Inhibition of metabolism of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone by dietary benzaldehydes

Biocatalytic valorization of lignin subunit: Screening a carboxylic acid reductase with high substrate preference to syringyl functional group

Lignin is inexpensive and the most abundant source of biological aromatics. It can be decomposed to three types of subunits, 4-hydroxybenzoic, vanillic and syringic acids, each of which can be valorized to value added compounds. Syringaldehyde is a versatile phenolic aldehyde implicated with multiple bioactive properties as well as intermediates for biofuels. Herein, fourteen microbial carboxylic acid reductases (CARs) were screened for the biocatalysis of the energetically unfavorable reduction of syringic acid to syringaldehyde. Nine CARs were positive to syringic acid reduction, among which Mycobacterium abscessus CAR exhibited the highest analytical yield of the product. By the optimization of the reaction condition, the whole-cell biocatalyst (i.e., recombinant Escherichia coli expressing the gene) successfully converted syringic acid to syringaldehyde with a yield of 90%. Furthermore, structural features of the screened CAR responsible for the specificity toward the syringyl subunit were analyzed that helps to further engineer the biocatalyst for improved performances.

Phytochemicals and potential health effects of Sambucus williamsii Hance (Jiegumu)

Sambucus williamsii Hance (Jiegumu) is traditionally used in Chinese medicine to treat bone and joint diseases. The major phytochemicals in S. williamsii are lignans, terpenoids, and phenolic acids, together with trace amounts of essential oils, minerals, amino acids, and natural pigments. In this review, a database search for studies published from 1990 to November 2015 was conducted using PubMed, the China Academic Journals Full-Text Database, and Google Scholar with the keywords “Sambucus williamsii Hance”, “Sambucus williamsii”, “Sambucuswilliamsii + clinic”, “Sambucuswilliamsii + biology”, “Sambucuswilliamsii + chemicals”, and “Jiegumu”, which covered chemical studies, cell culture studies, animal experiments, and clinical studies. This article reviewed the compounds isolated from S. williamsii that may reduce the risk of cancer, and exert antifungal, antioxidant, anti-inflammatory, bone fracture healing, and antiosteoporotic effects.

Effects of artichoke (Cynara scolymus) leaf and bloom head extracts on chemically induced DNA lesions in Drosophila melanogaster

The genotoxicity of bloom head (BHE) and leaf (LE) extracts from artichoke (Cynara scolymus L.), and their ability to modulate the mutagenicity and recombinogenicity of two alkylating agents (ethyl methanesulfonate - EMS and mitomycin C - MMC) and the intercalating agent bleomycin (BLM), were examined using the somatic mutation and recombination test (SMART) in Drosophila melanogaster. Neither the mutagenicity nor the recombinogenicity of BLM or MMC was modified by co- or post-treatment with BHE or LE. In contrast, co-treatment with BHE significantly enhanced the EMS-induced genotoxicity involving mutagenic and/or recombinant events. Co-treatment with LE did not alter the genotoxicity of EMS whereas post-treatment with the highest dose of LE significantly increased this genotoxicity. This enhancement included a synergistic increase restricted to somatic recombination. These results show that artichoke extracts promote homologous recombination in proliferative cells of D. melanogaster.

Effect of vanillin on toxicant-induced lethality in the Drosophila melanogaster DNA repair test

Vanillin (VA) modulates the genotoxicity of chemical and physical agents in a complex manner. Previous studies indicate that VA inhibits the mutagenicity but increases the mitotic homologous recombination caused by at least some genotoxic agents. In the present study, we have evaluated the effects of VA on the repair of lethal damage produced by three genotoxins, N-ethyl-N-nitrosourea (ENU), ethyl methanesulfonate (EMS), and mitomycin C (MMC), using the DNA repair test (DRT) in Drosophila melanogaster. VA, 0.25% and 0.5% (w/v), increased the toxicity of MMC and EMS in repair-deficient flies, as measured by a decrease in the proportion of male to female progeny in the DRT; sex ratios decreased from 18-48% for MMC and 21-97% for EMS. These effects may be caused by the inhibition of nonhomologous DNA end joining caused by VA. In contrast to the results with MMC and EMS, VA protected against the lethality of ENU in repair-defective flies, as measured by a 43-207% increase in the survival of male flies in the DRT. It was inferred that the protective effect was due to VA modulating stages prior to the induction of ENU lesions in DNA, including modulating the antioxidant properties of VA and/or to its interference with the metabolic activation and/or detoxification of specific genotoxins. The results from this study indicate that the characterization of VA as a promising agent for preventing damage to genes and chromosomes should be tempered by observations that VA can increase the toxicity of chemical agents.

