The aim of the current study was the valorization of hesperidin, the dominant flavonoid in citrus processing waste, by microwave-assisted synthesis of hesperidin-Mg complex, improving its antioxidant activity and insecticidal potential. Here we show, for the first time, that microwave-assisted synthesis of [Mg(hesp)2(phen)]OAc (1) (hesp: hesperidin, phen: phenanthroline) improve the reaction rate and yield. The nuclear magnetic resonance (NMR) experiments proved to be powerful tools for the identification of three isomers in metal complexes. Moreover, we explore the insecticidal potential of 1 and [Mg(phen)2(Isov)]OAc (2) (Isov : isovanillic acid) complexes against three insects. Complex 1 killed 80% of adults whitefly at 0.14 μmol L-1, and 2 76% at 0.36 μmol L-1. There was a total mortality of Spodoptera frugiperda with 2 at 0.39 μmol L-1, and 83% with 1 at 0.14 μmol L-1. Both have similar activity, and represent a novel group of insecticide for Bemisia tabaci and S. frugiperda; nevertheless, the benefits of both as Myzus persicae repellent require further evaluation.

Croton grewioides Baill. popularly known as “canelinha” or “canelinha-de-cheiro” has been used for the treatment of influenza, antitussive, febrifuge and headache; however, the study of its phytochemical composition is limited. The aim of this study was to investigate the effect of the extraction method and seasonality through leaf extracts of four accessions of Croton grewioides by fingerprint chromatograms aided by principal component analysis to analyze the differences and similarities among the samples. We aimed also to provide chemical characterization of isolated secondary metabolites using semi-preparative liquid chromatography. The results showed that only the chemical profile of the methanolic extracts of accessions 101 and 113 were influenced by the seasonality. For the first time, four flavonoids were isolated through semi-preparative chromatography in this species, characterized as quercetin 3-O-β-D-galactopyranosyl-(1→2)-α-L-rhamnopyranoside-(1→6)-α-L-rhamnopyranoside (1), quercetin 3-O-β-D-galactopyranosyl-(1→2)-α-apiopyranoside-(1→6)-α-L-rhamnopyranoside (2), quercetin 3-O-glucopyranoside (3) and 3-O-methyl-quercetin (4), the flavonoid (2) has been recognized as a new triglycosylated derivative.

ABSTRACT Chemical investigation of the aqueous fraction of the ethanol extract from the Brazilian endemic marine sponge Clathria (Clathria) nicoleae Vieira de Barros, Santos & Pinheiro, 2013, Microcionidae, sampled from a 55 m deep rhodolith bed at the Amazon River mouth, led to the isolation of a new hexapeptide, clathriamide (1). HP-20 resin was used to capture compound 1 from the aqueous fraction, which was purified by additional chromatographic steps. The absolute configuration of the amino acids of 1 was determined by advanced Marfey's analysis using 5-fluoro-2,4-dinitrophenyl-Nα-L-tryptophanamide. The amino acid derivatives analyzed by ultra-performance liquid chromatography coupled to a mass spectrometry using a C8 column enabled a good chromatographic resolution of L-Ile and L-allo-Ile, previously unfeasible using C18 column.

ABSTRACT Anthracnose is a crop disease usually caused by fungi in the genus Colletotrichum or Gloeosporium. These are considered one of the main pathogens, causing significant economic losses, such as in peppers and guarana. The current forms of control include the use of resistant cultivars, sanitary pruning and fungicides. However, even with the use of some methods of controlling these cultures, the crops are not free of anthracnose. Additionally, excessive application of fungicides increases the resistance of pathogens to agrochemicals and cause harm to human health and the environment. In order to find natural antifungal agents against guarana anthracnose, endophytic fungi were isolated from Amazon guarana. The compounds piliformic acid and cytochalasin D were isolated by chromatographic techniques from two Xylaria spp., guided by assays with Colletotrichum gloeosporioides. The isolated compounds were identified by spectrometric techniques, as NMR and mass spectrometry. This is the first report that piliformic acid and cytochalasin D have antifungal activity against C. gloeosporioides with MIC 2.92 and 2.46 µmol mL-1 respectively. Captan and difenoconazole were included as positive controls (MIC 16.63 and 0.02 µmol mL-1, respectively). Thus, Xylaria species presented a biotechnological potential and production of different active compounds which might be promising against anthracnose disease.

