Stilbenes from Deguelia rufescens var. urucu (Ducke) A. M. G. Azevedo leaves: effects on seed germination and plant growth

The Amazon biodiversity may provide plants whose chemical substances are capable of controlling weeds. In this study we report the isolation and identification of five stilbenes from the leaves of "timbó vermelho" (Deguelia rufescens var. urucu): 4-methoxylonchocarpene (1); 3,5-dimethoxy-4´-hydroxy-3´-prenyl-trans-stilbene (2), lonchocarpene (3), 3,5-dimethoxy-4´-O-prenyl-trans-stilbene (4) and pterostilbene (5). Compounds 2 and 4 are new natural products although 2 has been previously cited as synthesis product. Potential allelopathic activity for 1, 2 and 4 was evaluated over seed germination and plant growth of Mimosa pudica weed. The observed effects on seed germination did not vary significantly (p > 0.05) when the analysis of phytotoxicity was performed with the substances alone, the maximum inhibition did not exceed 20%. The most intense inhibitions on radicle and hypocotyl development were found for compound 4 (p 0,05) quando a análise da fitotoxidade foi realizada com as substâncias isoladamente, cuja inibição máxima não ultrapassou 20%. A inibição mais intensa, quanto ao desenvolvimento da radícula e do hipocótilo, foi encontrada para o composto 4 (p < 0,05). Isoladamente, 4 causou efeito inibitório significativamente maior (p < 0,05) no desenvolvimento da radícula e do hipocótilo, do que 1 e 2. Quando testados aos pares, apresentaram antagonismo para a germinação de sementes e sinergismo para o desenvolvimento da radícula e hipocótilo

Evaluation of the Genotoxic and Antigenotoxic Effects of Andiroba ( Carapa guianensis

The Carapa guianensis (andiroba) oil is commonly used by the Amazon population for medicinal purposes. The objective of this study was to determine the genotoxic and antigenotoxic potential of the andiroba oil (AO) and nanoemulsion (AN) using Swiss mice. Therefore, we used the comet assay and micronucleus test. The AO predominant compounds were oleic (39.13%), palmitic (33.22%), and linoleic (16.86%) acids. AN composition obeyed the surfactant/oil ratio of 0.69, and the Tween 80/Span 80 ratio was held at 0.9. Our results showed no cytotoxicity or genotoxicity in the mice treated with AO and AN alone. However, there was a significant reduction in the polychromatic erythrocytes (PCEs) numbers in all groups treated with doxorubicin (DOX), including those pretreated with AO and AN. Thus, the samples tested did not protect against DOX. On the other hand, our results showed a large increase in micronucleus (MN) formation when the mice were treated with DOX alone; these numbers were reduced when the animals were pretreated with AO and AN. The results indicate a protective effect of andiroba on MN formation and show no evidence of genotoxicity in mice

Fungicidal properties and insights on the mechanisms of the action of volatile oils from Amazonian Aniba trees

The Amazonian Aniba species are world-renowned for their essential oils (EOs). The molecules derived from EOs have been intensively investigated in regards to their potential for disease control in plants. The aim of this study was to investigate the antifungal properties of Aniba canelilla EO (ACEO) and Aniba parviflora EO (APEO) when used against eight phytopathogenic fungi. Gas chromatography-mass spectrometry (GC–MS) analysis of oils showed that 1-nitro-2-phenylethane (∼80%) and linalool (∼40%) are the major compounds in ACEO and APEO, respectively. The ACEO and APEO treatments displayed remarkable antifungal effects against Aspergillus flavus, Aspergillus niger, Fusarium oxysporum, Fusarium solani, Alternaria alternata, Colletotrichum gloeosporioides, Colletotrichum musae and Colletotrichum guaranicola, for which the IC50 values ranged from 0.05 to 0.28 μL mL−1 and 0.17 to 0.63 μL mL−1, respectively. Furthermore, the oil caused the inhibition of conidial germination by at least 83% for ACEO and 78% for APEO. The ACEO and APEO at 5 μL mL−1 induced leakage of nucleic acids and protein, suggesting that inhibition could be linked to the breakdown of membrane integrity of the conidia. In addition, the detection of fluorescent dye propidium iodide (PI) on F. solani conidia treated with ACEO and APEO indicates damage on the conidia cytoplasmic membrane. The findings of this study may be of biotechnological interest for the development of new plant protection products, with the advantage of being less harmful than the agrochemicals currently available. © 2019 Elsevier B.V

