of the AmB-AG conjugate, it may be a potent agent in the treatment of fungal infections.