Characterization and Evaluation of Filmogenic, Polymeric, and Biofilm Suspension Properties of Cassava Starch Base (Manihot esculenta Crantz) Plasticized with Polyols / Caracterização e Avaliação das Propriedades Filmogénicas, Poliméricas e de Suspensão de Biofilme da Base de Amido de Mandioca (Manihot esculenta Crantz) Plastificado com Polióis

This study investigated the gelatinization process of polymeric suspensions of cassava starch (Manihot esculenta Crantz) plasticized with glycerol or ethylene glycol and used for biofilm production. Scanning electron microscopy confirmed that the starch, used as raw material for suspensions, consists of granule-forming clods and granular aggregates. Physical parameters such as viscosity, density, and temperature can be evaluated and used to accurately characterize and identify the gelatinization point of the polyol-plasticized starch. Upon reaching the gelatinization point, the suspensions went underwent retrogradation and had a kinetic viscosity of 19 to 23.508 mPa·s for the starch–glycerol suspension and 13.56 to 16.12 mPa·s for the starch–ethylene glycol suspension. However, the density of the suspensions slightly decreased during this process, ranging from 1.01 to 0.98 g/cm3. The starch–glycerol biofilm was more malleable and resistant, while the starch–ethylene glycol biofilm was inflexible and brittle. The use of different polyols facilitated the modification of the solubilization capacity of the biofilms. The starch–glycerol biofilm had a solubility value three times higher than that of the starch–ethylene glycol biofilm. Keywords: Biofilms, starch, polyols, gelatinization, crystallinity. RESUMOEste estudo investigou o processo de gelatinização de suspensões poliméricas de amido de mandioca (Manihot esculenta Crantz) plastificado com glicerol ou etileno glicol e utilizado na produção de biofilme. A microscopia eletrônica de varredura confirmou que o amido, usado como matéria-prima para suspensões, consiste em torrões formadores de grânulos e agregados granulares. Parâmetros físicos como viscosidade, densidade e temperatura podem ser avaliados e utilizados para caracterizar e identificar com precisão o ponto de gelatinização do amido poliol plastificado. Ao atingir o ponto de gelatinização, as suspensões foram submetidas a retrogradação e tiveram uma viscosidade cinética de 19 a 23,508 mPa · s para a suspensão de amido-glicerol e 13,56 a 16,12 mPa · s para a suspensão de amido-etileno-glicol. No entanto, a densidade das suspensões diminuiu ligeiramente durante esse processo, variando de 1,01 a 0,98 g / cm3. O biofilme de amido-glicerol era mais maleável e resistente, enquanto o biofilme de amido-etileno-glicol era inflexível e quebradiço. O uso de diferentes polióis facilitou a modificação da capacidade de solubilização dos biofilmes. O biofilme de amido-glicerol apresentou um valor de solubilidade três vezes maior que o do biofilme de amido-etileno-glicol. This study investigated the gelatinization process of polymeric suspensions of cassava starch (Manihot esculenta Crantz) plasticized with glycerol or ethylene glycol and used for biofilm production. Scanning electron microscopy confirmed that the starch, used as raw material for suspensions, consists of granule-forming clods and granular aggregates. Physical parameters such as viscosity, density, and temperature can be evaluated and used to accurately characterize and identify the gelatinization point of the polyol-plasticized starch. Upon reaching the gelatinization point, the suspensions went underwent retrogradation and had a kinetic viscosity of 19 to 23.508 mPa·s for the starch–glycerol suspension and 13.56 to 16.12 mPa·s for the starch–ethylene glycol suspension. However, the density of the suspensions slightly decreased during this process, ranging from 1.01 to 0.98 g/cm3. The starch–glycerol biofilm was more malleable and resistant, while the starch–ethylene glycol biofilm was inflexible and brittle. The use of different polyols facilitated the modification of the solubilization capacity of the biofilms. The starch–glycerol biofilm had a solubility value three times higher than that of the starch–ethylene glycol biofilm.

