Influence of drying temperature on coconut-fibers.

The use of natural fibers in cementitious composites has been gaining prominence in engineering. The natural lignocellulosic fibers (NLFs) used in these composites have advantages such as reduced density, reduced fragmentation and concrete cracking, thus improving flexural performance and durability. Coconut-fiber is one of those natural fibers and its use presents technical, ecological, social and economic benefits, as it is improperly disposed of, representing a large waste of natural resources, in addition to causing environmental pollution.. Thus, composites reinforced with natural fibers are promising materials for the construction industry, as in addition to meeting the sustainability of buildings, there will also be a reduction in urban solid waste generated and gains for structures with the use of environmentally friendly materials that meet to active efforts and with greater durability. This work aims to evaluate the tensile behavior of green coconut-fibers subjected to different drying temperatures through chemical, thermal (TG/DSC), morphological, visual and mechanical analysis. Drying temperatures of 70 °C, 100 °C and 130 °C were analyzed and the results indicated that the drying temperature at 70 °C was satisfactory, providing fiber-reinforced composites with good tensile strength, combined with good ductility.

Mineral Content, Antioxidant Activity and Essential Oil of Allophylus edulis (A. St.-Hil., A. Juss. & Cambess.) Radlk. Leaves: Plant from South American Biodiversity.

Allophylus edulis (A. St.-Hil., A. Juss. & Cambess.) Radlk. (Sapindaceae) is an edible plant from the South American biodiversity that is a potential source of bioactive compounds. The mineral content and antioxidant activity of Allophylus edulis leaves were investigated, as well as the composition and the antioxidant activity of the essential oil. The mineral content was determined by ICP - OES and the antioxidant assays were assessed by ABTS, DPPH and FRAP. The essential oil was obtained by hydrodistillation and analyzed by GC/MS. Calcium, potassium, phosphorus, sulfur, and magnesium were the main minerals found in A. edulis leaves. Of the toxic metals that were present, a low level of aluminum was detected. The essential oil of A. edulis has (E)-nerolidol as major compound and both, the leaves, and the essential oil isolated from the leaves have antioxidant potential. These findings could provide a framework for developing new food and non-food products with A. edulis leaves.

Development, characterization and antimicrobial activity of sodium dodecyl sulfate-polysaccharides capsules containing eugenol.

This work describes the production of polysaccharide multilayer capsules to control the release of Eugenol (Eug) and enabling its use as an antimicrobial agent. For this propose, oil-in-water nanoemulsions of sodium dodecyl sulfate were coated with alternating depositions of chitosan and carboxymethylcellulose using the Layer-by-Layer (LbL) technique, resulting in capsules containing 1-5 layers. The average size ranged from 188 ±â€¯30 (LbL1) to 1415 ±â€¯517 nm (LbL5). The maximum incorporation efficiency was 70.8 ±â€¯2.7 % for Eug-SDS-LbL1. The initial burst releases decreased in proportion to the increase in the number of polysaccharide layers (22.3 ±â€¯3.1 %-12.8 ±â€¯1.6 %), and are influenced by the pH. These systems exhibited antifungal activity against Aspergillus niger, Trichoderma sp, Gliocladium sp, and Candida albicans, and Eug minimum inhibitory concentrations were lower as compared to those of the free agent. Therefore, these capsules represent promising antifungal materials for application in various fields.

Olfactory response of Mahanarva spectabilis (Hemiptera: Cercopidae) to volatile organic compounds from forage grasses.

Several herbivorous insects utilize plant chemical cues to identify hosts for feeding. The role of smell in host plant detection by Mahanarva spectabilis (Distant) remains largely unknown. In this study, assays were applied to assess M. spectabilis olfactory responses to forage grasses (Pennisetum purpureum cvs. Roxo Botucatu and Pioneiro; Panicum maximum cvs. Makueni and Tanzânia; Hyparrhenia rufa cv. Jaraguá; Melinis minutiflora; Cynodon dactylon cv. Tifton; Brachiaria brizantha cv. Marandú; and Brachiaria decumbens cv. Basilisk). Bioassays were performed using a Y-olfactometer to evaluate the behavior of adult M. spectabilis to forage damaged and undamaged by insects. M. spectabilis preferred volatiles of undamaged Basilisk and Pioneiro. Repellent behavior by M. spectabilis to cospecifics was recorded for plant volatiles from damaged Marandú. The mixture of volatiles from undamaged forage grasses differed from that of forage grasses damaged by insects. Forage grasses showed a greater diversity of compounds after damage, including menthone, eucalyptol and camphor, which are compounds likely to cause loss of attractiveness or repellence. Our results demonstrate that M. spectabilis employs plant chemical cues in its choice of hosts. This fact may contribute to strategies of integrated management against this pest.

