Antifungal activity and inhibition of aflatoxins production by Zingiber officinale Roscoe essential oil against Aspergillus flavus in stored maize grains / Atividade antifúngica e inibição da produção de aflatoxinas pelo óleo essencial de Zingiber officinale Roscoe contra Aspergillus flavus em grãos de milho armazenados

ABSTRACT: Essential oils are possible alternatives to the use of synthetic pesticides for control of fungal contamination. Ginger (Zingiber officinale) essential oil (GEO) is known for having antifungal and antiaflatoxigenic properties, but its use as a fumigant in situ has not been studied yet. The aim of this study was to evaluate GEO's effects upon Aspergillus flavus as a fumigant agent in stored maize grains. The main compounds reported in GEO were α-zingiberene (23.85%) and geranial (14.16%), characterized by gas chromatography-mass spectrometry and nuclear magnetic resonance. The GEO was used as a fumigant in irradiated maize grains in concentrations ranging from 5 to 50 µg/g and the resulting effects were compared to a synthetic antifungal agent (carbendazim and thiram), an antifungal traditionally used for seed treatment. The antifungal efficacy of GEO against A. flavus has been proven in a dose-dependent manner through in situ (maize grains) test. The GEO inhibited aflatoxin production at concentrations 25 and 50 µg/g and controlled fungal growth. Therefore, GEO can be used as an effective and non-toxic alternative to conventional treatments in stored maize grains for the natural control of A. flavus.

RESUMO: Os óleos essenciais são possíveis alternativas ao uso de praguicidas sintéticos no controle da contaminação por fungos. O óleo essencial de gengibre (Zingiber officinale - OEG) é conhecido por possuir propriedades antifúngicas e antiaflatoxigênicas, mas seu uso como fumigante in situ ainda não foi estudado. O objetivo deste estudo foi avaliar os efeitos do OEG sobre Aspergillus flavus como agente fumigante em grãos de milho armazenados. Os principais compostos encontrados no OEG foram α-zingibereno (23,85%) e geranial (14,16%), caracterizados por cromatografia gasosa acoplada a espectrometria de massas e ressonância magnética nuclear. O OEG foi utilizado como fumigante em grãos de milho irradiados em concentrações variando de 5 a 50 µg/g e os efeitos resultantes foram comparados a um agente antifúngico sintético (carbendazim e tiram), antifúngico tradicionalmente usado para o tratamento de sementes. A eficácia antifúngica do OEG contra A. flavus foi comprovada de maneira dependente da dose através do teste in situ (grãos de milho). O OEG inibiu a produção de aflatoxina nas concentrações 25 e 50 µg/g e controlou o crescimento de fungos. Portanto, o OEG pode ser usado como uma alternativa eficaz e não tóxica aos tratamentos convencionais em grãos de milho armazenados para o controle natural de A. flavus.

Aflatoxin B1 and zearalenone in soybeans: occurrence and distribution in whole and defective kernels.

Few studies have addressed the distribution of mycotoxins in soybean and/or their processing fractions. In this study, samples from commercial lots were collected in four Brazilian states. The distribution of mycotoxins in soybean fractions, according to their commercial grading system, namely whole kernels (WK), split, broken and crushed kernels (SBCK), damaged kernels (DK), heat damaged and burned kernels (HDBK), moldy kernels (MK), greenish kernels (GK), foreign material + impurities (FMI), were analyzed using HPLC-FLD. AFB1 and ZEN tested positive in 43.3 and 80%, respectively. The incidence of AFB1 was higher in MK (50%), followed by HDBK (30.4%) and FMI (26.0%). ZEA incidence ranged from 69% (SBCK) to 100% (HDBK). Co-occurrence (53.3%) in at least one fraction was also detected. Brazil is the second world producer of soybeans, which places the country in a very important position. Therefore, the information provided is crucial and timely relevant for the industry and policymakers.

