Zanthoxylum rhoifolium (Rutaceae) is a plant alkaloid that grows in South America and has been used in Brazilian traditional medicine for the treatment of different health problems. The present study was designed to evaluate the antimicrobial activity of the steam bark crude methanol extract, fractions, and pure alkaloids of Z. rhoifolium. Its stem bark extracts exhibited a broad spectrum of antimicrobial activity, ranging from 12.5 to 100 µg/mL using bioautography method, and from 125 to 500 µg/mL in the microdilution bioassay. From the dichloromethane basic fraction, three furoquinoline alkaloids (1–3), and nine benzophenanthridine alkaloids (4–12) were isolated and the antimicrobial activity of the benzophenanthridine alkaloids is discussed in terms of structure-activity relationships. The alkaloid with the widest spectrum of activity was chelerythrine (10), followed by avicine (12) and dihydrochelerythrine (4). The minimal inhibitory concentrations of chelerythrine, of 1.50 µg/mL for all bacteria tested, and between 3.12 and 6.25 µg/mL for the yeast tested, show this compound to be a more powerful antimicrobial agent when compared with the other active alkaloids isolated from Z. rhoifolium. To verify the potential importance of the methylenedioxy group (ring A) of these alkaloids, chelerythrine was selected to represent the remainder of the benzophenanthridine alkaloids isolated in this work and was subjected to a demethylation reaction giving derivative 14. Compared to chelerythrine, the derivative (14) was less active against the tested bacteria and fungi. Kinetic measurements of the bacteriolytic activities of chelerythrine against the bacteria Bacillus subtilis (Gram-positive) and Escherichia coli (Gram-negative) were determined by optical density based on real time assay, suggesting that its mechanism of action is not bacteriolytic. The present study did not detect hemolytic effects of chelerythrine on erythrocytes and found a protective effect considering the decrease in TBARS and AOPP (advanced oxidized protein products) levels when compared to the control group.
The antimicrobial activity and some constituents of Schinus lentiscifolius are reported for the first time. The results of the present study provide scientific basis for the popular use of Schinus lentiscifolius for a number of different health problems.
Methotrexate (MTX) is a folic acid antagonist used in high doses as an anti-cancer treatment and in low doses for the treatment of some autoimmune diseases. MTX use has been linked to oxidative imbalance, which may cause multi-organ toxicities that can be attenuated by antioxidant supplementation. Despite the oxidative effect of MTX, the influence of antioxidant gene polymorphisms on MTX toxicity is not well studied. Therefore, we analyzed here whether a genetic imbalance of the manganese-dependent superoxide dismutase (SOD2) gene could have some impact on the MTX cytotoxic response. An in vitro study using human peripheral blood mononuclear cells (PBMCs) obtained from carriers with different Ala16Val-SOD2 genotypes (AA, VV and AV) was carried out, and the effect on cell viability and proliferation was analyzed, as well as the effect on oxidative, inflammatory and apoptotic markers. AA-PBMCs that present higher SOD2 efficiencies were more resistance to high MTX doses (10 and 100 µM) than were the VV and AV genotypes. Both lipoperoxidation and ROS levels increased significantly in PBMCs exposed to MTX independent of Ala16Val-SOD2 genotypes, whereas increased protein carbonylation was observed only in PBMCs from V allele carriers. The AA-PBMCs exposed to MTX showed decreasing SOD2 activity, but a concomitant up regulation of the SOD2 gene was observed. A significant increase in glutathione peroxidase (GPX) levels was observed in all PBMCs exposed to MTX. However, this effect was more intense in AA-PBMCs. Caspase-8 and -3 levels were increased in cells exposed to MTX, but the modulation of these genes, as well as that of the Bax and Bcl-2 genes involved in the apoptosis pathway, presented a modulation that was dependent on the SOD2 genotype. MTX at a concentration of 10 µM also increased inflammatory cytokines (IL-1β, IL-6, TNFα and Igγ) and decreased the level of IL-10 anti-inflammatory cytokine, independent of SOD2 genetic background. The results suggest that potential pharmacogenetic effect on the cytotoxic response to MTX due differential redox status of cells carriers different SOD2 genotypes.
Several compounds present in fruits as polyphenols are able to kill or inhibit the growth of microorganisms. These proprieties are relevant mainly in tropical areas, as Amazonian region where infectious are highly prevalent. Therefore, this study investigated the antimicrobial activity of tucumã Amazonian fruit against 37 microorganisms. The potential role of oxidative metabolism imbalance was also studied as causal mechanism of antimicrobial activity. The results showed antibacterial effect of pulp and peel tucumã hydro-alcoholic extracts on three Gram-positive bacteria (Enterococcus faecalis, Bacillus cereus, Listeria monocytogenes) and antifungal effect against Candida albicans. The antimicrobial contribution of main chemical compounds (quercetin, rutin, β-carotene and gallic, caffeic and chlorogenic acids) found in tucumã extracts was also investigated showing an inhibitory effect depending of the organism mainly by quercetin in bacteria and rutin in C. albicans. Analysis of kinetic of DNA releasing in extracellular medium by fluorescence using DNA Pico Green assay(®) and reactive oxygen species production (ROS) showed potential oxidative imbalance contribution on tucumã inhibitory effect. In B. cereus and C. albicans this effect was clear since after 24h the ROS levels were higher when compared to negative control group. In conclusion, tucumã extracts present antimicrobial activity to four microorganisms that have large problems of drug resistance, and the possible mechanism of action of this Amazon fruit is related to REDOX imbalance.
The aim of this study was to investigate whether there is a differential response of lymphocytes from healthy MnSOD genotype subjects to oxidative stress. We used UV radiation as a toxic agent due to its genotoxic effects associated with chromosome aberrations caused by breaks in the DNA strands. Cellular growth rate, cell viability, mitotic index, chromosomal instability and biomarkers of oxidative metabolism were analysed in lymphocyte cells from healthy adults with different Ala16Val MnSOD polymorphisms that produce tree genotypes: AA, VV and AV. We found a differential response to UV exposure in cultures of lymphocyte cells from Ala16Val genotype donors. In general, AA cell cultures presented higher viability and mitotic index and lower TBARS levels than VV and AV cells for both the control and UV exposure groups. However, when we compared the DNA damage among the three genotypes, AA lymphocyte cells presented the highest damage from UV exposure. These data suggest that the Ala16Val polymorphism affects the response of cellular oxidative metabolism in different ways.
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