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.
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.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.