Abstract There is an increasing interest in essential oils extracted from Verbenaceae plant species as potential sources of biologically active compounds that could provide a starting point for designing novel phyto-pharmaceuticals in aquaculture. The present study was aimed to investigate the chemical composition, antioxidant activity, acute toxicity and antimicrobial effects against Vibrio parahaemolyticus of essential oils extracted from Lippia alba and L. origanoides. Approximately 23 components were identified and quantified by gas chromatography-mass spectrometry and flame ionization detection in each species’ essential oil. The most predominant compounds were geranial (23.0%), limonene (17.0%) and neral (15.5%) in L. alba, and thymol (47.2%), p-cymene (16.0%) and E-caryophyllene (11.3%) in L. origanoides. The essential oils have antibacterial activity against Vibrio parahaemolyticus presenting Minimum Inhibitory Concentration (MIC) and Bactericidal Concentration (MBC) values between 156-625 µg mL-1. The essential oils also show antioxidant potential estimated by 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging assays, presenting IC50 of 60.16 mg mL-1 and 0.22 mg mL-1 for L. alba and L. origanoides EO, respectively. Both oils were classified as toxic to Artemia salina nauplii. Therefore, these essential oils may be useful for controlling pathogenic bacteria important to the aquaculture industry.

Black mold, a disease caused by the fungus Pilgeriella anacardii Arx & Müller, affects cashews (Anacardium occidentale). Some cashew clones are more resistant to the pathogen; however, little is known about the chemical profile responsible for this trait. The investigation of volatile organic compounds (VOCs) from leaves of dwarf cashew clones resistant (BRS 226 and BRS 265) and susceptible (CCP 76 and BRS 189) to the pathogen was carried out. Leaves were collected during the months of disease incidence and decline (March to July 2019, Brazil), and VOCs were analyzed by gas chromatography-mass spectrometry (GC-MS) combined with chemometric tools. The GC-MS analysis tentatively identified 96 compounds. Partial least squares discriminant analysis (PLS-DA), orthogonal partial least squares discriminant analysis (OPLS DA), hierarchical cluster analysis (HCA), and ROC curves analysis were useful in dividing VOCs into distinct resistance and associated chemical susceptibility groups for different clones. The VOCs in the leaves of the resistant clones were identified as alcohols and aldehydes containing six carbons: (E)-hex-2-enal, hex-3-en-1-ol, (Z)-hex-2-en-1-ol, (E)-hex-2-en-1-ol, and hexan-1-ol. Moreover, α-pinene, pseudolimonene, α-phellandrene, β-myrcene, sylvestrene, β-cis-ocimene, methyl salicylate, myrtenol, α-copaene, γ-muurolene, germacrene D, valencene, and germacrene B were also detected in these samples and may be candidate chemical biomarkers for cashew resistance to P. anacardii.

Metabolomics, together with analytical methods and chemometric tools, point to new paths for selecting species that are resistant to pests and diseases. In this work, the forage palm species' metabolomic profile was investigated, and the relation between the chemical composition and resistance to Dactylopius opuntiae (carmine cochineal). The study was performed in cladodes of different non-susceptible cultivars (Nopalea cochenillifera (L.) Salm-Dyck, Opuntia stricta (Haw.), Nopalea cochenillifera and susceptible cultivar (Opuntia ficus-indica (L.) Mill.)). Metabolic profile showed 28 metabolites detected in the four species. From these total, 18 metabolites were annotated using UPLC-QTOF-MSE (ultra-performance liquid chromatography coupled with an electrospray ionization quadrupole time-of-flight mass spectrometry operating in MSE mode). By comparing the chemical profiles of non-susceptible and susceptible species through the application of chemometric tools, it was possible to obtain biomarkers (quercetin-3-O-2',6'-dirhamnosylglucoside, quercetin rhamnosyl dihexoside, and isorhamnetin-3-sophoroside-7-rhamnoside) that may be associated with resistance to carmine cochineal. Metabolomics based on UPLC-QTOF-MSE and chemometric allowed to establish the biomarkers knowledge of the resistance present in forage palm species. These results contribute to developing the initial understanding of flavonoids' role in the defense mechanisms of cactaceans and can be useful for application in breeding programs; it can increase the chances of success in creating new varieties of plants not susceptible to carmine cochineal.

Our study aimed at the development of a method based on ultra-performance liquid chromatography coupled to mass spectrometry (UPLC-ESI-MS) using selected ion monitoring for the simultaneous quantitation of the alkaloids galantamine, pseudolycorine, sanguinine and narciclasine in Amaryllidaceae species (Hippeastrum elegans, Habranthus cf. irwinianus, Hymenocallis littoralis and Griffinia nocturna). The alkaloids were extracted from dried and ground bulbs (100 mg) using liquid-liquid microextraction followed by solid phase extraction in cation exchange cartridges. The quantification method showed good linearity (correlation coefficient, R ≥ 0.9968) and selectivity for a run time of 10 min. All values were within the acceptable limits for recovery (87.5-96.2%), interday (coefficient of variation, CV%, 1.3-8.4%) and intraday precision (CV% 5.7-8.1%), except narciclasine (70%). The limits of detection and quantification were 5-100 and 20-350 ng mL-1, respectively. Our method demonstrated to be rapid, sensitive and reliable, therefore appropriate for being employed in the prospection of new source of galantamine and other alkaloids.

