Structural analysis of a water insoluble polysaccharide from pearl millet and evaluating its prebiotic activity.

Epidemiological studies have shown an inverse correlation between dietary intake of prebiotics and the risk of chronic diseases. Pearl millet is a potential economic source to develop a new class of prebiotics in the form of its polysaccharide. In the present study, the chemical structure of a water insoluble homopolysaccharide (PMG), and its prebiotic properties were investigated. The structure of PMG was elucidated on the basis of total hydrolysis, methylation analysis, and 1D/2D NMR (1H, 13C, DEPT-135, HSQC, DQF-COSY, NOESY and ROESY) experiments. The results indicated that PMG was a glucan with an average molecular weight ~ 361 kDa having a backbone of (1 â†’ 3) α-d-glucopyranosyl residues. Hydrolysis of PMG by salivary and pancreatic α amylase was 1.75 % ± 0.34 and 1.99 % ± 0.18 respectively. A positive prebiotic score of PMG with both L. acidophilus and L. brevis (0.446 ± 0.031 & 0.427 ± 0.016) hints towards its prebiotic potential. These observations suggest that PMG might be used as a potential prebiotic component in the food and pharmaceutical applications.

Protective Role of Black Tea Flavonoids Against Ethanol-Induced Gastropathy via Matrix Metalloproteinase Pathway.

ABSTRACT: Tea polyphenols are known to prevent various ailments like cancer, atherosclerosis, hypertension and diabetes. Our study aimed at to decipher the gastroprotective effect of aqueous black tea extract (BTE) against ethanol-induced gastric damage and the role of BTE in modulating MMP-9 activity and expression, both in vivo and in vitro. The protective role of BTE was assessed in Sprague-Dawley rats after inducing damage with 70% ethanol. Human gastric adenocarcinoma cells (AGS) were treated with ethanol in ex vivo experiment. MMP-9 activity and expression were investigated through gelatin zymography and western blotting. Reactive oxygen species (ROS) generation was also studied by fluorescence spectroscopy and confocal microscopy, with or without treatment of BTE both in vivo and in vitro experiments. In addition, the effect of citric acid treated BTE (cBTE), which mimics lemon tea, was examined on ethanol-induced gastropathy. BTE exhibited antiulcer activity through reduction of glutathione depletion, lipid peroxidation, protein oxidation, ROS production and inflammatory cell infiltration in rat gastric tissues. In addition, BTE significantly inhibited synthesis and secretion of proMMP-9 both in vivo and in vitro. The mitochondrial enzymes succinate dehydrogenase and NADH oxidase in rat gastric tissues were downregulated by BTE while protecting gastric ulcer. Citric acid addition to BTE was observer to enrich the lead compound, catechin. Interestingly, cBTE showed higher anti-ulcer activity than the untreated one. BTE shows protective role against ethanol-induced gastric ulcer in rats through scavenging ROS and downregulating proMMP-9 activity. While cBTE shows better protection due to enrichment of catechin and removal of tannins in tea extract leading to enhanced inhibitory role on proMMP-9 activity and ROS production.

Determination of pH-dependent antioxidant activity of palm (Borassus flabellifer) polyphenol compounds by photoluminol and DPPH methods: a comparison of redox reaction sensitivity.

Palm juice (Borassus flabellifer) is one of the most common and cheap natural juices. Fermented palm juice contains various phytochemical compounds that exhibit antioxidant activity. In the present study, we examined the effects of pH on the production of phytochemicals and their antioxidant activity during the fermentation process. The concentration of total phenolics and flavonoid compounds of fermented palm juice and their antioxidant activity were investigated at various pH. The results showed that total phenolics concentration and antioxidant activity of palm wine and palm vinegar increase as pH increases: 3.5 < 4.5 < 5.5. Maximum flavonoid concentration was obtained at pH 6.5. Measurements of antioxidant activity by conventional DPPH method and Photochem antioxidant analyzer technique were highly correlated, with a corresponding R 2 value of 0.94.

Development of porous lamellar poly(L-lactic acid) scaffolds by conventional injection molding process.

A novel fabrication technique is proposed for the preparation of unidirectionally oriented, porous scaffolds by selective polymer leaching from lamellar structures created by conventional injection molding. The proof of the concept is implemented using a 50/50 wt.% poly(L-lactic acid)/poly(ethylene oxide) (PLLA/PEO) blend. With this composition, the PLLA and PEO blend is biphasic, containing a homogeneous PLLA/PEO phase and a PEO-rich phase. The two phases were structured using injection molding into well-defined alternating layers of homogeneous PLLA/PEO phase and PEO-rich phase. Leaching of water-soluble PEO from the PEO-rich phase produces macropores, and leaching of phase-separated PEO from the initially homogeneous PLLA/PEO phase produces micropores in the lamellae. Thus, scaffolds with a macroporous lamellar architecture with microporous walls can be produced. The lamellae are continuous along the flow direction, and a continuous lamellar thickness of less than 1 microm could be achieved. Porosities of 57-74% and pore sizes of around 50-100 microm can be obtained using this process. The tensile elastic moduli of the porous constructs were between 580 and 800 MPa. We propose that this organic-solvent-free method of preparing lamellar scaffolds with good mechanical properties, and the reproducibility associated with the injection molding technique, holds promise for a wide range of guided tissue engineering applications.

Dynamic mechanical behavior of starch-based scaffolds in dry and physiologically simulated conditions: effect of porosity and pore size.

The three-dimensional scaffolds of a blend of starch and poly(L-lactic) acid, SPLA70, were produced using compression molding of polymer/salt mixture followed by leaching of salt. One series of scaffolds were prepared with varying polymer-to-salt ratio while keeping the salt size constant, and the other series of scaffolds were prepared with varying salt sizes while keeping the polymer-to-salt ratio constant. The X-ray microcomputed tomography and scanning electron microscopy assay were used to analyze the porous morphologies, porosity and distribution of porosity of the porous scaffolds. Salt-free and integrated SPLA70 scaffolds with porosities ranging from 74% to 82% and pore sizes of 125-250 to 500-1000 microm can be fabricated using the present fabrication technique. The water uptake of the SPLA70 scaffolds increases with increasing porosities and also with increasing pore size. In dry state, the storage modulus decreases with increasing porosity and also with increasing pore size. The normalized modulus values are related to normalized density of the scaffolds by a power-law function with an exponent between 2 and 3. For the immersed scaffolds under physiological conditions, the storage modulus was less dependent on porosity and pore size. However, the loss factor increased significantly compared with dry state measurements. The present study clearly shows that the mechanical performance of porous polymeric constructs in dry and in immersed state is completely different, and for comparison with biomechanical performance of tissues, the tests should ideally be performed in immersed state.