Dodecenylsuccinic anhydride derivatives of gum karaya (Sterculia urens): preparation, characterization, and their antibacterial properties

Esterifications of the tree-based gum, gum karaya (GK), using dodecenylsuccinic anhydride (DDSA) were carried out in aqueous solutions. GK was deacetylated using alkali treatment to obtain deacetylated gum karaya (DGK). The DGK and its DDSA derivative were characterized using gel permeation chromatography/multiangle laser light scattering (GPC/MALLS), attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), scanning electron microscopy (SEM), proton nuclear magnetic resonance spectroscopy ((1)H NMR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) analysis, and rheological studies. The degree of substitution was found to be 10.25% for DGK using (1)H NMR spectroscopy. The critical aggregation concentration of DDSA-DGK was determined using dye solubilization and surface tension methods. The antibacterial activity of the DDSA-DGK derivative was then investigated against Gram-negative Escherichia coli and Pseudomonas aeruginosa and Gram-positive Staphylococcus aureus. The DDSA-DGK derivative has the potential for use as a stabilizing agent in food and nonfood applications. It can also be developed as an antibacterial agent.

Karaya root saponin exerts a hypocholesterolemic response in rats fed a high-cholesterol diet

Different sources of saponins are known to have hypocholesterolemic activity with varying degrees of efficacy. We hypothesize that karaya root saponin would efficiently reduce cholesterol. The aim of this study is to examine the comparative hypocholesterolemic effect of karaya root saponin in rats fed a high-cholesterol diet. Sixty male Wister-Imamichi rats were divided into 5 groups of 12 rats each constituting of the following: control group, soybean saponin-supplemented group, karaya root saponin-supplemented group, quillaja saponin-supplemented group, and tea saponin-supplemented group. Compared with the control diet, both the karaya root- and quillaja saponin-supplemented diets significantly reduced (P < .05) serum cholesterol and atherogenic index. Karaya root saponin significantly increased the serum high-density lipoprotein cholesterol, high-density lipoprotein cholesterol/cholesterol ratio, and fecal cholesterol concentrations (P < .05). The triacylglycerol concentration was significantly reduced only in the quillaja saponin-supplemented rats (P < .05). All the tea, soybean, karaya root, and quillaja saponins significantly reduced low-density lipoprotein cholesterol, and the greatest reduction was observed with karaya root saponin. Highest fecal bile acid concentration was found with quillaja saponin, whereas highest liver bile acid concentration was observed with karaya root saponin-supplemented rats (P < .05). These results collectively suggest that karaya root saponin can efficiently reduce serum cholesterol concentration in rats.

Biological activity of some naturally occurring resins, gums and pigments against in vitro LDL oxidation

Naturally occurring gums and resins with beneficial pharmaceutical and nutraceutical properties were tested for their possible protective effect against copper-induced LDL oxidation in vitro. Chiosmastic gum (CMG) (Pistacia lentiscus var. Chia resin) was the most effective in protecting human LDL from oxidation. The minimum and maximum doses for the saturation phenomena of inhibition of LDL oxidation were 2.5 mg and 50 mg CMG (75.3% and 99.9%, respectively). The methanol/water extract of CMG was the most effective compared with other solvent combinations. CMG when fractionated in order to determine a structure-activity relationship showed that the total mastic essential oil, collofonium-like residue and acidic fractions of CMG exhibited a high protective activity ranging from 65.0% to 77.8%. The other natural gums and resins (CMG resin 'liquid collection', P. terebinthus var. Chia resin, dammar resin, acacia gum, tragacanth gum, storax gum) also tested as above, showed 27.0%-78.8% of the maximum LDL protection. The other naturally occurring substances, i.e. triterpenes (amyrin, oleanolic acid, ursolic acid, lupeol, 18-a-glycyrrhetinic acid) and hydroxynaphthoquinones (naphthazarin, shikonin and alkannin) showed 53.5%-78.8% and 27.0%-64.1% LDL protective activity, respectively. The combination effects (68.7%-76.2% LDL protection) of ursolic-, oleanolic- and ursodeoxycholic- acids were almost equal to the effect (75.3%) of the CMG extract in comparable doses.

Vegetable gums modify lectin hemagglutinability

Arabic gum enhances lectin hemagglutinability. The more glycosylated the lectin, the greater the stimulatory effect of the gum. Evidence presented suggests that the interaction between gum and lectin is of a carbohydrate-carbohydrate nature.

Prevention of bacterial adhesion to denture acrylic

A range of non-toxic polysaccharides were screened for their ability to prevent bacterial adhesion to denture acrylic in vitro. Sodium alginate, karaya gum and carrageenan were found to be the most effective, reducing adhesion of Streptococcus salivarius by 98.7, 97.9 and 99.2 per cent respectively. These three polysaccharides were then tested for their ability to reduce the number of bacteria adhering to dentures in vivo. Sodium alginate was the most effective, reducing the attachment of bacteria to the palate-contacting surface of the denture after 5 h of normal wear by 84 per cent compared with uncoated controls. The results of this investigation suggest that the accumulation of denture plaque may be prevented by frequent application of a renewable, sacrificial coating of a non-toxic polysaccharide.

Mineral balance in adult men: effect of four refined fibers

Eleven men consumed a basal diet alone and with cellulose (Na-carboxymethylcellulose, locust bean gum, or karaya gum) added at 7.5 g fiber per 1000 calories for 4 wk each. Food, urine, and fecal composites were collected during the last 8 d of each feeding period. Bowel transit time was not significantly affected; however, total dry fecal weight was significantly increased after the refined fibers compared with that after the basal diet. Adding refined fibers to the basal diet did not significantly affect apparent mineral balance of calcium, magnesium, manganese, iron, copper, or zinc, with the exception of a negative mineral balance for manganese with carboxymethylcellulose. Karaya gum had a mean positive balance for all minerals tested. These results indicate that the hypocholesterolemic effect of the fibers that form gels occurs without compromising mineral balance in those subjects consuming Recommended Dietary Allowance levels of the minerals studied.

Transmission electron microscopy of jejunum, ileum, and caecum tissues from rats fed with gums arabic, karaya and tragacanth

Transmission electron microscopy has been used to study the ultrastructure of rat jejunum, ileum and caecum after dietary supplementation with 10% (w/w) gum arabic, 7% (w/w) gum karaya, 4% (w/w) gum tragacanth for 45 days. Scrutiny of 65 micrographs, undertaken independently by 2 specialists, revealed no abnormalities in any of the organelles in any of the micrographs. Twelve representative micrographs are reproduced here.