Técnicas de descontaminação de castanhas-do-brasil intencionalmente contaminadas com Aspergillus nomius / Techniques of decontamination of brazil nuts intentionally contaminated with Aspergillus nomius

A castanha-do-brasil é uma matéria-prima de origem amazônica, conhecida por seus benefícios nutricionais. Entretanto, por conta da produção extrativista este produto está susceptivel a vários focos de contaminação durante a cadeia produtiva. Este trabalho teve como objetivos a avaliação de diferentes métodos de descontaminação para controle de Aspergillus nomius produtor de aflatoxinas em castanha-do-brasil. As amostras de castanhas foram inoculadas com suspensão de A. nomius e posteriormente, foram testadas as técnicas de secagem em estufa a 60°C por 8 horas, esterilização em cabine UV por 20 minutos e sanitização com hipoclorito de sódio a 200 ppm por 15 minutos. Todos os tratamentos tiveram ação sob a cepa, sendo obtidos reduções de 3,18; 1,66 e 1,04 RD, respectivamente. A secagem mostrou-se o melhor tratamento de descontaminação, no entanto, mais pesquisas com outros métodos de descontaminação em castanhas são necessárias para controle da contaminação fúngica.

Inhibition of Aspergillus flavus and A. Parasiticus fungal growth and its aflatoxins [B1, B2, G1 and G2] production by lactobacillus acidophillus

This study aimed to investigate the inhibition effect of two strains of Lactobacillus acidophilus ATCC4495 and Lactobacillus acidophilus ATCC20552 on Aflatoxins [AFB1, AFB2, AFG1 and AFG2] producing fungi in both of culture media and corn grains [Zea maize]. Aflatoxins [AFs], the secondary metabolites produced by species of Aspergilli, specifically Aspergillus flavus and Aspergillus parasiticus, have harmful effects on humans, animals, and crops that result in illnesses and economic losses. Both L. acidophilus strains were in vitro tested for its antifungal activity against A. flavus and A. parasiticus individually. The results indicated that both of strains showed antifungal activity against tested fungi. The cell free supernatant of L. acidophilus ATCC4495 recorded stronger inhibition against A. flavus [11.5m] and A. parasiticus [13m] while L. acidophilus ATCC20552 was less active. In addition, the activity was decreased by diluting the supernatant, for both L. acidophilus strains. Corn grains treated with original supernatant [100%] recorded the lowest total damage percentage during 30 days of storage at room temperature. Strain L. acidophilus ATCC4495 recorded high activity against two fungal strains. Corn grains treated only with LAB supernatant [negative controls] recorded the lowest aflatoxins content followed by infected grains with either A. flavus or A. parasiticus treated with cell free supernatant of L. acidophilus ATCC4495, followed by L. acidophilus ATCC20552, while infected grains with A. flavus or A. parasiticus [positive controls] contained the highest aflatoxins content

Inactivación de aflatoxina B1 y aflatoxicol por nixtamalización tradicional del maíz y su regeneración por acidificación de la masa / Inactivation of aflatoxin B1 and aflatoxicol through traditional

OBJETIVO: Confirmar el efecto de la nixtamalización tradicional sobre la aflatoxina, identificar el compuesto remanente en masa, evaluar su toxicidad y su regeneración por tratamiento ácido. MATERIAL Y MÉTODOS: Se utilizó maíz, sin y con aflatoxina, y se nixtamalizó. La toxicidad se evaluó en pollos de ocho días de edad. Se aplicó el tratamiento ácido a la masa. La cuantificación de aflatoxinas se realizó por cromatografía líquida de alta resolución (HPLC). RESULTADOS: La nixtamalización destruyó la aflatoxina (96 por ciento) y el aflatoxicol (70 por ciento); el remanente en masa fue aflatoxina B1. El tratamiento ácido in vitro no eleva las concentraciones de ninguna de las dos micotoxinas. Los pollos murieron al ingerir 260 mg de AFB1, y la masa con aflatoxina remanente no fue tóxica. CONCLUSIONES: Los resultados ilustran el beneficio de la nixtamalización tradicional en la inactivación de las aflatoxinas presentes en maíz y en su no reconstitución por efecto del tratamiento ácido.