Searching for promising sources of grain protectors in extracts from neotropical annonaceae / Búsqueda de fuentes prometedoras de protectores de granos en extractos de anonaceas neotropicales

To investigate potential sources of novel grain protector compounds against Sitophilus zeamais (Coleoptera: Curculionidae), which is an important insect pest of stored cereals, this study evaluated the bioactivity of ethanolic extracts (66) prepared from 29 species belonging to 11 different genera of Neotropical Annonaceae. A screening assay demonstrated that the most pronounced bioactive effects on S. zeamais were caused by ethanolic extracts from Annona montana, A. mucosa, A. muricata, and A. sylvatica seeds, causing the death of all weevils exposed, almost complete inhibition of the F1 progeny and a drastic reduction in grain losses. Furthermore, the ethanolic extracts obtained from the leaves of A. montana, A. mucosa, A. muricata, and Duguetia lanceolata, especially A. montana and A. mucosa, demonstrated significant bioactive effects on the studied variables; however, the activity levels were less pronounced than in the seed extracts, and the response was dependent on the concentration used. This study is the first to report the activity of secondary metabolites from D. lanceolata on insects as well as the action of A. sylvatica on pests associated with stored grains.

Para investigar las posibles fuentes de nuevos compuestos protectores de granos contra Sitophilus zeamais (Coleoptera: Curculionidae), una importante plaga de los cereales almacenados, este estudio evaluó la bioactividad de los extractos etanólicos (66) preparados a partir de 29 especies pertenecientes a 11 géneros distintos de Anonaceas Neotropicales. Un ensayo de selección demostró que los efectos bioactivos más relevantes sobre S. zeamais fueron causados por los extractos etanólicos de las semillas de Annona montana, de A. mucosa, de A. muricata y de A. sylvatica, que causaron la muerte de todos los gorgojos expuestos, la inhibición parcial de la progenie F1 y una drástica reducción de las pérdidas de grano. Además, los extractos etanólicos obtenidos de las hojas de A. montana, de A. mucosa, de A. muricata y de Duguetia lanceolata, especialmente de A. montana y de A. mucosa, demostraron efectos bioactivos significativos sobre las variables estudiadas. Sin embargo, los niveles de bioactividad fueron menores en comparación con los extractos de semillas, y la respuesta fue dependiente de la concentración utilizada. Este estudio es el primer relato sobre la actividad de los metabolitos secundarios de D. lanceolata sobre insectos, así como la acción de A. sylvatica sobre plagas asociadas a los granos almacenados.

Co-occurrence and distribution of deoxynivalenol, nivalenol and zearalenone in wheat from Brazil.

Fusarium mycotoxins deoxynivalenol (DON), nivalenol (NIV) and zearalenone (ZEN) were investigated in wheat from the 2009 and 2010 crop years. Samples (n = 745) from commercial fields were collected in four wheat producing regions (WPR) which differed in weather conditions. Analyses were performed using HPLC-DAD. Contamination with ZEN, DON and NIV occurred in 56, 86 and 50%, respectively. Also, mean concentrations were different: DON = 1046 µg kg(-1), NIV < 100 µg kg(-1) and ZEN = 82 µg kg(-1). Co-occurrence of ZEN, DON and NIV was observed in 74% of the samples from 2009 and in 12% from 2010. Wet/cold region WPR I had the highest mycotoxin concentration. Wet/moderately hot region WPR II had the lowest mycotoxin levels. Furthermore, the mean concentration of each mycotoxin was higher in samples from 2009 as compared with those from 2010. Precipitation during flowering or harvest periods may explain these results.

