Gum arabic (GA) modifies paracellular water and electrolyte transport in the small intestine

Active Fractions of Methanol Crude Obtained from Acacia seyal gum: Antioxidant Capacity, using FTIR Analysis

The present study is on Acacia seyal gum (ASG), which is an exudate from Talha tree. It provides a rich source of polyphenolics compounds that are used traditionally in folk medicine. The study aims to determine the antioxidant capacity (AC) and functional groups of ASG and Prebio-T-commercial (PTC) samples. The methanol crude extracts of both ASG and PTC have fractioned into chloroform (CHF), hexane (HF), acetone (AF) and methanol (MF) using solvent-solvent portion. Both ferric reducing antioxidant power (FRAP), and cupric reducing antioxidant capacity (CUPRAC) assays for each fraction examined. Crude methanol extracts (CME) and its active compositions also analysed carefully using Fourier Transform Infrared Spectroscopy (FTIR) technique. The findings presented a wide variety of functional groups provided by the FTIR spectra (eights bands approximately. Regarding cupric reducing antioxidant capacity (CUPRAC), the methanol crude extracts values are 888.6�4.57 mg TE/100g extract, for PTC as compared to 474.3� 2.23 mg TE/100g of extract for ASG. However, both methanol and acetone fractions revealed significantly (p = 0.05) high FRAP values ranged between 599.8�7.5 and 741.8�5.8 mg TE/100g fraction; for PTC and ASG, respectively. While CUPRAC showed insignificant (p = 0.05) same values 356.1�2.62 mg TE/100g of fraction; for MF of both PTC and ASG respectively. Therefore, in this study, methanolic fractions (MFs) are found to be more effective than acetone fractions (AFs), except for CHF and HF. Finally, the antioxidant activity of the active fraction has provided some evidence regarding its functional groups which may have used in traditional medicine.

Antioxidant Potential and Angiotensin-Converting Enzyme (ACE) Inhibitory Activity of Orotic Acid-Loaded Gum Arabic Nanoparticles

Orotic acid (OA) nanoparticles were prepared using the freeze-drying method. The antihypertensive activity and antioxidant capacity of OA and orotic acid-loaded gum arabic nanoparticles (OAGANPs) were examined using the angiotensin-converting enzyme (ACE), 1,1-diphenyl-2-picrylhydrazyl (DPPH), nitric oxide (NO), and β-carotene assays, as well as the quantification of total phenolic content (TPC). The DPPH and NO scavenging activities of OAGANPs were significantly higher than those of the OA solution. The β-carotene bleaching assay of OAGANPs showed a dose-dependent trend, while 500 μg/ml was significantly more effective than the other concentrations, which exerted 63.4% of the antioxidant activity. The in vitro antihypertensive assay revealed that the OAGANPs exhibited the most potent ACE inhibition activity, when compared to the OA solution. Hence, results revealed the potential of preparing the OA as a nanoparticle formulation in enhancing the antioxidant and antihypertensive properties compared to the OA solution.

Salt reduction in liquid/semi-solid foods based on the mucopenetration ability of gum arabic

Gum arabic enhances the saltiness perception of liquid/semi-solid foods via a mucopenetration effect.

Water transport and functional dynamics of aquaporins in osmoregulatory organs of fishes

Aquaporins play distinct roles for water transport in fishes as they do in mammals-both at the cellular, organ, and organismal levels. However, with over 32,000 known species of fishes inhabiting almost every aquatic environment, from tidal pools, small mountain streams, to the oceans and extreme salty desert lakes, the challenge to obtain consensus as well as specific knowledge about aquaporin physiology in these vertebrate clades is overwhelming. Because the integumental surfaces of these animals are in intimate contact with the surrounding milieu, passive water loss and uptake represent two of the major osmoregulatory challenges that need compensation. However, neither obligatory nor regulatory water transport nor their mechanisms have been elucidated to the same degree as, for example, ion transport in fishes. Currently fewer than 60 papers address fish aquaporins. Most of these papers identify "what is present" and describe tissue expression patterns in various teleosts. The agnathans, chondrichthyans, and functionality of fish aquaporins generally have received little attention. This review emphasizes the functional physiology of aquaporins in fishes, focusing on transepithelial water transport in osmoregulatory organs in euryhaline species - primarily teleosts, but covering other taxonomic groups as well. Most current knowledge comes from teleosts, and there is a strong need for related information on older fish clades. Our survey aims to stimulate new, original research in this area and to bring together new collaborations across disciplines.