Guaianolide sesquiterpene lactones and aporphine alkaloids from the stem bark of Guatteria friesiana.

Three guaianolide sesquiterpenes, denoted guatterfriesols A-C, and four aporphine alkaloid derivatives were isolated from the stem bark of the Amazonian plant Guatteria friesiana. Thus far, sesquiterpene lactones have not been described in Annonaceae. Structures of the previously undescribed compounds were established by using 1D and 2D NMR spectroscopy in combination with MS. The absolute stereochemistry was assigned via NOE NMR experiments, ECD spectroscopy, and theoretical calculations using the TDDFT approach. Among the isolated compounds, the alkaloid guatterfriesidine showed anti-glycation activity by inhibiting the formation of advanced glycation end-products (AGEs) through the prevention of oxidation in both BSA/methylglyoxal and BSA/fructose systems.

In vitro Antiproliferative and Antibacterial Activities of Essential Oils from Four Species of Guatteria.

The essential oils (EOs) extracted from four species of the genus Guatteria, G. australis, G. ferruginea, G. latifolia, and G. sellowiana were analyzed. A total of 24, 22, 25, and 19 constituents of the oils from four species, respectively, were identified by GC/MS. These oils showed qualitative and quantitative differences. All the oils contained the oxygenated sesquiterpenes spathulenol (11.04 - 40.29%) and caryophyllene oxide (7.74 - 40.13%) as predominant constituents. Evaluation of antiproliferative activity of the EOs showed strong selectivity (1.1 - 4.1 µg/ml) against the tumor cell line OVCAR-03 (ovarian cancer), i.e., more active than the positive control doxorubicin (11.7 µg/ml). All EOs showed strong antibacterial activity (minimum inhibitory concentrations of 0.062 - 0.25 mg/ml) against strains of Rhodococcus equi.

Evaluation of larvicidal activity and ecotoxicity of linalool, methyl cinnamate and methyl cinnamate/linalool in combination against Aedes aegypti.

The frequent use of synthetic pesticides to control Aedes aegypti population can lead to environmental and/or human contamination and the emergence of resistant insects. Linalool and methyl cinnamate are presented as an alternative to the synthetic pesticides, since they can exhibit larvicidal, repellent and/or insecticidal activity and are considered safe for use. The aim of this study was to evaluate the larvicidal activity of methyl cinnamate, linalool and methyl cinnamate/linalool in combination (MC-L) (1:4 ratio, respectively) against Aedes aegypti. The in vitro preliminary toxicity through brine shrimp lethality assay and hemolytic activity, and the phytotoxic potential were also investigated to assess the safety of their use as larvicide. Methyl cinnamate showed significant larvicidal activity when compared to linalool (LC50 values of 35.4µg/mL and 275.2µg/mL, respectively) and to MC-L (LC50 138.0µg/mL). Larvae morphological changes subjected to the specified treatments were observed, as the flooding of tracheal system and midgut damage, hindering the larval development and survival. Preliminary in vitro toxicity through brine shrimp showed the high bioactivity of the substances (methyl cinnamate LC50 35.5µg/mL; linalool LC50 96.1µg/mL) and the mixture (MC-L LC50 57.7µg/mL). The results showed that, despite the higher larvicidal activity of methyl cinnamate, the use of MC-L as a larvicide seems to be more appropriate due to its significant larvicidal activity and low toxicity.

7,7-Dimethylaporphine and Other Alkaloids from the Bark of Guatteria friesiana.

Phytochemical investigation of the bark of Guatteria friesiana afforded 12 new aporphines (1-12), along with nine known alkaloids (13-21). The structures of the new alkaloids were determined on the basis of spectroscopic data interpretation. The cytotoxic activity of the isolated compounds against a small panel of tumor cell lines was assessed using the Alamar blue assay.

Palladium-Catalyzed Direct α-Aryation of Benzyl Thioethers with Aryl Bromides.

