Melanoidin, a food protein-derived advanced maillard reaction product, suppresses Helicobacter pylori in vitro and in vivo

BACKGROUND: Extracellular urease proteins located on the surface of Helicobacter pylori are gastric mucin-targeted adhesins, which play an important role in infection and colonization to the host. In this study we have determined the inhibitory activity of a variety of melanoidins, protein-derived advanced Maillard reaction products, ubiquitously found in heat-treated foods, on urease-gastric mucin adhesion. In addition, we have determined the anticolonization effect of melanoidin I, prepared by the Maillard reaction between casein and lactose, in an animal model and in human subjects infected with this bacterium. METHODS: The inhibitory activity of each compound was determined by a competitive binding assay of labeled gastric mucin to plate-immobilized urease. Melanoidin I was used in an in vivo trial using euthymic hairless mice as an infection model. Melanoidin I was consumed for 8 weeks by subjects infected with H. pylori. The [(13)C] urease breath test and H. pylori-specific antigen in the stool (HpSA) test were performed on subjects at week 0 and week 8. RESULTS: A variety of food protein-derived melanoidins strongly inhibited urease-gastric mucin adhesion in the concentration range of 10 micro g/ml to 100 micro g/ml. In particular, melanoidin I significantly (p <.05) suppressed colonization of H. pylori in mice when given for 10 weeks via the diets. Eight weeks daily intake of 3 g melanoidin I significantly (p <.05) decreased the optical density of HpSA in subjects. CONCLUSION: Foods containing protein-derived melanoidins may be an alternative to antibiotic-based therapy to prevent H. pylori that combines safety, ease of administration and efficacy.     

Six new constituents from the roots of Erythrina variegata

Three new isoflavonoids, eryvarins M-O (1-3), two new 2-arylbenzofurans, eryvarins P and Q (4 and 5), and a new 3-aryl-2,3-dihydrobenzofuran, eryvarin R (6), together with three known compounds, were isolated from the roots of Erythrina variegata. The structures of these compounds were established by spectroscopic analysis. Eryvarin R (6) is an unusual 3-aryl-2,3-dihydrobenzofuran derivative with a formyl (CHO) group. Eryvarin Q (5) showed potent antibacterial activity against methicillin-resistant Staphylococcus aureus.     

Identification of a novel locus that regulates expression of toxin genes in Clostridium perfringens

A novel gene that regulates the alpha-toxin (plc), kappa-toxin (colA), and theta;-toxin (pfoA) genes was identified using toxin-negative mutant strains of Clostridium perfringens. The cloned 3.2-kb fragment contained the virX gene encoding a 51-amino acid polypeptide of unknown function that seemed to be responsible for the activation of toxin genes. The virX knock out mutant of wild-type strain 13 showed a reduced expression of the plc, colA, and pfoA genes, which was complemented by the transformation of the intact virX gene. Deletion and site-directed mutagenesis studies suggested that the virX gene acts as a regulatory RNA rather than as a peptide regulator. The virX locus found in this study might play a part in the signal transduction to regulate toxin production in C. perfringens.     

Synergistic effect of deoxyanthocyanins from symbiotic fern Azolla spp. on hrmA gene induction in the cyanobacterium Nostoc punctiforme

The hrmA gene of the N2-fixing cyanobacterium Nostoc punctiforme functions in repressing the formation of transitory motile filaments, termed hormogonia, by plant-associated vegetative filaments. Here, we report that anthocyanins can contribute to induction of hrmA expression. Aqueous extract from fronds of the fern Azolla pinnata, a host of symbiotic Nostoc spp., was found to be a potent inducer of hrmA-luxAB in N. punctiforme strain UCD 328. The hrmA-luxAB inducing activities of A. pinnata, as well as Azolla filiculoides, were positively correlated with levels of frond deoxyanthocyanins. Analyses of the deoxyanthocyanins in frond extracts revealed, in order of predominance, an acetylated glycoside derivative of luteolinidin (m/z 475) and of apigeninidin (m/z 459) and minor amounts of a second luteolinidin derivative. At up to 150 microM, a purified preparation of deoxyanthocyanins only weakly induced hrmA-luxAB on its own, but mixtures with hrmA-luxAB inducers (A. filiculoides extract or the flavonoid naringin) synergistically doubled to tripled their inducing activities. These results suggest that appropriately localized deoxyanthocyanins could function in plant-mediated mechanisms for repressing Nostoc spp. hormogonium formation.     

Peroxynitrite scavenging activities of aromatic compounds isolated from Konnyaku,Amorphophallus konjac K.Koch

(+/-)-5,5'-Dimethoxysesamin, erythrinasinate, indole-3-carbaldehyde, (7R,8S)-dihydrodehydrodiconiferyl alcohol 9-O-beta-D-glucopyranoside, cis- and trans-N-(p-coumaroyl)serotonin, serotonin, 3,4-dihydroxybenzoic acid, and 3,4-dihydroxybenzaldehyde have been found in tobiko, a food by-product, and evaluation of their peroxynitrite scavenging activities has been done. Among these compounds, serotonin, trans-N-(p-coumaroyl)serotonin, 3,4-dihydroxybenzaldehyde, and 3,4-dihydroxybenzoic acid showed stronger activities than that of BHT (butylated hydroxytoluene) at 200 microM.     

Total DNA preparation excluding extracellular acidic polysaccharide from Lipomyces yeasts and its application to taxonomic studies

A preparation method of total DNA from Lipomyces yeasts was improved in order to exclude extracellular acidic polysaccharide thoroughly. The method combined an ultracentrifuge and polyethylene glycol precipitation with the usual method. The total DNAs obtained were analyzed for G + C content and by DNA-DNA hybridization. The results all agreed almost completely with literature data. All the DNA samples prepared using this method were pure enough for these taxonomic analyses and could also be used as templates of PCR for amplification of small subunit ribosomal DNA and the internal transcribed spacer region.     

The production of hydrogen sulfide is regulated by testosterone and S-adenosyl-L-methionine in mouse brain

Hydrogen sulfide (H2S) is endogenously produced in the brain from L-cysteine by the enzyme cystathionine beta-synthase (CBS) and functions as a neuromodulator in the brain. H2S selectively enhances NMDA receptor-mediated responses and alters hippocampal long-term potentiation (LTP). The production of H2S is regulated by Ca2+/calmodulin-mediated pathways and is enhanced in response to neuronal excitation. In addition to this fast regulation, we describe here a slower form of the regulation of H2S production by testosterone and S-adenosyl-L-methionine (SAM), a CBS activator. Endogenous H2S in the mouse brain increases after birth, reaches a maximum level at 8 weeks and then decreases. Female brain contains less H2S than male brain at each age. A single administration of testosterone to female mice increases the endogenous H2S and SAM, which reach levels similar to those of male mice. In contrast, castration of male mice decreases the levels of testosterone, SAM and H2S in the brain. Administration of SAM once a day for 3 days increases the brain H2S without significantly changing the testosterone level. These observations suggest that testosterone can regulate the brain H2S level via changing the level of SAM.