Vanillin as a modulator agent in SMART test: Inhibition in the steps that precede N-methyl-N-nitrosourea-, N-ethyl-N-nitrosourea-, ethylmethanesulphonate- and bleomycin-genotoxicity

Vanillin (VA), the world's major flavoring compound used in food industry and confectionery products - that has antimutagenic and anticarcinogenic activity against a variety of mutagenic/carcinogenic agents - was tested for the interval between the formation of premutational lesion and it is finalization as a DNA lesion. The overall findings using co-treatment protocols in SMART test suggest that VA can lead to a significant protection against the general genotoxicity of ethylmethanesulphonate (EMS), N-ethyl-N-nitrosourea (ENU), N-methyl-N-nitrosourea (MNU) and bleomycin sulphate (BLEO). Considering MNU, ENU and EMS the desmutagenic activity observed could result from VA-stimulation of detoxification, via induction of glutathione S-transferase. However, the protector effect related to BLEO could be attributed to its powerful scavenger ability, which has the potential to prevent oxidative damage induced by BLEO.

The synergistic effects of vanillin on recombination predominate over its antimutagenic action in relation to MMC-induced lesions in somatic cells of Drosophila melanogaster

The wing Somatic Mutation And Recombination Test (SMART) in Drosophila melanogaster was used to study the modulating action of vanillin (VA) in combination with the alkylating agents mitomycin C (MMC), methylmethanesulphonate (MMS) and the bifunctional nitrogen mustard (HN2). Two types of treatments with VA and each of the three genotoxins were performed: chronic co-treatments of three-day-old larvae of the standard cross as well as post-treatments after acute exposure with the genotoxins. This allowed the study of the action of VA not only in the steps that precede the induction of DNA lesions but also in the repair processes. The overall findings from the co-treatment series suggest that ingestion of VA with MMS or MMC can lead to significant protection against genotoxicity; but this is not the case with HN2. Antioxidant activity, suppression of metabolic activation or interaction with the active groups of these two alkylating agents could be mechanisms by means of which VA exerts its desmutagenic action. In contrast, when evaluated in the post-treatment procedure, VA causes two antagonistic effects on the genotoxicity of MMC: (i) synergism on recombination (172.8%) and (ii) protection against mutation (79.0%). Consequently, both activities together lead to a considerable increase in mitotic recombination. In spite of being separate events, recombination and gene mutation are correlated during mitosis since the fate of a DNA lesion depends on the repair pathway followed. Our results may suggest that VA is a modifying factor that blocks the mutagenic pathway and consequently directs the MMC-induced lesions into a recombinational repair. Furthermore, VA did not modify the genotoxicity when administered after treatments with HN2 or MMS. Therefore, the major finding of the present study, namely the co-recombinagenic activity of VA on MMC-induced lesions, seems to be related to the type of induced lesion and consequently to the repair processes involved in its correction.

2,4-Nonadienal and benzaldehyde bioantimutagens in Fushimi sweet pepper (Fushimi-togarashi)

Fushimi sweet pepper, "Fushimi-togarashi", is one of the "Kyo-yasai", traditional vegetables, in Kyoto, Japan. The chloroform fraction of Fushimi sweet pepper showed bioantimutagenicity on UV induced mutation in Escherichia coli B/r WP2. The bioantimutagen was purified with silica gel chromatography and identified as 2, 4-nonadienal (ID(50) = 20 microg/plate) on the basis of GC retention time and EI-MS spectrum of authentic 2,4-nonadienal. The sweet pepper also contained a known bioantimutagen, benzaldehyde (ID(50) = 2 mg/plate). Additive bioantimutagenicity was also observed by 2, 4-nonadienal with benzaldehyde. 2,4-Nonadienal did not show bioantimutagenicity in an UV excision repair deficient strain, E. coli B/r WP2s uvrA(-)(). Furthermore no delay of the first cell division after UV irradiation was observed in E. coli B/r WP2. These results indicate that the bioantimutagenic activity of 2, 4-nonadienal on UV mutagenesis might depend on the excision repair system in E. coli B/r WP2.