The arylation of sp3-hybridized C-H's bonds is a powerful strategy to build molecular complexity and diversity. A novel and efficient palladium-catalyzed direct sp3 C-H arylation of aryl and alkyl benzyl thioether derivatives with aryl bromides is reported. The reaction involves reversible deprotonation of the benzylic C-H's of the thioether with either LiN(SiMe3)2 or NaN(SiMe3)2 and subsequent cross-coupling to provide the functionalized products in up to 97% yield. A screen of 24 of the most successful ligands in cross-coupling chemistry led to the identification of NiXantPhos as the only viable ligand for this challenging coupling.

Essential Oils from Different Plant Parts of Eucalyptus cinerea F. Muell. ex Benth. (Myrtaceae) as a Source of 1,8-Cineole and Their Bioactivities.

Eucalyptus cinerea, known as silver dollar tree, has few descriptions in traditional medicine. Chemical composition and antimicrobial properties of the essential oils of leaves, flowers and fruits, collected seasonally, were determined by GC/MS and disk diffusion/MIC, respectively. 1,8-Cineole was the main compound, particularly in fresh leaves-Spring (74.98%), dried leaves-Spring (85.32%), flowers-Winter (78.76%) and fruits-Winter (80.97%). Other compounds were found in the aerial parts in all seasons: α-pinene (2.41% to 10.13%), limonene (1.46% to 4.43%), α-terpineol (1.73% to 11.72%), and α-terpinyl acetate (3.04% to 20.44%). The essential oils showed antimicrobial activities against bacteria and yeasts, with the best results being found for the dried autumn and winter leaves oils (MIC < 0.39 mg/mL) against Streptococcus pyogenes. For the other tested microorganisms the following MIC results were found: Staphylococcus aureus-Dried leaves oil from summer (0.78 mg/mL), Pseudomonas aeruginosa-Flowers oil from autumn and fruits oil from winter (1.56 mg/mL) and Candida albicans-Flowers oil from autumn and fruits oils from winter and spring (0.78 mg/mL).

7,7-Dimethylaporphine alkaloids from the stem of Guatteriopsis friesiana.

Phytochemical investigation of a methanolic extract of the stem of Guatteriopsis friesiana afforded two new 7,7-dimethylaporphine alkaloids, 6,6a-dihydrodemethoxyguadiscine (1) and guatteriopsiscine (3), together with demethoxyguadiscine (2), liriodenine (4), corypalmine (5), and coreximine (6). Their structures were elucidated on the basis of spectroscopic methods (UV, IR, EIMS, HRESIMS, 1D/2D NMR). The absolute configurations of 1 and 3 were determined from the circular dichroism curves. The presence of 7,7-dimethylaporphine alkaloids in this species is important for the chemotaxonomy of Guatteriopsis. Antimicrobial activity of compounds 1-5 was investigated, and 4 showed activity against Rhodococcus equi, with a MIC value of 10 microg x mL(-1).

Review of semiochemicals that mediate the oviposition of mosquitoes: a possible sustainable tool for the control and monitoring of Culicidae / Revisão dos semioquímicos que mediam a oviposição em mosquitos: uma possível ferramenta sustentável para o monitoramento e controle de Culicidae

The choice for suitable places for female mosquitoes to lay eggs is a key-factor for the survival of immature stages (eggs and larvae). This knowledge stands out in importance concerning the control of disease vectors. The selection of a place for oviposition requires a set of chemical, visual, olfactory and tactile cues that interact with the female before laying eggs, helping the localization of adequate sites for oviposition. The present paper presents a bibliographic revision on the main aspects of semiochemicals in regard to mosquitoes' oviposition, aiding the comprehension of their mechanisms and estimation of their potential as a tool for the monitoring and control of the Culicidae.

A seleção de locais adequados pelas fêmeas de mosquitos para depositarem seus ovos é um fator chave para a sobrevivência de seus imaturos (ovos e larvas). O conhecimento das relações ecológicas implicadas neste processo é de grande importância quando se refere a vetores de agentes patogênicos. A determinação do local de oviposição pelas fêmeas grávidas envolve uma rede de mensagens químicas, visuais, olfativas e táteis que facilitam a localização de lugares adequados para depositarem seus ovos. Neste trabalho é apresentada uma revisão bibliográfica dos principais aspectos relacionados com semioquímicos presentes na oviposição dos mosquitos auxiliando no entendimento dos mecanismos de atuação dos mesmos e potencializando a aplicação destes semioquímicos como uma possível ferramenta de monitoramento e controle de Culicidae.

Chemical composition and antimicrobial activity of the essential oils of the Amazon Guatteriopsis species.