The purification of the hexanic extract from the leaves of a native variety of mahogany collected in Santarém (Pará, Brazil) afforded eight new phragmalin limonoids along with eight known compounds. This variety, according to field observations, should be considered resistant against the specialist insect Hypsipyla grandella, that attacks the terminal shoots only of juvenile mahogany and not of matured ones. After observing that four phragmalin limonoids were present just in mature leaves, we carried out two bioassays, one of them using a fraction from hexanic extract of mature leaves and another using a mix of four limonoids. The results of the bioassay using the isolated limonoids showed a direct effect on the larvae of H. grandella, suggesting that these limonoids act as inhibitors of larvae growth. This should be the reason why larvae choose the young leaves for their development.

The present investigation tests the effects against feeding by fishes of crude extracts obtained from eleven distinct populations of the bryozoan Amathia verticillata, an invasive species found globally in tropical to warm-temperate waters. Investigation of extracts from 11 populations of A. verticillata led to the identification and quantification of the known indole alkaloid 2,5,6-tribromo-N-methylgramine and isolation and identification of the new indole alkaloid, 2,6-dibromo-N-methylgramine. One extract of A. verticillata from Brazil significantly deterred feeding, while other extracts of A. verticillata from Florida significantly stimulated feeding by fishes, in field assays performed in Brazil. The same extracts of Florida samples showed variable effects on feeding, ranging from attraction to deterrence, in assays carried out in Florida. The absence of broad chemical defenses against feeding by fish suggests that the establishment of A. verticillata as an invasive species into new areas may be due to reasons other than defensive chemistry.

The industrial development, urbanization and agriculture play a major role in the degradation of the global environmental. Thus, the wastewater treatments need to be monitored continuously to ensure efficient operation. This manuscript presents an application of 1H nuclear magnetic resonance (NMR) associated with chemometric and quantitative analyses to study the wastewater before and after the sewage treatment plant (STP). The concentration of compounds related to organic matter degradation ranged with treatment and seasonality. Anomalous discharges and the influence of stormwater on the sewage composition were further identified. All the variations indicated that the employed procedure might be useful to enhance the effectiveness of STPs, plan prevention actions for equipment protection and preserve the environment.

O presente estudo foi realizado com dois espécimes do molusco nudipleura Pleurobranchus areolatus que demonstraram acumular derivados oxidados da rodriguesina A. O ácido rodriguêsico apresenta um grupo ácido carboxílico no lugar do grupo metila de uma cadeia alquila terminal da rodriguesina A. Um grupo hidroxamato foi observado na porção dicetopiperazínica do ácido rodriguêsico. As estruturas do ácido rodriguêsico e do hidroxamato do ácido rodriguêsico foram estabelecidas por análise de seus dados espectroscópicos, inclusive sua configuração absoluta. Dois ésteres metílicos dos ácidos rodriguêsicos foram isolados como compostos majoritários, porém considerados como artefatos de isolamento.

In the present investigation, two specimens of the nudipleuran mollusc Pleurobranchus areolatus have shown to accumulate oxidized rodriguesin A derivatives. Rodriguesic acid presents a carboxylic acid replacing the terminal methyl group of the alkyl chain of rodriguesin A. A hydroxamate group was also present on the diketopiperazine moiety of a rodriguesic acid derivative. The structures of both rodriguesic acid and of rodriguesic acid hydroxamate have been established by analysis of spectroscopic data, including their absolute configuration. Two methyl esters of the rodriguesic acids have been isolated as major compounds, but were considered to be isolation artifacts.