Volatile Compounds, Chemical Composition and Biological Activities of <em>Apis mellifera</em> Bee Propolis

Propolis is a wax-like resin collected by bees from tree shoots and/or other botanical sources that is used as glue to seal cracks or open spaces in the hive. Its color varies from green to brown and reddish, depending on its botanical origin. Among the substances that can be found in propolis, low molecular weight compounds, such as monoterpenes and sesquiterpenes are the most common. Several biological activities are attributed to these classes of substances, such as antifungal, antibacterial, and others. The objective of this work was to evaluate the chemical composition of volatile compounds present in propolis samples and to analyze their correlation with biological activities

Invasive Species in the Amazon

One of the main reasons for environmental disturbances such as declination in pasture productivity and biodiversity losses is the high infestation of herbaceous weeds, generally referred to as “Juquira” in the Amazon region. If they are not adequately controlled, such infestation might lead to degradation of pasture, resulting in complete loss of productivity and subsequent abandonment of the area. In this sense, this chapter aims to describe the main invasive species present in the Amazon region, as well as to characterize both the old and innovative techniques of use in agriculture, in large and small scale, for the control of agricultural pests

Molecular Modeling Approaches Can Reveal the Molecular Interactions Established between a Biofilm and the Bioactive Compounds of the Essential Oil of Piper divaricatum

Molecular modeling approaches are used in a versatile way to investigate the properties of diverse organic and inorganic structures such as proteins, biomolecules, nanomaterials, functionalized nanoparticles, and membranes. However, more detailed studies are needed to understand the molecular nature of interactions established in gelatin biofilms impregnated with bioactive compounds. Because of this, we used computational methods to evaluate how the major compounds of Piper divaricatum essential oil can interact with the gelatin biofilm structure. For this, we used as inspiration the paper published, where various properties of the essential oil impregnated gelatin biofilm P. divaricatum are reported. After our computer simulations, we related our molecular observations to biofilm&rsquo;s structural and mechanical properties. Our results suggest that the major compounds of the essential oil were able to interrupt intermolecular interactions between the chains of the biofilm matrix. However, the compounds also established interactions with the amino acid residues of these chains. Our molecular analyses also explain changes in the structural and mechanical properties of the essential oil-impregnated biofilm. These results can support the planning of functional packaging impregnated with bioactive compounds that can protect food against microorganisms harmful to human health

Molecular Modeling Approaches Can Reveal the Molecular Interactions Established between a Biofilm and the Bioactive Compounds of the Essential Oil of <em>Piper divaricatum</em>

Molecular modeling approaches are used in a versatile way to investigate the properties of diverse organic and inorganic structures such as proteins, biomolecules, nanomaterials, functionalized nanoparticles, and membranes. However, more detailed studies are needed to understand the molecular nature of interactions established in gelatin biofilms impregnated with bioactive compounds. Because of this, we used computational methods to evaluate how the major compounds of Piper divaricatum essential oil can interact with the gelatin biofilm structure. For this, we used as inspiration the paper published, where various properties of the essential oil impregnated gelatin biofilm P. divaricatum are reported. After our computer simulations, we related our molecular observations to biofilm’s structural and mechanical properties. Our results suggest that the major compounds of the essential oil were able to interrupt intermolecular interactions between the chains of the biofilm matrix. However, the compounds also established interactions with the amino acid residues of these chains. Our molecular analyses also explain changes in the structural and mechanical properties of the essential oil-impregnated biofilm. These results can support the planning of functional packaging impregnated with bioactive compounds that can protect food against microorganisms harmful to human health

Naphthoquinones isolated from Eleutherine plicata herb: in vitro antimalarial activity and molecular modeling to investigate their binding modes