Independence of net water flux from paracellular permeability in the intestine of Fundulus heteroclitus, a euryhaline teleost

Paracellular permeability and absorptive water flux across the intestine of the euryhaline killifish were investigated using in vitro gut sac preparations from seawater- and freshwater-acclimated animals. The permeability of polyethylene glycol (PEG), a well-established paracellular probe, was measured using trace amounts of radiolabelled oligomers of three different molecular sizes (PEG-400, PEG-900 and PEG-4000) at various times after satiation feeding. All three PEG molecules were absorbed, with permeability declining as a linear function of increasing hydrodynamic radius. Response patterns were similar in seawater and freshwater preparations, though water absorption and PEG-900 permeability were greater in the latter. Despite up to 4-fold variations in absorptive water flux associated with feeding and fasting (highest at 1-3 h, lowest at 12-24 h and intermediate at 1-2 weeks post-feeding), there were no changes in PEG permeability for any size oligomer. When PEG permeability was measured in the opposite direction (i.e. serosal to mucosal) from net water flux, it was again unchanged. HgCl(2) (10(-3) mol l(-1)), a putative blocker of aquaporins, eliminated absorptive water flux yet increased PEG-4000 permeability by 6- to 8-fold in both freshwater and seawater preparations. Experimentally raising the serosal osmolality by addition of 300 mmol l(-1) mannitol increased the absorptive water flux rate 10-fold, but did not alter PEG permeability. Under these conditions, HgCl(2) reduced absorptive water flux by 60% and again increased PEG permeability by 6- to 8-fold in both freshwater and seawater preparations. Clearly, there was no influence of solvent drag on PEG movement. The putative paracellular blocker 2,4,6-triaminopyrimidine (TAP, 20 mmol l(-1)) had no effect on net water flux or PEG permeability. We conclude that PEG and water move by separate pathways; absorptive water transport probably occurs via a transcellular route in the intestine of Fundulus heteroclitus.

Synthesis and evaluation of ampicillin-conjugated gum arabic microspheres for sustained release

Ampicillin was conjugated to periodate-oxidized gum arabic (GA), a branched polysaccharide, to form the imino conjugate of the drug and the polysaccharide. The water-soluble conjugate was dispersed by sonication in a mixture of toluene and liquid paraffin in the presence of a non-ionic surfactant as droplet stabilizer and fabricated into microspheres by heat denaturation at 80°C to obtain spheres less than 2 μm in diameter. These microspheres did not undergo dissolution in water on prolonged incubation. In-vitro release of ampicillin into phosphate buffer from the microspheres was slow and sustained with a cumulative release between 10 and 25% of the drug content in 10 days depending on the degree of oxidation of GA and the drug payload. Release into simulated gastric fluid was faster due to faster hydrolysis of the drug-GA bond in the acid medium, but when the medium was changed to intestinal fluid, the release was slowed down. Ampicillin released was functionally active and inhibited the growth of S. aureus and E. coli in cultures, although not as actively as free ampicillin. The microspheres underwent slow biodegradation on prolonged incubation in aqueous media. These studies show that ampicillin conjugated with oxidized GA and fabricated into microspheres possesses sustained-release characteristics for prolonged periods.