Ultrasound-assisted extraction using ethanol efficiently extracted carotenoids from peels of peach palm fruits (Bactris gasipaes Kunth) without altering qualitative carotenoid profile

Peach palm (Bactris gasipaes Kunth) is an amazonian fruit in which its peel has been appointed as a carotenoid-rich byproduct with biological properties. For analytical purposes, carotenoids are frequently extracted by non-green (use of toxic organic solvents) and time-consuming methods, which can affect the quality (carotenoid profile) and safety of extracts for direct food applications. We investigated herein the effect of different extraction methods on the individual carotenoid profile of extracts of peach palm peels by HPLC-DAD. Carotenoid extractions were carried out by maceration in mortar with pestle (with acetone or ethanol), magnetic stirring, shaker and ultrasound-assisted extraction (UAE) using ethanol. UAE provided the highest carotenoid contents (67 mg/100 g), followed by maceration with acetone and ethanol (63 and 52 mg/100 g, respectively), while the lowest contents were observed for the magnetic stirring and shaker extractions (44 mg/100 g), being (all-E)-β-carotene and a Z-isomer of γ-carotene accounted 54–73% of the carotenoid composition. HPLC-DAD data showed the same carotenoid profile regardless the extraction method, yet the percentage of Z-isomers of β-carotene was higher for the shaking (18%), UAE (17%) and magnetic stirring (15%) than for both maceration methods (7 and 8%, with acetone and ethanol, respectively). Thus, the tested extraction methods affected the total carotenoid contents, whereas the chromatographic profile did not change. Furthermore, a carotenoid-rich extract was effectively obtained by using ethanol associated with ultrasound technique (less time-consuming) instead of toxic and non-safe solvents

Minerals evaluation in Amazonian medicinal plants

The Amazonian Brazilian offers an appreciable potential of plants with therapeutic properties, although most are little known. In this way, with the objective of verifying the potentiality nutritional of medicinal herbs, a work was developed to determine the concentration of Ca, Mg, Fe, Cu and Zn in the leaves and in the teas of these species: Piper callosum Ruiz & Pav., Piperaceae, Mikania lindleyana DC., Asteraceae e Arrabidaea chica (Humb. & Bonpl.) B. Verl., Bignoniaceae. After the plants samples have been processed, they were submitted to digestion and soon afterwards the metals were analyzed in an spectrophotometer of Atomic Absorption. The results showed the follow yields: for the tea of Arrabidaea chica Ca were detected (6955 to 20058 mg/L), Mg (2390 to 3094 mg/L) and Fe (40 to 61 mg/L). For the tea of Mikania lindleyana besides the presence of high values of Ca (17722 to 22336 mg/L), Mg (4531 to 9370 mg/L) and Fe (20 to 87 mg/L) they were found from 7 to 16 mg/L of Cu and 9 to 41 mg/L of Zn. The tea of the Piper callosum presented 2036 to 4344 mg/L of Ca, 618 to 4023 mg/L of Mg and 39 to 60 mg/L of Fe. Being compared the results of the minerals with the values recommended by the Health World Organization, is possible that the present metals in the teas of the plants could contribute in the complementation of the people's alimentary diets that use these medicinal plants.Amazônia brasileira oferece um apreciável potencial de plantas com propriedades terapêuticas, embora a maioria seja pouco conhecida. Dessa forma, com o objetivo de verificar a potencialidade nutricional de ervas medicinais, determinou-se a concentração de Ca, Mg, Fe, Cu e Zn nas folhas e nos chás das espécies: Piper callosum Ruiz & Pav., Piperaceae, Mikania lindleyana DC., Asteraceae e Arrabidaea chica (Humb. & Bonpl.) B. Verl., Bignoniaceae. As amostras de plantas depois de terem sido processadas, foram submetidas a digestão e em seguida realizada as leituras dos metais em um espectrofotômetro de absorção atômica. Para o chá de Arrabidaea chica foram detectados teores de Ca (6955 a 20058 mg/L), Mg (2390 a 3094 mg/L) e Fe (40 a 61 mg/L). Para o chá de Mikania lindleyana além da presença de altos valores de Ca (17722 a 22336 mg/L), Mg (4531 a 9370 mg/L) e Fe (20 a 87 mg/L) foram encontrados de 7 a 16 mg/L de Cu e 9 a 41 mg/L de Zn. O chá do Piper callosum apresentou em média 2036 a 4344 mg/L de Ca, 618 a 4023 mg/L de Mg e 39 a 60 mg/L de Fe. Comparando-se os resultados dos minerais com os valores recomendados pela Organização Mundial da Saúde, conclui-se que os metais presentes nos chás das plantas poderiam contribuir na complementação das dietas alimentares das pessoas que as utilizam