Efeito do tratamento com óleos essenciais sobre a qualidade fisiológica e sanitária das sementes de milho (Zea mays) / Effect of essential oils on the physiological and sanitary quality of maize seed (Zea mays)

O desenvolvimento de pesticidas é uma constante no setor agropecuário, visando oferecer produtos menos agressivos ao meio ambiente e novos princípios ativos, evitando o aparecimento de resistência. O estudo de alternativas aos fungicidas utilizados no tratamento de sementes tem nos óleos essenciais um campo para prospecção. Esta pesquisa teve como objetivo avaliar os efeitos dos óleos essenciais provenientes de folhas de C. citriodora e E. camaldulensis , em sementes de milho da variedade AL Bandeirante, de diferentes localidades. A qualidade fisiológica e sanitária das sementes foi avaliada quando se trataram as amostras utilizando os óleos individualmente, a mistura equitativa desses óleos e o tratamento com um antifúngico comercial. Foi observado que o tratamento com os óleos C. citriodora e E. camaldulensis e a mistura dos óleos não afetou a germinação imediata das sementes de Avaré. No lote de Bernardino de Campos, o tratamento com C. citriodora foi prejudicial; com o E. camualdulensis , apesar de não diferenciar estatisticamente dos demais, diminuiu a germinação, o que impediria sua utilização como semente, segundo o padrão normatizado (de 85%) pelo Ministério da Agricultura, Pecuária e Abastecimento (MAPA). O óleo de E. camaldulensis apresentou efeito fitotóxico, diminuindo o comprimento das plântulas; a acetona utilizada como solvente não influenciou sobre a germinação, mas apresentou efeito fitotóxico após o envelhecimento acelerado. A aplicação dos óleos isoladamente foi capaz de diminuir a incidência dos fungos dos gêneros Penicillium e Fusarium , mas para Aspergillus o comportamento foi semelhante ao antifúngico comercial, não apresentando efeito quando comparado ao tratamento testemunha.(AU)

The development of pesticides is a constant in the agricultural sector in order to offer products less aggressive to the environment and new active ingredients, preventing the emergence of resistance. The alternative study to fungicides used for seed treatment has the essential oils field for prospecting. This research aimed to evaluate the effects of essential oils from leaves of C. citriodora and E. camaldulensis in maize seed variety AL Bandeirante, from different locations. The physiological and sanitary quality of the seeds were evaluated when treated samples using the oils individually, equal mixture of these oils and treatment with a commercial antifungal. It was observed that the treatment with the oils C. citriodora , E. camaldulensis and the mixture of oils did not affect the immediate germination of seeds Avare. In the batch Bernardino de Campos, treatment with C. citriodora was harmful and E. camualdulensis , although not statistically differ from the others, decreased germination which would prevent its use as seed, according to the standard regulated by the Ministry of Agriculture, Livestock and Supply (MAPA), 85%. The E. camaldulensis oil showed phytotoxic effect decreasing the length of seedlings, acetone used as a solvent had no effect on germination but showed phytotoxic effect after accelerated aging. The application of oils alone was able to reduce the incidence of fungi of the genus Penicillium and Fusarium, Aspergillus but the behavior was similar to commercial antifungal, showing no effect when compared to the control treatment.(AU)

Distribution of aflatoxins in corn fractions visually segregated for defects

The aflatoxin distribution in corn fractions obtained after visual segregation for defects in 30 samples, known to be contaminated, was studied. Each sample was passed through a 5.0 mm round holes sieve, graded for defects and then segregated in sound kernels (regular kernels) and non-sound kernels (injured, germinated, fermented, moldy, heated, insect damaged, immature, broken, hollow, fermented up to », discolored, extraneous materials, and injured by other causes), as defined by the Brazilian Official Grading rules for corn. The non-sound kernels showed the highest contamination levels in all samples. The contamination levels of non-sound kernels (20 percent of total weight) ranged from 23 to 1,365 æg/kg of aflatoxins (B1, B2, G1 and G2) and were higher than sound kernels (p<1 percent) ranging from not detected (ND) to 126 æg/kg and in 87 percent of these the aflatoxin contents were lower than 20 æg/kg. Statistically significant correlation indexes were found among the percentage of defective groups like fermented, heated and sprouted kernels or the total injured kernels, and the estimated contamination levels for the sound and non sound fractions. It was concluded that the non-sound kernels fraction, even being small in weight, has contributed with 84 percent of the estimated contamination of the samples. The segregation of the non-sound kernels would favor a reduction in the contamination of corn lots. The poorer quality corn types (types 3 and Bellow Standart) have predominated among samples of the experiment