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Background: Saline stress is an important environmental factor that limits the productivity of numerous agricultural crops, such as onion (Allium cepa L.), a vegetable present in gardens and used in various ways. Pulegone has been identified as a component that has a large number of biological functions. Objective: The aim of this study was to investigate the effect of pulegone (100 and 500 μg/mL) on the morphological and biochemical changes to onions induced by stressing seeds with NaCl. Method: Soil composition, emergence percentage and its inhibition, emergence speed index (ESI), leaf and root parameters, malondialdehyde (MDA) content, free iron content and chelation/oxidation capacity (Fe2+) were measured following 120 days of treatment. Results: Pulegone was able to significantly improve the changes in ESI caused by saline stress, not restoring other emergence parameters. The leaf size was also improved by the pulegone, which did not affect the morphological changes of the roots. Conclusion: Our results suggest that the use of pulegone is a viable treatment to mitigate the effects of salt stress on A. cepa seeds.

Mercury chloride (HgCl2) acts as a bioaccumulator capable of causing numerous neurological and physiological changes in organisms in a negative way. However, rutin has been considered a very effective antioxidant compound in the treatment of neurodegenerative diseases, as it can neutralize radicals capable of damaging neuronal cells. In this context, this study aimed to evaluate rutin as a neoprotective agent against the damage induced by HgCl2 in Drosophila melanogaster. The exposure of the flies to the agents was carried out in triplicate, and about 150 adult flies were evaluated. To assess the antioxidant action of rutin, MTT, phenanthroline, nitric oxide, total thiols and NPSH tests were carried out in the following concentrations: Control (1500 μL of distilled water), 1 mg/g of HgCl2, 0.5 mg/g of Rutin + HgCl2, 1 mg/g of Rutin + HgCl2, 2 mg/g of Rutin + HgCl2. The locomotion test was verified by negative geotaxis, the result of which showed that flies exposed to HgCl2 had difficulties in flight. The group treated with HgCl2 alone had a high mortality rate, while in combination with different concentrations of rutin, it heard a moderate reduction in the number of deaths, as well as in the negative geotaxis data in which the rutin had a positive effect. An increase in iron (II) levels was observed at the highest concentrations of rutin, while at low concentrations, rutin significantly decreased nitric oxide levels. The HgCl2 + R group (2 mg/g) showed a significant increase in the total thiols content, while for the NPSH all rutin concentrations showed a significant increase in the levels of non-protein thiols. Our results demonstrate that mercury chloride can cause oxidative stress in D. melanogaster. However, the results suggest that rutin has antioxidant and protective effects against the damage caused by HgCl2.

Mercury (Hg) is widely distributed in the environment and is known to produce several adverse effects in organisms. The aim of the present study was to examine the in vitro antioxidant activity and Hg chelating ability of the hydroalcoholic extract of Psidium guajava leaves (HEPG). In addition, the potential protective effects of HEPG against Hg(II) were evaluated using a yeast model (Saccharomyces cerevisiae). HEPG was found to exert significant antioxidant activity in 2,2-diphenyl-1-picrylhydrazyl scavenger and inhibition of lipid peroxidation induced by Fe(II) assays in a concentration-dependent manner. The extract also exhibited significant Hg(II) chelating activity. In yeast, Hg(II) induced a significant decrease in cell viability. In contrast, HEPG partially prevented the fall in cell viability induced by Hg(II). In conclusion, HEPG exhibited protective effects against Hg(II)-mediated toxicity, which may be related to both antioxidant and Hg(II)-chelating activities.

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.

This study aimed to determine the chemical profile of the essential oil obtained from the leaves of C. verbenacea DC and to evaluate its antibiotic and antibiotic-modifying activity by the gaseous contact method of the essential oil and its major component. The essential oil was analyzed by GC-MS. Chemical analysis identified a predominance of sabinene (31.99%), β-caryophyllene (13.10%), bicyclogermacrene (11.06%), germacrene-D (7.44%) and (+) spathulenol (6.53%). The essential oil and sabinene exhibited no antibacterial activity according to the method used. Sabinene combined with all antibiotics showed synergism against S. aureus and the essential oil showed indifference when combined with aminoglycosides. We demonstrated that sabinene has statistically significant antibiotic-modifying activity against S. aureus, indicating this compound as a new alternative pharmaceutical source in fighting infections by Gram-positive bacteria.

Eugenia uniflora L. (Myrtaceae family), also known as “pitanga”, is a tree species widely used in popular medicine. Despite the well documented beneficial effects of the extracts and essential oils from this plant, little is known about its toxicity. We performed a phytochemical fingerprinting and evaluated the toxicity induced by the Eugenia uniflora leaves essential oil in a Drosophila melanogaster model. In order to understand the biochemical mechanisms involved in E. uniflora essential oil toxicity, changes in the Nrf2 signaling as well as the hallmarks of oxidative stress were measured. The exposure of adult flies to the essential oil via a fumigant method resulted in increased mortality and locomotor deficits. In parallel, an oxidative stress response signaling, evidenced by changes in ROS production, lipid peroxidation, alterations in the activity of antioxidant enzymes and expression of Nrf2 protein targets occurred. In the light of our findings, attention is drawn to the indiscriminate use of this plant for medicinal purposes. In addition, a potential bio-insecticidal activity of Eugenia uniflora volatile compounds is suggested, a fact that needs to be further explored.