Biological effects of gum arabic: a review of some recent research

Gum arabic (GA) is a branched-chain, complex polysaccharide, either neutral or slightly acidic, found as a mixed calcium, magnesium and potassium salt of a polysaccharidic acid. The backbone is composed of 1,3-linked beta-D-galactopyranosyl units. The side chains are composed of two to five 1,3-linked beta-D-galactopyranosyl units, joined to the main chain by 1,6-linkages. Pharmacologically, GA has been claimed to act as an anti-oxidant, and to protect against experimental hepatic-, renal- and cardiac toxicities in rats. These reports could not be confirmed by others. GA has been claimed to alleviate the adverse effects of chronic renal failure in humans. This could not be corroborated experimentally in rats. Reports on the effects of GA on lipid metabolism in humans and rats are at variance, but mostly suggest that GA ingestion can reduce plasma cholesterol concentrations in rats. GA has proabsorptive properties and can be used in diarrhoea. It enhances dental remineralization, and has some antimicrobial activity, suggesting a possible use in dentistry. GA has been shown to have an adverse effect on electrolyte balance and vitamin D in mice, and to cause hypersensitivity in humans. More studies are needed before the pharmacological properties of GA can be utilized in therapy.

Systematic review and meta-analysis: the clinical and physiological effects of fibre-containing enteral formulae

BACKGROUND

Enteral nutrition can be associated with gastrointestinal side effects and fibre supplementation has been proposed as a means to normalize bowel function.

AIM

To evaluate systematically the effects of fibre supplementation of enteral feeds in healthy volunteers and patients both in the hospital and community settings.

METHODS

Electronic and manual bibliographic searches were conducted. Controlled studies in adults or children, comparing fibre-supplemented vs. fibre-free formulae given as the sole source of nutrition for at least 3 days, were included.

RESULTS

Fifty-one studies (including 43 randomized-controlled trials), enrolling 1762 subjects (1591 patients and 171 healthy volunteers) met the inclusion criteria. Fibre supplementation was generally well tolerated. In the hospital setting, the incidence of diarrhoea was reduced as a result of fibre administration (OR 0.68, 95% CI: 0.48-0.96; 13 randomized-controlled trials). Meta-regression showed a more pronounced effect when the baseline incidence of diarrhoea was high. In both patients and healthy subjects, fibre significantly reduced bowel frequency when baseline frequency was high and increased it when it was low, revealing a significant moderating effect of fibre.

CONCLUSIONS

The review indicates that the fibre-supplemented enteral formulae have important physiological effects and clinical benefits. There is a need to use a consistent approach to undertake more studies on this issue in the community setting.

Modulation of rat intestinal nuclear factor NF-kappaB by gum arabic

The objective of this study was to test the hypothesis that in an animal model of cathartic-induce intestinal dysfunction the proabsorptive effects of gum arabic (GA) could be associated with modulation of nuclear factor-kappaB (NF-kappaB) and with reduction of the inflammatory response caused by cathartics, as evidenced by intestinal mucosa cytokine production and gene expression. Juvenile male rats were given a phenolphthalein-magnesium citrate solution for 6 days, by itself or supplemented with either 10 or 20 g L(-1) GA, as a sole source of fluid. The controls given were tap water alone or with added 20 g L(-1) GA. The animals were euthanized and small-intestinal mucosa nuclear fractions and RNA were isolated. NF-kappaB p65 activity was highest after administration of cathartics, lowest in controls, and intermediate in GA-treated rats. Mucosal IL-1beta was overexpressed in tissues from cathartic-treated rats and from rats given high-GA solutions. Gene-array analysis revealed a complex pattern of gene regulation by cathartics which selectively upregulated several subfamilies of cytochrome P-450 family 2 genes. Co-administration of GA did not block this effect. These findings suggest that local anti-inflammatory effects on the small intestine could be obtained by administration of a nonabsorbable proteoglycan such as GA.

Enhancement of absorption by gum arabic in a model of gastrointestinal dysfunction

OBJECTIVE

Diarrhea is a common and deadly threat to millions of infants and children. Similarly, malabsorption can aggravate the health status of the chronically sick and especially the elderly. Prompt recovery from intestinal dysfunction may have a substantial impact on many populations. The aim of this study was to test the hypothesis that, in an animal model of cathartic-induce diarrhea, the previously shown proabsorptive effects of gum arabic (GA) could directly reduce and ameliorate intestinal dysfunction.

