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Mercury is a heavy metal that does not present any biological function and is considered toxic since it offers great environmental contamination risks to human beings. Psidium brawnianum is a plant found in the town of Araripe, in the Ceara State of Brazil, and is commonly known as “araca de veado” – guava tree. The current study has the aim to determine the cytoprotective and metal chelating effect of P. brownianum extract. The results show that the tested HgCl2 concentrations damage the germination and development of Lactuta sativa (lettuce) seeds. However, when sub-allelopathic concentrations (128 μg/mL) of the extract are used in association with HgCl2, a cytoprotective effect can be observed in assayed bacterial and plant models which correlated to metal chelation by phyrocompounds from the extract. Thus, the current study shows that this plant may be an interesting source of products against the heavy metal toxicity problem and contamination.

Introduction The objective of this study was to evaluate the antibacterial activity of methanol (MFEECC) and ethyl acetate (AFEECC) fractions, obtained from the ethanol extract of Croton campestris A. leaves. Methods Antibacterial and modulating activity (on bacterial resistance) was determined by micro dilution method to identify the MIC (Minimum Inhibitory Concentration), performed in triplicate and statistical significance tested by ANOVA (two-way) with Bonferroni post hoc test ( p Results In the antibacterial activity tests the fractions showed a MIC of ≥1024 μg/mL. In regards to modulation of bacterial resistance, MFEECC showed synergism when combined with antibiotic against bacterial strains. In the modulation tests, AFEECC potentiated the effects of amikacin against Staphylococcus aureus and Pseudomonas aeruginosa but had an antagonistic effect against Escherichia coli . AFEECC combined with gentamicin displayed antagonism against S. aureus and E. coli and an antagonistic effect against P. aeruginosa. When AFEECC was combined with Neomycin it resulted in antagonism against P. aeruginosa but did not affect S. aureus and E. coli . Conclusions The results indicate that the extracts and fractions obtained from C. campestris leaves could represent an alternative source of natural products capable of modifying and interfering with bacterial resistance to aminoglycosides.

The fruit fly Drosophila melanogaster is often utilized in genetic research, and in the last decades, it has become one of best organisms for studies of human diseases and toxicological research. Mercury chloride (HgCl 2 ), the main representative of mercury compounds, is the target of numerous investigations, not only because of its intrinsic toxicity but also because it accounts for the toxicity of elemental mercury since the latter is converted to Hg +2 by oxidation. Eugenia jambolana Lam. Myrtaceae, known in Brazil as “jambolao”, is of great interest because of its medicinal applications, especially its leaves and fruits. The aim of this work was to characterize, by CG–MS, the chemical constituents of the essential oil of Eugenia jambolana and to evaluate its bioinsecticidal action in the Drosophila melanogaster model, as well as to determine the cytoprotective and chelating effect of the extract of E. jambolana . The results obtained here point to the potential of essential oils as a source in biological prospecting for bioinsecticides. Because of their biodegradability, essential oils can be important tools in the biological control of pests. The results demonstrated that the extract has an allelopathic effect on lettuce seeds and that its interaction with mercury chloride allows a greater growth of the radicle and plumule of Lactuta sativa seedlings, showing that this plant can provide an alternative solution to the problem of contamination by heavy metals, besides having cytoprotective potential and moderate chelating activity.

The development of new drugs from plants is an interesting alternative approach to overcoming microbial resistance. Passiflora cincinnata shows resistance to diseases and pests and a higher concentration of chemical components that may be useful in the pharmaceutical industry. We investigated the potential antimicrobial and antibiotic-modifying activity of hydroalcoholic extracts of leaves, stems, bark, pulp and seeds of P. cincinnata. The extracts were prepared by homogenization of material in 50% ethanol. Minimum inhibitory concentration (MIC) was determined by the broth dilution method, and the bacterial strains tested were Staphylococcus aureus and Escherichia coli. Antibiotic-modifying activity was evaluated against the strains S. aureus 03 and E. coli 08, using a subinhibitory concentration of extract. The antibiotics tested were: amikacin, gentamicin, ampicillin, potassium benzylpenicillin and oxacillin. The extracts did not show antimicrobial activity of clinical relevance, where the MIC was equal to or greater than 1024μg/mL. S. aureus showed 13 events, while E. coli showed only 4 events. Among these events, 14 involved synergistic activity, potentiating the effect of the antibiotics, and only 3 events demonstrated antagonistic activity toward ampicillin. Hydroalcoholic extracts are potential antimicrobial agents when combined with conventional drugs little utilized in in vivo treatment.

Environmental stressors such as mercury are important for the search of substances to lower induced oxidative damage. Accordingly, secondary metabolites from plants with antioxidant activity represent an interesting alternative. The aim of this work was to evaluate the cytoprotective effect of the ethanol extract of Eugenia uniflora against mercury chloride. The main antioxidant phytochemicals were quantified by HPLC. The chelating effect was evaluated using the O-phenanthroline method. The cytoprotective effect was assayed using bacterial and plant models. The cytotoxic and the negative geotaxis effect was determined using Drosophila melanogaster. The ethanol extract of E. uniflora demonstrated chelating effect against iron, and these results can be related to the total phenols (1079 mg/g) and flavonoids (946.9 mg/g), detected by HPLC and quantified. The same extract demonstrated a cytoprotective effect in both models and a non-toxic effect against D. melanogaster, with low mortality and low inhibition of geotaxis, demonstrating that the extract can reduce the toxicity of this heavy metal against prokaryotic and Eukaryotic organisms. Due the results, we can conclude that the phytocompounds in the ethanol extract of E. uniflora, possibly phenols and flavonoids, could be interesting agents to protect different organisms against the heavy metal damages by a chelating or an antioxidative mechanism. Other studies are still necessary; however, these findings can open a new perspective to the recuperation of environments contaminated by heavy metals. Keywords: Mercurium chloride, Negative geotactic effect, Chelating effect, Cytoprotection, Heavy metal