As reações químicas realizadas por microorganismos têm sido utilizadas como uma ferramenta na química moderna. Este artigo relata a produção de ácido micofenólico e uma nova ftalida pelo fungo endofítico Penicillium crustosum obtido a partir de grãos de café. O fungo foi cultivado em meio líquido durante um período de sete dias, e depois disso, o meio de cultura foi dividido em quatro lotes: A, B, C e D, nos quais diferentes substâncias orgânicas foram adicionadas. O lote A foi mantido como controle para avaliar a ocorrência de biotransformação. Os ácidos orgânicos foram adicionados ao meio de cultura dos lotes B (ácidos ferúlico e quínico) e C [ácido cinâmico e 3,4-(metilenodioxi) cinâmico], e cafeína foi adicionada ao lote D. Todos estes compostos orgânicos foram dissolvidos em DMSO, e a fermentação foi mantida por mais 13 dias, totalizando 20 dias. O ácido micofenólico foi isolado a partir da cultura sem adição de ácidos (lote A). O ácido micofenólico e uma nova ftalida, 5-hidroxi-7-metoxi-4-metilftalida, foram isolados a partir dos lotes B e C, e ácido micofenólico e cafeína (adicionada ao meio de cultura) foram isolados a partir do lote D. As estruturas foram determinadas pela técnica de RMN e confirmadas pelas técnicas de MS e MS/MS.

The chemical reactions carried out by microorganisms have been used as a tool in modern chemistry. This paper reports the production of mycophenolic acid and a new phthalide by the endophytic fungus Penicillium crustosum obtained from coffee seeds. The fungus was cultivated in a liquid medium for a period of seven days and after that the culture medium was divided into four treatments: A, B, C and D, to which different organic substances were added. Treatment A was maintained as the control to evaluate the occurrence of biotransformation. Organic acids were added to the culture media of treatments B (ferulic and quinic acids) and C [cinnamic and 3,4-(methylenedioxy) cinnamic acids], and caffeine was added in the treatment D. All these organic compounds were dissolved in DMSO, and the fermentation was maintained for more 13 days, totalizing 20 days. Mycophenolic acid was isolated from the culture with no added acids (treatment A). Mycophenolic acid and a new phthalide, 5-hydroxy-7-methoxy-4-methylphthalide were isolated from treatments B and C, and mycophenolic acid and caffeine (added to the culture medium) were isolated from treatment D. The structures were determined by NMR techniques and confirmed by MS and MS/MS techniques.

Ultrafast 2D NMR is a powerful methodology that allows recording of a 2D NMR spectrum in a fraction of second. However, due to the numerous non-conventional parameters involved in this methodology its implementation is no trivial task. Here, an optimized experimental protocol is carefully described to ensure efficient implementation of ultrafast NMR. The ultrafast spectra resulting from this implementation are presented based on the example of two widely used 2D NMR experiments, COSY and HSQC, obtained in 0.2 s and 41 s, respectively.

Experimentos de incorporação com precursores marcados com 13C foram realizados objetivando-se estabelecer a biossíntese de dois dihidropirróis N-acilados, (8E)-1-(2,3-dihidro1H-pirrol-1-il)-2-metildec-8-eno-1,3-diona (1) e 1-(2,3-dihidro-1H-pirrol-1-il)-2-metildecano1,3-diona (2), isolados de culturas de Penicillium citrinum de origem marinha. A biossíntese de ambos, 1 e 2, procede através da incorporação de acetato, metionina e ornitina.

Feeding experiments with 13C-labeled precursors were performed in order to establish the biosynthesis of two N-acylated dihydropyrroles, (8E)-1-(2,3-dihydro-1H-pyrrol-1-yl)-2-methyldec8-ene-1,3-dione (1) and 1-(2,3-dihydro-1H-pyrrol-1-yl)-2-methyldecane-1,3-dione (2), isolated from the cultures of a marine-derived Penicillium citrinum. The biosynthesis of both, 1 and 2, involves the incorporation of acetate, methionine and ornithine.

O gênero Leuconostoc pertence a um grupo de bactérias lácticas normalmente isoladas de vegetais fermentados, que inclui espécies envolvidas na produção de exopolissacarídeos (EPS). Esses biopolímeros possuem potencial comercial considerável. Devido à grande variedade de aplicações industriais, de EPS, o presente estudo teve como objetivo produzir e caracterizar o nativo exopolissacarídeo cepa Leuconostoc pseudomesenteroides R2, que foi isolado de repolho coletado em uma região semi-árida da Bahia. Utilizamos as seguintes condições para a produção de EPS: 10,7% de sacarose, pH 8,2, sem agitação e incubação a 28º C por 30 horas. O caldo fermentado foi tratado com etanol, gerando dois tipos de substâncias de polissacarídeos (EPS I e EPS II). A identificação do EPS I e EPS II foi realizada através das técnicas espectroscópicas de FT-IR e RMN de ¹H, 13C e DEPT 135. As duas substâncias foram identificadas como dextrano polissacarídeos lineares (1 → 6), indicando características diferentes no que diz respeito à análise térmica e densidade de empacotamento sem viscosidade e tempo de solubilização. Ambas as dextranas são de baixa densidade, possuem alta estabilidade térmica e apresentaram comportamento característico de polímeros pseudoplásticos.

