Toxicity evaluation of traditional and organic yerba mate (Ilex paraguariensis A. St.-Hil.) extracts.

Yerba mate (Ilex paraguariensis A. St.-Hil.) is an important source of biologically active compounds with pharmacological potential. The aim of this study was to examine the toxicity of different extracts obtained from either traditional or organic cultivated yerba mate in vitro and in vivo. Aqueous, ethanolic and methanolic extracts were obtained from commercial samples of yerba mate and total phenolic content was determined employing Folin-Ciocalteau reagent. The aqueous extracts presented higher content of total phenols, compared to ethanolic and methanolic extracts, and also demonstrated lower cytotoxicity, which is the basis for testing were carried out only using aqueous extracts. The main phenolic acids found in traditional aqueous (TA) extract were chlorogenic, gallic and protocatechuic acids. Gallic and hydroxybenzoic acids were detected in aqueous cultivated organic (OA) extract. Pretreatment with OA extract (100 µg/ml, 1 hr) was cytoprotective against rotenone-induced toxicity (1 µM). For in vivo toxicity assay, zebrafish embryos were exposed to OA or TA extracts (10-160 µg/ml) at 4 hr post fertilization. TA extract decreased embryos survival in a concentration-dependent manner, reduced the hatching rate at 40 µg/ml, increased edema frequency at 80 µg/ml and altered body curvature at 120 µg/ml. Further, TA extract produced locomotor disorders at concentrations equal to or greater than 10 µg/ml. In contrast, OA extract exhibited no apparent toxic effect on organogenesis and behavior up to 100 µg/ml. In summary, the OA cultivated extract showed the lowest cytotoxicity in vitro, enhanced reduction in rotenone-induced toxicity, and produced less toxicity in zebrafish embryos compared to the TA extract.

Phenolic compounds and antioxidant capacity of Pediastrum boryanum (Chlorococcales) biomass.

Bioactive compounds, synthesized by photosynthetic microorganisms, have drawn the attention of the pharmaceutical field. This study aimed at evaluating synthesis and in vitro antioxidant capacity of phenolic compounds produced by a microalgae species P. boryanum, which was grown in six different culture media (standard BG11, modified BG11/MBG11, standard WC, modified WC, WC*2 and basal). The highest concentrations of biomass (1.75 ± 0.01 g.L-1) and phenolic content (3.18 ± 0.00 mg.g-1) were obtained when P. boryanum was grown in MBG11 and phenolic acids were identified: gallic, protocatechuic, chlorogenic, hydroxybenzoic and vanillic ones. All extracts exhibited scavenger activity in the ABTS assay and inhibited peroxidase. However, phenolic compounds from P. boryanum grown in BG11 and MBG11 had the most potent scavenger activity in the DPPH assay. In sum, P. boryanum can be a new source of free phenolic compounds with potential antioxidant activity when grown in MBG11, since it yields high amounts of biomass and phenolic compounds.

Evaluation of the influence of cultivation on the total magnesium concentration and infusion extractability in commercial arabica coffee.

Coffee is considered an important source of organic nutrients and minerals, and these resources are strongly affected by agricultural management. Among the minerals, the element Mg is important, which is essential for both plants and humans. In this work, the effects of agricultural management on the absorption and storage of Mg by commercial, ground, roasted Arabica coffee were investigated. For this purpose, some Mg and P fractions were evaluated. It was observed that Mg stored in the grain was concentrated in the inorganic fraction, with an average extraction of 102% and in conventional samples and 119% in organic samples. These results suggest that in these samples Mg is probably largely presented as different inorganic salts. Phytate and organic acid salts are two possibilities discussed in this work that could explain this hypothesis. This can be corroborated by the extraction of Mg in the infusion of hot water.

Antioxidant and antifungal activity of phenolic compounds and their relation to aflatoxin B1 occurrence in soybeans (Glycine max L.).