CAPES; CNPqUniversidade Federal do Pará. Instituto Ciências da Saúde. Programa de Pós-Graduação em Inovação Farmacêutica. Belém, PA, Brazil.Universidade Federal do Pará. Instituto de Tecnologia. Belém, PA, Brazil.Ministério da Saúde. Secretaria de Vigilância em Saúde. Instituto Evandro Chagas. Ananindeua, PA, Brasil.Ministério da Saúde. Secretaria de Vigilância em Saúde. Instituto Evandro Chagas. Ananindeua, PA, Brasil.Universidade Federal do Pará. Instituto Ciências da Saúde. Programa de Pós-Graduação em Inovação Farmacêutica. Belém, PA, Brazil / Universidade Federal do Pará. Instituto de Tecnologia. Belém, PA, Brazil.Universidade Federal do Pará. Instituto Ciências da Saúde. Programa de Pós-Graduação em Inovação Farmacêutica. Belém, PA, Brazil.Plasmodium falciparum is the cause of malaria and has become resistant to the drugs used to treat the disease. Therefore, the development for novel compounds with antimalarial activity has become urgent. Plant species, such as naphthoquinone-rich Eleutherine plicata, may provide novel substances that exhibit antimalarial activity and serve as an alternative for the treatment of this disease. From this plant species, ethanol extracts were obtained, fractionated, and the isolated substances eleutherin, and isoleutherin were characterized by nuclear magnetic resonance. There in vitro activity against Plasmodium falciparum was examined using the traditional Microtest method using the extract, fractions, and isolated molecules. Eleutherin and isoleutherin showed the best activity toward the parasite with IC50 values of 10.45 and 8.70 µg/mL, respectively. Characterization of the binding mode of the compounds with a target enzyme and identification of the molecular interactions were revealed via molecular docking results. Eleutherin and isoeleutherin interacted with highly conserved residues from the binding cavity of the cytochrome bc1 complex, a protein found in mitochondria. Therefore, the eleutherin and isoeleutherin naphthoquinones showed antiplasmodial activity with a similar mechanism to that of atovaquone were able to interact with the cytochrome bc1 complex, and showed promise for antimalarial treatments

Effects of Drying Temperature and Solvents on In Vitro Diabetic Wound Healing Potential of <i>Moringa oleifera</i> Leaf Extracts

The delayed healing of wounds among people with diabetes is a severe problem worldwide. Hyperglycemia and increased levels of free radicals are the major inhibiting factors of wound healing in diabetic patients. Plant extracts are a rich source of polyphenols, allowing them to be an effective agent for wound healing. Drying temperature and extraction solvent highly affect the stability of polyphenols in plant materials. However, there is a need to optimize the extraction protocol to ensure the efficacy of the final product. For this purpose, the effects of drying temperature and solvents on the polyphenolic composition and diabetic wound healing activity of Moringa oleifera leaves were examined in the present research. Fresh leaves were oven dried at different temperatures (10 °C, 30 °C, 50 °C, and 100 °C) and extracted in three solvents (acetone, ethanol, and methanol) to obtain twelve extracts in total. The extracts were assessed for free radical scavenging and antihyperglycemic effects using DPPH (2,2-diphenylpicrylhydrazyl) and α- glucosidase inhibition assays. Alongside this, a scratch assay was performed to evaluate the cell migration activity of M. oleifera on the human retinal pigment epithelial cell line. The cytotoxicity of the plant extracts was assessed on human retinal pigment epithelial (RPE) and hepatocellular carcinoma (Huh-7) cell lines. Using high-performance liquid chromatography, phenolic compounds in extracts of M. oleifera were identified. We found that an ethanol-based extract prepared by drying the leaves at 10 °C contained the highest amounts of identified polyphenols. Moringa oleifera extracts showed remarkable antioxidant, antidiabetic, and cell migration properties. The best results were obtained with leaves dried at 10 °C and 30 °C. Decreased activities were observed with drying temperatures of 50 °C and above. Moreover, M. oleifera extracts exhibited no toxicity on RPE cells, and the same extracts were cytotoxic for Huh-7 cells. This study revealed that M. oleifera leaves extracts can enhance wound healing in diabetic conditions due to their antihyperglycemic, antioxidant, and cell migration effects. The leaves of this plant can be an excellent therapeutic option when extracted at optimum conditions

In Silico Evaluation of the Antimicrobial Activity of Thymol&mdash;Major Compounds in the Essential Oil of Lippia thymoides Mart. &amp; Schauer (Verbenaceae)