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.

Objective: To evaluate the antibacterial activity and neuroprotective capacity of the ethanolic and aqueous extracts of Tarenaya spinosa (T. spinosa) as well as to determine and quantify some of its polyphenols by high performance liquid chromatography with diode-array detection (HPLC-DAD). Methods: The bacterial Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa strains, grown in Heart Agar Infusion, were tested. The drugs gentamicin, norfloxacin and imipenem were used to evaluate the modulating or antagonistic capacity of the T. spinosa extracts. The extract was analysed by HPLC-DAD to determine the main phenolic compounds. For the cell viability tests, individual heads of the Nauphoeta cinerea arthropod model were removed, homogenized in Trifluoromethyl ketone and centrifuged afterwards. Subsequently, 20 μL of NaNO2 were added to the biological material, except in the control group, to evaluate the protection capacity of the extracts. The homogenate of the insect heads was incubated for 2 h in tubes containing tetrazolium bromide. Results: HPLC-DAD demonstrated that the ethanolic extract of T. spinosa presented caffeic acid as the major compound. The ethanolic extract also showed neuroprotective effects at concentrations ≥ 10 μg/mL, while aqueous extract was shown to have a protective effect only at the concentration of 100 μg/mL. The aqueous extract demonstrated a clinically relevant antibacterial activity against the Staphylococcus aureus multidrug resistant strain - MDR, with MIC 512 μg/mL. However, when the extracts were associated with gentamicin and imipenem, a synergism was detected against Staphylococcus aureus and Escherichia coli MDR strains. Conclusions: Although it does not present an antibacterial action, the extracts of T. spinosa can be used in the pharmaceutical industries since its extracts show modulating action of drugs. Besides, these natural products have neuroprotective capacity.

Objetivo: Estudos recentes apontam a utilização de plantas na forma de sucos ou chás como fontes de agentes antioxidantes naturais que apresentam baixo risco podendo ser utilizado no auxílio do tratamento de várias doenças. Material e métodos: Neste contexto, avaliaram-se os potenciais antioxidantes, in vitro, dos extratos de Eugenia uniflora e Psidium sobraleanum, além de quantificar fenóis e flavonoides presentes nos extratos. Resultados: De acordo com os resultados obtidos, observou-se uma melhor atividade antioxidante para o extrato de Eugenia uniflora, para o teste de TBARS com fosfolipídio de ovo, os extratos reduziram os níveis basais no processo de peroxidação lipídica, e quando induzidos por Fe2+ o extrato de Psidium sobraleanum mostrouse mais eficiente. Conclusões: Portanto, através destes ensaios pode-se verificar que os extratos das folhas das espécies, Eugenia uniflora e Psidium sobraleanum, apresentam uma atividade antioxidante, diretamente relacionada com substâncias fenólicas produzidas a partir do seu metabolismo secundário. Objetivo: Estudios recientes reportan la utilización de plantas en forma de zumos o te como fuente de agentes antioxidantes naturales que presentan bajo riesgo, pudiendo ser utilizados como complemento del tratamiento de diversas enfermedades. Materiales y métodos: En este contexto, se evaluaran in vitro, los potenciales antioxidantes, de los extractos de Eugenia uniflora y Psidium sobraleanum, además de cuantificar fenoles y flavonoides presentes en los extractos. Resultados: De acuerdo con los resultados obtenidos, se observó una mejor actividad antioxidante con el extracto de Eugenia uniflora, en el test de TBARS con fofolipidos de huevo, los extractos redujeron los niveles basales en el proceso de peroxidación lipídica; y cuando fue inducida con Fe+2, el extracto de Psidium sobraleanum se mostró más eficiente. Conclusiones: Por lo tanto, a través de estos ensayos se pudo comprobar que los extractos de las hojas de las especies Eugenia uniflora y Psidium sobraleanum presentan actividad antioxidante, directamente relacionada con sustancias fenólicas producidas a partir de sus metabolitos secundarios. Objective: Evaluation of antioxidant activity has been an important issue considering its importance in human health. Recent studies show that the use of plants in the form of juices or teas as sources of natural antioxidants with low risk can be used as an aid to the treatment of various diseases. Material and Methods: Evaluation of the antioxidant potential in vitro, extracts of Eugenia uniflora and Psidium sobraleanum, as well as the quantification of phenols and flavonoids present in the extracts. Results: Findings showed a better antioxidant activity for the extract of Eugenia uniflora. In the TBARS test with egg phospholipids, extracts presented a reduction in the basal levels in the lipid peroxidation process; and when the Fe2 + extract was inducted, Psidium sobraleanum proved to be more efficient.. Conclusions: These tests proved that the extracts of leaves of the species Eugenia uniflora and Psidium sobraleanum present antioxidant activity which is directly related to phenolic substances produced in its secondary metabolism.

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