Physiological concentration of Mg, Cu, and Zn accelerated AGE formation only in glucose-mediated conditions, which was effectively inhibited by chelating ligands. Only quercetin (10) inhibited MGO-mediated AGE formation as well as glucose- and ribose-mediated AGE formation among 10 polyphenols (1-10) tested. We performed an additional structure-activity relationship (SAR) study on flavanols (10, 11, 12, 13, and 14). Morin (12) and kaempherol (14) showed inhibitory activity against MGO-mediated AGE formation, whereas rutin (11) and fisetin (13) did not. These observations indicate that 3,5,7,4'-tetrahydroxy and 4-keto groups of 10 are important to yield newly revised mono-MGO adducts (16 and 17) and di-MGO adduct (18) having cyclic hemiacetals, while 3'-hydroxy group is not essential. We propose here a comprehensive inhibitory mechanism of 10 against AGE formation including chelation effect, trapping of MGO, and trapping of reactive oxygen species (ROS), which leads to oxidative degradation of 18 to 3,4-dihydroxybenzoic acid (15) and other fragments.

Analysis of essential oil of eaglewood tree (Aquilaria agallocha Roxb.) by gas chromatography mass spectrometry BJP

The chemical constituents of leaf and peel essential oil of Citrus medica L. were analysed by gas chromatography mass spectroscopy (GC-MS). Nineteen components accounting for 99.9% of the oil were identified in leaf oil. The major constituents are erucylamide (28.43%), limonene (18.36%) and citral (12.95%). The peel oil contains forty three components accounting for 99.8% of the total oil and the major components are isolimonene (39.37%), citral (23.12%) and limonene (21.78%).

Bacteriocins have become biological weapons against harmful food pathogens and have attracted interest as tools for biopreservation. The aim of this study was to isolate, identify and characterize lactic acid bacterial (LAB) strains from cheese samples, partially purify potential bacteriocins and characterize their antimicrobial activity against pathogens. Bacteriocin-producing organisms were screened by Agar spot assay test. Initially, 25 LAB isolates were isolated from the cheese samples and identified as Lactobacillius spp., among them five strains were able to produce bacteriocin whose antimicrobial activates were analysed by agar-well-diffusion assay test against pathogenic organisms. Bacillus subtilis , Bacillus cereus , Staphylococcus aureus , Streptococcus thermophillus and Listeria monocytogens were inhibited, while Enterococcus faecalis , Salmonella typhi , Escherichia coli and Pseudomonas aeruginosa were resistant to the antimicrobial substances from LAB isolates. For optimal production of bacteriocin, LAB broth cultures were harvested at exponential phase. The molecular weights of the bacteriocins are between 7.0–15.0 kDa. The bacteriocins were characterized on the basis of their sensitivity to heat, pH, enzymes, NaCl and treatments with organic solvents. These results revealed that the bacteriocins from Lactobacillius spp. isolated from the cheese might have potential antimicrobial properties and give new insight in the development of bio-preservative agents to prevent and control pathogenic bacterial infection.

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Serratia rubidaea a member of the Enterobacteriaceae family, is a Gram-negative opportunistic pathogen, known to survive harsh environmental conditions and responsible for hospital associated infections. Specifically, S. rubidaea can withstand desiccation and survive on hospital surfaces and equipments as well as have acquired antimicrobial resistance determinants for different commercial antibiotics. The expansion of this multidrug resistant pattern suggests that the treatment of S. rubidaea infections will become increasingly difficult in near future. Although some measures were taken to control this species, an inhibition mechanism is remaining unknown. To design effective means to control the dissemination of S. rubidaea, an in-depth analysis is required. In the present study, one possible candidate was isolated from the soil of Sundarban Mangroove Forest (Bangladesh) that has important physiological effects to inhibit this pathogenic bacterium. The bacterial isolate was initially identified as Bacillus amyloliquefaciens subsp. amyloliquefaciens using BIOLOG TM identification system and confirmed to be B. amyloliquefaciens strain through 16 S rDNA sequence analysis. The growth and antagonistic activity of this potential strain was shown to be stable under wide range of pH, temperature and salinity (NaCl). Moreover, the novel B. amyloliquefaciens isolate can also inhibit Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and other pathogenic bacteria. These results suggest that B. amyloliquefaciens might have potential antimicrobial properties and further research is required for future use of this bacterium as biological controls of S. rubidaea or development as new drugs for pathogenic bacteria.

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Background The Stevia rebaudiana (Bert.) leaves are natural low-calorie sweeteners that are used in a wide range of products, including foods, drinks, medicines, cosmetics, and more. The current study aims to obtain high-purity stevioside by decolorizing the Stevia leaf extracts with activated charcoal, then purifying them with 70% ethanol, and concentrating them in a rotary evaporator, respectively. Results The yield was then calculated by weighing the crystallized sample following freeze-drying. The average yield is 8.13%. According to High-Performance Liquid Chromatography (HPLC), the purity is 98.12%. The obtained stevioside was compared to standard stevioside and confirmed using Ultra Violet-Visible Spectroscopy (UV-Vis) and Fourier Transform Infrared (FT-IR) spectroscopy. The purified sample showed a wavelength region of 4000–650 cm-1 in FT-IR and UV-Vis spectrum was found at a wavelength of 206.49 nm. An accuracy and precision test was done with a crystal sample, which gave a similar spectrum to the standard stevioside at the same retention time in HPLC. The pH effect on the decolorization of Stevia leaf extracts with activated charcoal was 5.5–8.0. Conclusion In contrast to other commercially available methods, the aforementioned method can be used to purify pure stevioside from Stevialeaf extracts rapidly, simply, and, inexpensively.