The genus Leuconostoc belongs to a group of lactic acid bacteria usually isolated from fermented vegetables, which includes species involved in the production of exopolysaccharides (EPS). These biopolymers possess considerable commercial potential. Because of the wide variety of industrial applications of EPS, this study aimed to produce and characterize the native exopolysaccharide strain Leuconostoc pseudomesenteroides R2, which was isolated from cabbage collected in a semi-arid region of Bahia. We employed the following conditions for the production of EPS: 10.7% sucrose, pH 8.2, without agitation and incubation at 28ºC for 30 hours. The fermentation broth was treated with ethanol and generated two types of polysaccharide substances (EPS I and EPS II). The identification of EPS I and EPS II was conducted using FT-IR, ¹H, 13C and DEPT-135 NMR spectra. The two substances were identified as linear dextran α polysaccharides (1 → 6) which indicated different characteristics with respect to thermal analysis and density of free packaging, viscosity and time of solubilization. Both dextrans are of low density, possess high thermal stability and exhibited the behavior characteristic of pseudoplastic polymers.

The chemical investigation of the MeOH extract from the bryozoan B. dentata MeOH yielded tambjamines A (1), C (3), D (4), K (6), aldehyde 8 and the new tambjamine J1(9), while the extract of its predator, the nudibranch Tambja stegosauriformis, yielded tambjamines C and K, along with aldehyde 8. Furodisinin lactone (11) was isolated from the nudibranch Hypselodoris lajensis, a compound previously isolated from Dysidea sponges. The alkaloid 2,5,6-tribromo-N-methylgramine (12) was isolated from the nudibranch Okenia zoobotryon and from its prey, the bryozoan Zoobotryon verticillatum, the only source of 12 previously known.

The importance of medicinal plants and their use in industrial applications is increasing worldwide, especially in Brazil. Phyllanthus species, popularly known as "quebra-pedras" in Brazil, are used in folk medicine for treating urinary infections and renal calculus. This paper reports an authenticity study, based on herbal drugs from Phyllanthus species, involving commercial and authentic samples using spectroscopic techniques: FT-IR, ¹H HR-MAS NMR and ¹H NMR in solution, combined with chemometric analysis. The spectroscopic techniques evaluated, coupled with chemometric methods, have great potential in the investigation of complex matrices. Furthermore, several metabolites were identified by the NMR techniques.

Nanocompósitos a base de poli(etileno-co-acetato de vinila) (EVA) e óxido de sílica (SiO2), com tamanho nanométrico da ordem de 40 nm, foram preparados via intercalação por solução, empregando clorofórmio como solvente. Os nanocompósitos foram caracterizados principalmente pela espectroscopia de ressonância magnética nuclear (RMN), empregando a análise dos núcleos de carbono-13 (matriz polimérica); silício-29 (nanopartícula) e pela determinação do tempo de relaxação spin-rede do núcleo de hidrogênio no eixo rotatório (T1rH) (matriz polimérica). Pelos dados de RMN foi observado que até cerca de 5% de sílica em massa obteve-se um nanocompósito polimérico com boa dispersão da sílica devido a uma forte interação entre a sílica e matriz de EVA.

Nanocomposites of poly(ethylene-co-vinyl acetate)/silica (SiO2) with dimensions of ca. 40 nm were prepared via solution intercalation employing chloroform as a solvent. They were mainly characterized with nuclear magnetic resonance spectroscopy (NMR) employing carbon-13 (polymeric matrix), silicon-29 (nanoparticles) and through the determination of the proton spin-lattice relaxation time in the rotating frame (T1rH) (polymer matrix). From the NMR results it was inferred that up to 5% of silica in mass a well dispersed nanocomposite was obtained, owing to a strong interaction between silica and the EVA matrix.