In silico analysis of the cyanobacterial lectin scytovirin : new insights into binding properties

We acknowledge Fundação Amazônia de Amparo a Estudos e Pesquisas do Pará (FAPESPA) for financially supporting (ICAAF 099/2014) our project. Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) also supported individual authors through Grant 311686/2015-0 (ECG).Universidade Federal do Pará. Instituto de Ciências Biológicas. Laboratório de Tecnologia Biomolecular. Belém, PA, Brazil.Universidade Federal do Pará. Instituto de Ciências Biológicas. Laboratório de Tecnologia Biomolecular. Belém, PA, Brazil.Universidade Federal do Pará. Instituto de Ciências Exatas e Naturais. Laboratórios de Investigação Sistemática em Biotecnologia e Biodiversidade Molecular. Belém, PA, Brazil.Universidade Federal do Pará. Instituto de Ciências Exatas e Naturais. Laboratórios de Investigação Sistemática em Biotecnologia e Biodiversidade Molecular. Belém, PA, Brazil.Ministério da Saúde. Secretaria de Vigilância em Saúde. Instituto Evandro Chagas. Ananindeua, PA, Brasil.Universidade Federal do Pará. Instituto de Ciências Biológicas. Laboratório de Tecnologia Biomolecular. Belém, PA, Brazil.Scytovirin is a lectin isolated from the cyanobacterium Scytonema varium that has shown activity against HIV, SARS coronavirus and Zaire Ebola virus. Its 95 amino acids are divided into two structural domains (SD), the first spanning amino acids 1–48 (SD1) and the second 49–95 (SD2). Interestingly, the domains are nearly identical but differ in their affinities for carbohydrates. With the aim of enhancing understanding of the binding properties of scytovirin, we performed molecular dynamics (MD) simulations of scytovirin complexed with Man4. We set up three systems: (i) Man4 bound to both domains (SD1+SD2) using the full-length protein; (ii) Man4 bound to an incomplete protein, containing only SD1 and (iii) Man4 bound to an incomplete protein containing only SD2. Contrary to other reports, binding free energy results suggest that Man4 can bind simultaneously to SD1 and SD2 binding regions, but SD1 individually has the best values of energy and the best affinity for Man4. Decomposition of the binding free energy showed that the residues that interact with Man4 were different in the three systems, suggesting that the binding mechanism of Man4 varies between full-length protein, SD1 and SD2. The results presented here may help to formulate strategies to use scytovirin and promote mutagenesis studies to improve the antiviral activity of scytovirin