In this paper, we evaluated the drug-receptor interactions responsible for the antimicrobial activity of thymol, the major compound present in the essential oil (EO) of Lippia thymoides (L. thymoides) Mart. &amp; Schauer (Verbenaceae). It was previously reported that this EO exhibits antimicrobial activity against Candida albicans (C. albicans), Staphylococcus aureus (S. aureus), and Escherichia coli (E. coli). Therefore, we used molecular docking, molecular dynamics simulations, and free energy calculations to investigate the interaction of thymol with pharmacological receptors of interest to combat these pathogens. We found that thymol interacted favorably with the active sites of the microorganisms&rsquo; molecular targets. MolDock Score results for systems formed with CYP51 (C. albicans), Dihydrofolate reductase (S. aureus), and Dihydropteroate synthase (E. coli) were &minus;77.85, &minus;67.53, and &minus;60.88, respectively. Throughout the duration of the MD simulations, thymol continued interacting with the binding pocket of the molecular target of each microorganism. The van der Waals (&Delta;EvdW = &minus;24.88, &minus;26.44, &minus;21.71 kcal/mol, respectively) and electrostatic interaction energies (&Delta;Eele = &minus;3.94, &minus;11.07, &minus;12.43 kcal/mol, respectively) and the nonpolar solvation energies (&Delta;GNP = &minus;3.37, &minus;3.25, &minus;2.93 kcal/mol, respectively) were mainly responsible for the formation of complexes with CYP51 (C. albicans), Dihydrofolate reductase (S. aureus), and Dihydropteroate synthase (E. coli)

Chemical Composition and Preliminary Toxicity Evaluation of the Essential Oil from Peperomia circinnata Link var. circinnata. (Piperaceae) in Artemia salina Leach

Peperomia Ruiz and Pav, the second largest genus of the Piperaceae, has over the years shown potential biological activities. In this sense, the present work aimed to carry out a seasonal and circadian study on the chemical composition of Peperomia circinata essential oils and aromas, as well as to evaluate the preliminary toxicity in Artemia salina Leach and carry out an in silico study on the interaction mechanism. The chemical composition was characterized by gas chromatography (GC/MS and GC-FID). In the seasonal study the essential oil yields had a variation of 1.2&ndash;7.9%, and in the circadian study the variation was 1.5&ndash;5.6%. The major compounds in the seasonal study were &beta;-phellandrene and elemicin, in the circadian they were &beta;-phellandrene and myrcene, and the aroma was characterized by the presence of &beta;-phellandrene. The multivariate analysis showed that the period and time of collection influenced the essential oil and aroma chemical composition. The highest toxicity value was observed for the essential oil obtained from the dry material, collected in July with a value of 14.45 &plusmn; 0.25 &mu;g&middot;mL&minus;1, the in silico study showed that the major compounds may be related to potential biological activity demonstrated by the present study

Essential Oils from Annonaceae Species from Brazil: A Systematic Review of Their Phytochemistry, and Biological Activities

The present work involves a systematic review of the chemical composition and biological effects of essential oils from the Annonaceae species collected in Brazil from 2011 to 2021. Annonaceae is one of the most important botanical families in Brazil, as some species have economic value in the market as local and international fruit. In addition, the species have useful applications in several areas—for instance, as raw materials for use in cosmetics and perfumery and as medicinal plants. In folk medicine, species such as Annona glabra L. and Xylopia sericea A. St.-Hil. are used to treat diseases such as rheumatism and malaria. The species of Annonaceae are an important source of essential oils and are rich in compounds belonging to the classes of mono and sesquiterpenes; of these compounds, α-pinene, β-pinene, limonene, (E)-caryophyllene, bicyclogermacrene, caryophyllene oxide, germacrene D, spathulenol, and β-elemene are the most abundant. The antimicrobial, anti-inflammatory, antileishmania, antioxidant, antiproliferative, cytotoxic, larvicidal, trypanocidal, and antimalarial activities of essential oils from the Annonaceae species in Brazil have been described in previous research, with the most studies on this topic being related to their antiproliferative or cytotoxic activities. In some studies, it was observed that the biological activity reported for these essential oils was superior to that of drugs available on the market, as is the case of the essential oil of the species Guatteria punctata (Aubl.) R. A. Howard., which showed a trypanocidal effect that was 34 times stronger than that of the reference drug benznidazol