Synthesis and biological evaluation of 1,2,4 triazole and 1,3,4-Oxa-and Thiadiazoles derivatives

The alkaline hydrolysis with dimethylsulfate and potassium hydroxide of coumarin-6-derivatives [Ia-d] yielded 3-propenoic acid derivatives [IIa-d] which in turn were reached with thionyl chloride in toluene to give carbonyl chloride derivatives [IIa-d]. The latter compounds condensed with thiosemicarbazide in dioxane to give carbonylthiosemicarbazide derivatives [IVa-d], respectively. Cyclization of IVa-d, using sodium hydroxide yielded 5-mercapto- 1,2,4-triazol-3-yl-derivatives [Va-d]. Cyclodehydration of IVa-d using ortho-phosphoric acid or dicyclohexylcarbodiimide [DCC] led to the formation of the corresponding 5-amino-1,3,4-thia and oxadiazol-2-derivatives [VIa-d] and [VIIa-d], respectively. The antimicrobial and antiaflatoxigenic activities of Va-d, VIa-d were also evaluated

Steroid hormones retard aflatoxin-induced cytotoxicity.

Protective effect of sex steroid hormones on aflatoxin-induced cytotoxicity on RBC (hemolysis) was examined in vitro. Addition of aflatoxin (2 micrograms/ml) in RBC suspension caused significant increase in hemolysis. Concurrent addition of aflatoxin (2 micrograms/ml) and estradiolbenzoate (100-1200 pg/ml) in RBC suspension significantly retarded aflatoxin-induced hemolysis. Similarly, addition of aflatoxin (2 micrograms/ml) along with testosterone propionate (5-60 ng/ml) in RBC suspension retarded aflatoxin-induced hemolysis. Among the two synthetic hormones studied estradiolbenzoate was more potent than testosterone propionate.

Inhibitory effect of boric acid on the development and aflatoxin production by aspergillus flavus and aspergillus parasiticus

El ácido bórico fué analizado en las concentraciones de 0,25 porciento; 0,5 porciento y 1,0 porciento, demostrando su eficacia al inhibir el crecimiento de Aspergillus flavus (NRRL 3251 y NRRL 5520) y Aspergillus parasiticus (UNBF A12 y NRRL 2999), como tambien la producción de aflatoxinas. Los resultados sugieren que este aditivo es eficiente en el control de hongos del grupo A. flavus inhibiendo el crecimiento de los mismos en la concentración máxima permitida por la legislación brasileña (0,5 porciento)

Inhibition of aflatoxin production & growth of Aspergillus flavus by eugenol & onion & garlic extracts.

Efficacy of natural non-toxic materials including extracts of onion and garlic as well as eugenol was tested against aflatoxin production by A. flavus in liquid SMKY medium and in maize grains. Maximum inhibition in the mycelial growth occurred with garlic extract (61.94%), whereas inhibition of aflatoxin production was highest (60.44%) due to onion extract. Eugenol was most suitable for inhibiting aflatoxin production (60.35%) on maize grains.

Substâncias antifúngicas, inibidoras de Aspergillus flavus e de outras espécies fúngicas, isoladas de Agave sisalana (sisal) / Antifungal substances, inhibitor of Aspergillus flavus and other fungal species, isolated from Agave sisalana (sisal)