The essential oils of Guatteriopsis blepharophylla, Guatteriopsis friesiana and Guatteriopsis hispida were obtained by hydrodistillation and analysed by GC and GC/MS. The main compound found in the leaf oil of G. blepharophylla was caryophyllene oxide (1) (69.25%). The leaf oil of G. friesiana contained predominantly beta-eudesmol (2) (51.60%), gamma-eudesmol (3) (23.70%), and alpha-eudesmol (4) (14.56%). The major constituents identified in the leaf of G. hispida were beta-pinene (38.18%), alpha-pinene (30.77%) and (E)-caryophyllene (20.59%). The antimicrobial activity of the essential oils was evaluated against 11 species of microorganisms. The oil of G. friesiana exhibited significant antimicrobial activity for all microorganisms tested, whereas that of G. hispida and G. blepharophyla had potent activity against Rhodococcus equi with MIC of 50 microg mL(-1). The major constituents of each oil were also tested separately, and showed lower activity compared to the oils. Moreover, mixtures of the main constituents, in the same proportions found in G. friesiana and G. hispida oils, did not show the same activity as the original oils.

Structure confirmation of a bioactive lactone isolated from Otoba parvifolia through the synthesis of a model compound.

Synthesis of a model compound 4 structurally related to a bioactive lactone 3 isolated from Otoba parvifolia has been accomplished. The good match between the NMR data of both compounds suggests they have identical bicyclic [3.3.1] carbon skeletons.

Efficient method to locate double bond positions in conjugated trienes.

The double bond positions of 11 conjugated trienes were unambiguously located through a simple derivatization method amenable to nanogram-scale analyses. The trienes were reacted with the powerful dienophile 4-methyl-1,2,4-triazoline-3,5-dione (MTAD), and the mass spectra of the resulting cycloadducts exhibited large diagnostic fragments which allowed the unequivocal location of the double bonds in the parent triene in most cases. Catalytic hydrogenation of the cycloadducts produced saturated compounds with characteristic mass spectral fragments from which the positions of the trienes in the parent compounds could be readily confirmed. Application of the method was demonstrated by the microscale identification of two conjugated triene and one conjugated diene components from extracts of the sex pheromone gland of the saturniid moth Automeris cecrops pamina.

Males Are Attracted by Female Traps: A New Perspective for Management of Diabrotica speciosa (Germar) (Coleoptera: Chrysomelidae) Using Sexual Pheromone / Machos são Atraídos por Armadilhas com Fêmeas: Uma Nova Perspectiva para Manejo de Diabrotica speciosa (Germar) (Coleoptera: Chrysomelidae) Usando Feromônio Sexual

As respostas de Diabrotica speciosa (Germar) para armadilhas com adultos foram estudadas como sugestão da produção de feromônio. Inicialmente, um ensaio para estabelecer a altura adequada para colocação de armadilhas para capturar D. speciosa foi conduzido em campo de feijão. Armadilhas colocadas a 0,25 m de altura capturaram cerca de 3,5 vezes mais adultos do que a 0,5; 0,75 e 1,0 m. As respostas para fêmeas e machos virgens de duas idades (mais novos = 24 a 72h e mais velhos = 72 a 120h após emergência de adultos), fêmeas e machos copulados foram avaliadas em campo de feijão consorciado com café, Coffea arabica L. Armadilhas com fêmeas virgens capturaram cerca de 22 (mais jovens) e 13 vezes (mais velhas) mais adultos machos do que as testemunhas (armadilhas sem insetos). Capturas foram cerca de 70 por cento mais efetivas usando fêmeas mais jovens. Nenhum dos outros tratamentos aumentou as capturas nas armadilhas. Os resultados indicam que há um feromônio sexual produzido por fêmeas em D. speciosa.

The field responses of Diabrotica speciosa (Germar) to traps baited with adults were studied as an suggestion of the pheromone production. Firstly, an assay to settle a suitable height placement to capture D. speciosa was carried out in common beans, Phaseolus vulgaris L., field. Traps placed at 0.25-m height captured ca. 3.5 times more beetles than 0.5, 0.75 and 1.0-m traps. The responses to virgin females and males of two ages (younger = 24 to 72h and older = 72 to 120h after adult emergence), mated females and males were assessed in common bean interplanted among coffee, Coffea arabica L., field. Virgin females baited traps captured ca. 22 times (younger) and 13 times (older females) more male beetles than control traps. Captures were ca. 70 percent more effective using younger females. None of the other treatments improved trap attraction. These results strongly indicated that there is a female-produced sexual pheromone in D. speciosa.