BACKGROUND: Soybean is widely used in food formulations; however, few studies on fungal or mycotoxin contamination have been undertaken. Free, conjugated, and bound phenolic compounds, and their antioxidant and antifungal potential, were therefore evaluated together with the occurrence of aflatoxin B1 (AFB1 ) in soybeans. RESULTS: The conjugated and bound phenolic soybean extracts were more efficient for the inhibition of the 2,2 diphenyl-1-picryl-hydrazyl (DPPH) radical, the peroxidase enzyme, and the fungal α-amylase enzyme. Aflatoxin B1, detected at low levels (0.96 to 1.67 ng g-1 ), confirmed the protective effect of soybean phenolic compounds against mycotoxigenic contamination. Principal component analysis confirmed that syringic, p-hydroxybenzoic, p-coumaric acids and vanillin were essential for antioxidant and antifungal activities. CONCLUSION: This study presented new insights into the functionality of phenolic compounds in soybeans, regarding their potential to protect the crops naturally against fungal contamination, avoiding aflatoxin production, as attested by the correlations between phenolic compounds and antioxidant mechanisms. © 2019 Society of Chemical Industry.

Effect of natural compounds on Fusarium graminearum complex.

BACKGROUND: A search is underway for new solutions to counter farm loss caused by fungal contamination of grains, since the active agents of fungicides can remain in the environment and contribute to the development of resistant and toxigenic species. In this study, the antifungal activity of natural compounds (γ-oryzanol, phenolic extract of neem seeds and of rice bran) was assessed on three toxigenic strains of Fusarium graminearum isolated from wheat, rice and barley. Their efficacy was compared to that of synthetic fungicides. The halo diameters were measured and the susceptible pathways were determined by the levels of structural compounds and activities of enzymes involved in the primary metabolism of the microorganisms. Moreover, mycotoxin production and gene expression were examined. RESULTS: Phenolic extracts were more effective at inhibiting F. graminearum than was γ-oryzanol, as evidenced by the minimum inhibitory concentration. This work contributed to the elucidation of the mechanism of action of natural antifungal agents. CONCLUSION: Natural antifungals effectively inhibited fungal growth, especially via the inactivation of the enzymatic systems of F. graminearum. Natural antifungals inhibited mycotoxin production by the fungi. A correlation between the levels of deoxynivalenol and the expression of Tri5 gene was observed, indicating that the natural compounds could be considered alternatives to synthetic antifungals. © 2015 Society of Chemical Industry.

Emprego de casca de arroz como adsorvente para execução de técnica de MSPD para determinar aflatoxinas em cebolas / Use of rice husk as an adsorbent for performing MSPS techinique for determining the aflatoxins occurrence in onion

Foi estudada a extração simultânea de aflatoxinas (AFLAs) B1, B2, G1 e G2 em cebolas por meio de técnica de dispersão da matriz em fase sólida (MSPD), utilizando-se a casca de arroz como adsorvente. A identificação e quantificação das aflatoxinas foram realizadas empregando-se cromatografia em camada delgada de alta eficiência (CCDAE) e cromatografia líquida de alta eficiência acoplada ao detector de fluorescência (CLAE-FL). O melhor adsorvente foi constituído de mistura de casca de arroz: terra diatomácea (1:1)(p/p), empregado na proporção de 1:1 (p/p) com a massa de amostra e a mistura clorofórmio: metanol (5:25) (v/v) como eluente. A metodologia mostrou limites de detecção que variaram de 0,05 a 1 μg.kg-1,de exatidão entre 78 e 93 por cento, e coeficientes de variação compreendidos entre 11 e 14 por cento. Após a validação, a metodologia foi testada quanto à sua aplicabilidade para determinar a ocorrência das aflatoxinas em amostras de cebola, as quais foram classificadas segundo a norma do MAPA. A contaminação com aflatoxina foi verificada em 43 por cento das amostras analisadas com teor máximo de 90μg.kg-1 de AFLAB2.

Estudo das condições de extração de compostos fenólicos de cebola (Allium cepa L. ) / Study on the extracting conditions of phenolic compounds from onion (Allium cepa L)

O objetivo deste trabalho foi estabelecer as melhores condições para efetuar extração de compostos fenólicos totais de diferentes classes comerciais de cebola (Allium cepa L.). Por meio de Planejamento Experimental Fatorial foram determinadas as variáveis que influenciam significativamente nas etapas de extração. As variáveis estudadas foram: natureza do solvente, procedimento de agitação, tempo de extração e tempo de agitação com e sem interrupções. A melhor combinação resultou em um modelo preditivo, empregando semetanol como solvente, agitação de 120 minutos a 200 rpm. O maior conteúdo fenólico em diferentes classes de cebola foi 2275 μg/g, 88% de recuperação e o limite de quantificação foi de 31 μg fenóis/g.