Foram isoladas e caracterizadas parcialmente substâncias antifúngicas a partir de folhas de Agave sisalan (sisal). A atividade inibidora do suco das folhas de sisal foi pronunciada contra Cryptococcus neoformans, Crebrothecium ashbyi e Saccharomyces cerevisiae e menos ativa contra Penicillium chrysogenum, Aspergillus flavus (produtor de aflatoxinas) e A. oryzae. Para o controle rotineiro dos métodos de isolamento do princípio ativo do sisal foi preferido o S. cerevisiae, devido à rapidez do crecimento, inocuidade e sensibilidade. Por meio de participaçäo em solventes e precipitaçöes, foi obtida a sisalanina complexa, que por meio de cromatografia em coluna, foi separada em sete glicosídios designados sisalaninas A, B, C, D, E, F e G. A sisalanina B é constituída de hecogenina, glicose, talactose e xilose, e a sisalanina D dos mesmos compostos e mais a ramnose. A primeira é cerca de quatro vezes mais ativa que a segunda e duas vezes e meia mais que a sisalanina complexa. As concentraçöes inibitórias mínimas da sisalina complexa em ppm determinadas contra fungos säo: A. flavus, 100; A, niger, 1.600; A oryzae, 100; A. parasiticus, 100; Candida albicans, 50; Rhodotorula glutinis, 100 e S.cerevisiae, 12

Modification of aflatoxin B1-induced changes in certain mitochondrial enzymes and lipids by medroxyprogesterone acetate.

The effect of a single dose of 5 mg/kg body weight of aflatoxin B1 on rat liver mitochondrial enzymes, succinate dehydrogenase (SDH) and Mg++ adenosine triphosphatase (Mg++-ATPase) and on certain lipids were studies at various intervals of time from 3 to 24 hours. A significant decrease in the specific activity of SDH was observed after 6, 12, 18 and 24 hr treatment. The Mg++-ATPase activity remained unaffected up to 12 hr but appreciably decreased after, 18 and 24 hr of the treatment. The level of phospholipids and cholesterol were not altered after 3, 6 and 12 hr treatment, thereafter (18 and 24 hr) an increase was observed in both the lipids following the aflatoxin treatment. Medroxyprogesterone acetate (MPA) did not cause any alteration in the specific activities of these enzymes as well as levels of cholesterol and phospholipids. The treatment with MPA caused significant increase in contents of cytochromes P-450, b5 and activities of Arylhydrocarbon hydroxylase (AHH), UDP-glucuronyl transferase (UDP-GT) and NADPH-cytochrome C-reductase of hepatic microsomes. It was observed that pretreatment with medroxyprogesterone acetate (MPA) could significantly minimuze the depression caused in mitochondrial SDH and Mg++-ATPase activities by aflatoxin B1.

Los efectos inhibitorios del ethoxiquin sobre la acción carcinogénica de la aflatoxina B1 en las ratas / Inhibitory effects of ethoxyguin on the carcinogenic action of the aflatoxin B1 in female rats

Etoxiquin (EQ), un antioxidante muy frecuentemente utilizado, inhibe los efectos carcinogénicos de los hidrocarburos policiclicos aromáticos. La finalidad de este estudio es determinar si la administración de EQ modifica los efectos hepatocarcinogénicos de la aflatoxina B1 (AFB1) en las ratas. Las ratas, en distintos grupos, recibieron en su dieta, ya sea: (a) EQ durante 2 semanas, seguido de AFB1 durante 6 semanas; (b) EQ y AFB1 simultáneamente; (c) EQ después de terminado el tratamiento con AFB1. Los resultados indican que EQ puede inhibir los efectos hepatocarcinogénicos de la AFB1 y que la inhibicón más efectiva es la que se obtiene cuando EQ y AFB1 son administrados simultáneamente. Nuestros resultados muestran también que el grado de protección desaparece cuando las ratas son tratadas con EQ y luego, durante un período de recuperación de 4 semanas, son sometidas a la dieta de control antes de recibir la AFB1. En este grupo la incidencia de las lesiones neoplásicas en el higado no difiere de la del grupo de ratas que habia recibido solamente AFB1. El efecto inhibitorio del EQ en la carcinogénesis inducida por la AFB1 es de interés. Sin embargo, antes de poder realizar una evaluación global sobre la utilidad de EQ en la quimioprevención es necesario efectuar ulteriores investigaciones