METHODS

Young male rats were offered a standard solid feed and as a sole source of fluid a phenolphthalein-magnesium citrate solution for 3 or 6 days (PC), or the same plus either 10 (GA1) or 20 (GA2) g/L of GA. Other groups had tap water without (CTL) or with 20 g/L GA (CTL + GA), after which the animals were jejunally perfused under anesthesia to test their absorptive capacity. Similarly treated rats were killed and the small intestinal mucosa scraped and processed for nitric oxide synthase (NOS) determination.

RESULTS

In 6-day studies addition of GA to the cathartic solution led to increases in net water, sodium and glucose absorption with the higher GA2, relatively to the PC rats. For water (means +/- SEM): PC = 42.4 +/- 3.6; GA2 = 57.9 +/- 3.9 nmol/g.min, p < 0.05. For sodium: PC = 2,139 +/- 334; GA2 = 4,465 +/- 444 nmol/g.min, p < 0.05. After only 3-day exposure, effects were less marked. Total NOS activity was increased in the PC, GA1 and GA2 groups (333 +/- 26; 334 +/- 27; 336 +/- 23 nmol/h.g) compared to CTL (233 +/- 27 nmol/h.g, p < 0.05), while CTL + GA showed a further reduction of activity (190 +/- 18 nmol/h.g, p < 0.05 vs. CTL).

CONCLUSIONS

These findings substantiate earlier physiologic and biochemical effects of GA on the gastrointestinal tract, presently conducted in a model of gastrointestinal dysfunction. The data further suggest that a natural proteoglycan such as GA can reduce secretory effects induced by cathartics and, hence, are predictive of potential effectiveness in the context of diarrhea or malabsorption by infectious or functional causes.

[Progress in therapy for testicular tumors]

Approximately 80% of patients with metastatic testicular tumors are cured by cisplatin-containing chemotherapy and surgery. However, the remaining 20% of patients with advanced testicular tumors can not be cured at present. Thus, therapy for these testicular tumors infractory to treatment is the most important issue. Recently, chemotherapy for such tumors is developing, especially salvage chemotherapy using novel anticancer agents(paclitaxel, gemcitabine,irinotecan, docetaxel, oxaliplatin, etc) and high-dose anticancer drugs. Some of the new modalities are very attractive. In this article, we reviewed mainly these new forms of chemotherapy for testicular tumors.

Proabsorptive effect of gum arabic in isotonic solutions orally administered to rats: effect on zinc and other solutes

We have previously shown that the addition of gum arabic (GA) to oral rehydration solution (ORS) enhances water and electrolyte absorption during jejunal perfusion in rats under anesthesia. This study investigates whether GA by oral administration could be equally effective in rats. Isotonic solutions containing 25 g/L GA (AG), or without GA (A0) were administered via oral tube to lightly anesthetized adult female rats. Similar experiments were conducted with hypertonic solutions containing no GA (B0), or either 10 (B10) or 50 g/L GA (B50). Blood concentrations of sodium, glucose, glutamate, zinc, and tritiated water were determined at 0, 15, 30, 60, 90, 120, and 180 minutes, and results between treatments were compared. Administration of the isotonic, GA-containing solution (AG) resulted in a higher blood zinc level than with the isotonic GA-free solution (A0) from 15 minutes throughout 180 minutes. Blood zinc at 15 minutes (means +/- SEM) was as follows: for A0: 69.3 +/- 2.0, for AG: 83.4 +/- 3.5 nmol/L, P=0.002. At 180 minutes, A0: 52.6 +/- 1.8; AG: 68.1 +/- 4.6 nmol/L, P=0.004. The corresponding areas under the curve (AUC) were as follows: for A0: 10,737 +/- 214; for AG: 13,919 +/- 765 nmol x min/L, P<0.001). Glucose, glutamate, sodium, and tritiated water body distribution presented no differences in blood concentrations. For sodium and tritiated water body distribution, there was a significant time effect (P<0.0001). In hypertonic solutions, blood zinc levels declined over time, possibly due to their osmotic, counter-absorptive action, thus obscuring possible opposite effects of GA. GA appears to be an effective enhancer of zinc absorption when orally administered in isotonic solutions to laboratory animals. This proabsorptive capacity could be attributed to some of the physicochemical and biochemical properties of GA and suggest possible applications of GA in liquid formulas and solid food preparations.