Assessment of synergistic antibacterial activity of combined biosurfactants revealed by bacterial cell envelop damage.

Besides potential surface activity and some beneficial physical properties, biosurfactants express antibacterial activity. Bacterial cell membrane disrupting ability of rhamnolipid produced by Pseudomonas aeruginosa C2 and a lipopeptide type biosurfactant, BS15 produced by Bacillus stratosphericus A15 was examined against Staphylococcus aureus ATCC 25923 and Escherichia coli K8813. Broth dilution technique was followed to examine minimum inhibitory concentration (MIC) of both the biosurfactants. The combined effect of rhamnolipid and BS15 against S. aureus and E. coli showed synergistic activity by expressing fractional inhibitory concentration (FIC) index of 0.43 and 0.5. Survival curve of both the bacteria showed bactericidal activity after treating with biosurfactants at their MIC obtained from FIC index study as it killed >90% of initial population. The lesser value of MIC than minimum bactericidal concentration (MBC) of the biosurfactants also supported their bactericidal activity against both the bacteria. Membrane permeability against both the bacteria was supported by amplifying protein release, increasing of cell surface hydrophobicity, withholding capacity of crystal violet dye and leakage of intracellular materials. Finally cell membrane disruption was confirmed by scanning electron microscopy (SEM). All these experiments expressed synergism and effective bactericidal activity of the combination of rhamnolipid and BS15 by enhancing the bacterial cell membrane permeability. Such effect of the combination of rhamnolipid and BS15 could make them promising alternatives to traditional antibiotic in near future.

Protective efficacy of ursodeoxycholic acid nanoparticles in animal model of inflammatory bowel disease.

UNLABELLED: Abstract Context: Ursodeoxycholic acid (UDCA) exerts dose-dependent chemoprevention in colonic inflammation. Polycationic UDCA nanoparticles (UNPs) are envisaged for solubility enhancement and site directed drug delivery. OBJECTIVE: The objective was to study the ameliorative efficacy of UNPs through localized delivery of the drug. METHODS: UNPs were prepared through nanoprecipitation technique. Particle size, morphology, in vitro drug release and in vivo protective efficacy in inflammatory bowel disease (IBD) of these nanoparticles were studied. RESULTS AND DISCUSSION: The average particle size was around 100 nm, and the average drug encapsulation was about 99%. In vitro drug release study shows optimal drug release in simulated colonic fluid. The lowering of tissue nitric oxide, malondialdehyde, myeloperoxidase and histology of the colon tissue supported the protective efficacy of the nanoparticles. CONCLUSION: This study presents the improved efficacy of UNPs in animal model of IBD due to complete release of drug at the desired site of action.

Accentuated transdermal application of glucosamine sulphate attenuates experimental osteoarthritis induced by monosodium iodoacetate.

Osteoarthritis is a chronic degenerative joint disease causing pain and disability. Glucosamine sulphate is a well known oral supplement for its treatment. The present pioneering study provides an overview of the accentuated transdermal delivery of glucosamine sulphate through the optimized gel formulation with guar gum and sodium carboxymethyl cellulose (Na-CMC). Response surface methodology based on the three-level three-factor central composite design provided the optimum concentration of guar gum, Na-CMC and glycerol for a maximum flux. The transdermal characterization, ex vivo permeation study and in vivo study were performed with optimized gel formulation. The factorial design predicted the optimum values of guar gum, Na-CMC and glycerol which were 418.53 mg, 444.97 mg and 2322.4 mg respectively for 25 g of the gel. This optimized gel demonstrated the maximum flux, i.e., 1047.46 µg cm-2 h-1. The optimized gel showed satisfactory results with respect to drug uniformity, pH, stability, rheological properties, zeta potential, drug-excipient compatibility and skin irritation. The release of the drug from the optimized transdermal gel followed the controlled first order Fickian (non-steady) release pattern. The in vivo study was carried out in a rat model of osteoarthritis induced by monosodium iodoacetate damaging the tibial plateau. In this study the optimized formulation effectively reduced the symptoms like reduction in swelling of the knee joint, gross changes in digitized radio images and morphological and histopathological alterations. Additionally the changes in the release pattern of the proinflammatory cytokine tumor necrosis factor-α illustrated the efficacy of the transdermal gel for the treatment of experimental osteoarthritis. Thus the optimized gel was found to be a unique potential vehicle for transdermal application of glucosamine sulphate which effectively attenuates the experimental osteoarthritis.

Biodegradation of waste lubricants by a newly isolated Ochrobactrum sp. C1.

A potential degrader of paraffinic and aromatic hydrocarbons was isolated from oil-contaminated soil from steel plant effluent area in Burnpur, India. The strain was investigated for degradation of waste lubricants (waste engine oil and waste transformer oil) that often contain EPA (Environmental Protection Agency, USA) classified priority pollutants and was identified as Ochrobactrum sp. C1 by 16S rRNA gene sequencing. The strain C1 was found to tolerate unusually high waste lubricant concentration along with emulsification capability of the culture broth, and its degradation efficiency was 48.5 ± 0.5 % for waste engine oil and 30.47 ± 0.25 % for waste transformer oil during 7 days incubation period. In order to get optimal degradation efficiency, a three level Box-Behnken design was employed to optimize the physical parameters namely pH, temperature and waste oil concentration. The results indicate that at temperature 36.4 °C, pH 7.3 and with 4.6 % (v/v) oil concentration, the percentage degradation of waste engine oil will be 57 % within 7 days. At this optimized condition, the experimental values (56.7 ± 0.25 %) are in a good agreement with the predicted values with a calculated R 2 to be 0.998 and significant correlation between biodegradation and emulsification activity (E 24 = 69.42 ± 0.32 %) of the culture broth toward engine oil was found with a correlation coefficient of 0.972. This is the first study showing that an Ochrobactrum sp. strain is capable of degrading waste lubricants, which might contribute to the bioremediation of waste lubricating oil-contaminated soil.