A method based on QuEChERS (quick, easy, cheap, effective, rugged, and safe) extraction and gas chromatography-mass spectrometry (GC-MS) detection was described for the pesticides dichlorvos, disulfoton, ethoprophos, parathion methyl, fenchlorphos, chlorpyrifos, azinphos methyl and prothiofos in sapodilla. For all compounds studies, it was observed a strong matrix effect showing the need to use matrix matched calibration strategy. Method was validated, and good linearity (R > 0.99) was obtained for all pesticides studied with limits of detection (LODs) and quantification (LOQs) ranging from 0.01 to 0.06 mg kg-1 and 0.03 to 0.2 mg kg-1, respectively. Recovery studies were performed at different levels (0.08, 0.10, 0.14, 0.20, 0.35 and 1.17 mg kg-1) and showed good results (between 70 and 120% with relative standard deviation (RSD) < 20%). A statistical test was applied to the coefficients of the analytical curves obtained in the sapodilla matrix. Analyses of commercial samples showed chlorpyrifos were detected in about 70 and 33% for fruit and pulps samples, respectively. It should be noted that chlorpyrifos is not permitted in sapodilla crops by ANVISA and EC guidelines.

As mudanças morfológicas e atividade enzimática em cultura de células de Citrus aurantium em suspensão foram acompanhadas após eliciação com quitina. Os oligômeros de quitina apresentaram um rápido efeito, com uma atividade máxima após 3 h, seguida de um decréscimo gradual aos níveis originais com 8 h de incubação. As paredes celulares apresentaram processo de lignificação e as proteínas citoplasmáticas tornaram-se menos reativas aos corantes aniônicos. Nos materiais tratados observou-se uma redução no tamanho dos grãos de amido, um aumento no número de vacuólos autofágicos, deposição de secreção no espaço pericelular e desfibrilação dos polímeros da parede celular. Os oligômeros de quitina induziram a atividade da peroxidase e da L-fenilalanina amônia-liase. A atividade das peroxidases extracelulares aumentou de 0.20 U mL-1 após 1 h para 0.45 U mL-1 em 3 h, seguida de um decréscimo gradual até 8 h. O padrão de isoenzimas revelou uma predominância de isoenzimas básicas.

Morphological changes and enzyme activity in suspension-cultured cells of Citrus aurantium were followed after chitin elicitation. Chitin oligomers presented a rapid effect with a maximum activity after 3 h followed by a gradual decrease to the original levels at 8 h of incubation. Cell walls presented a lignification process and the cytoplasmatic protein became less reactive to anionic stains. In the treated material a reduction in starch grain size, an increase in the number of autophagic vacuoles, deposition of secretion in the pericellular space and a defibrillation of the cell-wall polymers were observed. Chitin oligomers increased peroxidase and L-phenylalanine ammonia-lyase activities. Extracellular peroxidase activity increased from 0.20 U mL-1 after 1 h to 0.45 U mL-1 at 3 h followed by a gradual decrease up to 8 h. The peroxidase isoenzyme pattern revealed a predominance of basic isoenzymes in these cells.

Um procedimento de Microextração em Fase Sólida em Headspace (HS-SPME) para isolamento e determinação de alquilpirazinas em liquor de cacau, usando Cromatografia Gasosa com Detecção por Ionização em Chama (GC-FID) é apresentado aqui. As condições operacionais de HS-SPME foram otimizadas usando extrações de amostras fortificadas com quantidades conhecidas de alquilpirazinas tipicamente encontradas em derivados de cacau. A eficiência máxima de extração foi obtida com fibras de SPME recobertas com 65 µm de Carbowax/divinilbenzeno. Em adição, os melhores resultados foram obtidos usando 60 ºC como temperatura de extração, 15 min como tempo de equilíbrio amostra/headspace e 45 min como tempo de extração. Observou-se também que o uso de solução aquosa saturada de NaCl para suspender as amostras durante as extrações resultou em um incremento significativo nas áreas dos picos. Este procedimento se mostrou efetivo para a determinação das razões pirazínicas (quocientes entre as áreas dos picos de alquilpirazinas), que são úteis como parâmetros de qualidade para liquor de cacau.

A Headspace Solid Phase Microextraction (HS-SPME) procedure for isolation and determination of alkylpyrazines in cocoa liquor, using Gas Chromatography with Flame Ionization Detection (GC-FID) for the separation and detection of the analytes, is presented here. The HS-SPME operational conditions were optimized using extractions of samples spiked with known amounts of alkylpyrazines typically found on cocoa products. The maximum extraction efficiency was obtained using SPME fibers coated with 65 µm Carbowax/divinylbenzene. Additionally, the best results were achieved with extraction temperature of 60 ºC, 15 min of sample/headspace equilibration time and 45 min extraction time. It was also observed that suspending the samples in saturated aqueous NaCl solution during extractions resulted in a significant increment on the peak areas. This procedure was found to be effective to determine the so-called pyrazinic ratios (quotient between peak areas of alkylpyrazines), which are useful as quality parameters for cocoa liquor.