Simone Aparecida Galerani Mossini

Inhibitory effect of the essential oil of Curcuma longa L. and curcumin on aflatoxin production by Aspergillus flavus Link

Aflatoxins are highly toxic, mutagenic, teratogenic and carcinogenic mycotoxins. Consumption of aflatoxin-contaminated food and commodities poses serious hazards to the health of humans and animals. Turmeric, Curcuma longa L., is a native plant of Southeast Asia and has antimicrobial, antioxidant and antifungal properties. This paper reports the antiaflatoxigenic activities of the essential oil of C. longa and curcumin. The medium tests were prepared with the oil of C. longa, and the curcumin standard at concentrations varied from 0.01% to 5.0%. All doses of the essential oil of the plant and the curcumin standard interfered with mycotoxin production. Both the essential oil and curcumin significantly inhibited the production of aflatoxins; the 0.5% level had a greater than 96% inhibitory effect. The levels of aflatoxin B(1) (AFB(1)) production were 1.0 and 42.7 μg/mL, respectively, for the samples treated with the essential oil of C. longa L. and curcumin at a concentration of 0.5%.

Antifungal activity and inhibition of fumonisin production by Rosmarinus officinalis L. essential oil in Fusarium verticillioides (Sacc.) Nirenberg

The chemical composition of Rosmarinus officinalis L. essential oil (REO) was analysed by gas chromatography-mass spectrometry and nuclear magnetic resonance spectroscopy. The main compounds of the REO were 1.8 cineole (52.2%), camphor (15.2%) and α-pinene (12.4%). The mycelial growth of Fusarium verticillioides (Sacc.) Nirenberg was reduced significantly by 150 μg/mL of REO. Significant microscopic morphological changes were visualised, such as the rupture of the cell wall and the leakage of cytoplasm at 300 μg/mL of REO. At lower concentrations of REO, the effects on the production of ergosterol and the biomass of mycelium varied, as did the effects on the production of fumonisins, but at ≥300 μg/mL of REO, these processes were significantly inhibited, showing the effectiveness of the REO as an antifungal agent. The results suggested that the REO acts against F. verticillioides by disrupting the cell wall and causing the loss of cellular components, subsequently inhibiting the production of fumonisins and ergosterol.

Effect of Zingiber officinale essential oil on Fusarium verticillioides and fumonisin production

The antifungal activity of ginger essential oil (GEO; Zingiber officinale Roscoe) was evaluated against Fusarium verticillioides (Saccardo) Nirenberg. The minimum inhibitory concentration (MIC) of GEO was determined by micro-broth dilution. The effects of GEO on fumonisin and ergosterol production were evaluated at concentrations of 500-5000 μg/mL in liquid medium with a 5mm diameter mycelial disc of F. verticillioides. Gas chromatography-mass spectrometry showed that the predominant components of GEO were α-zingiberene (23.9%) and citral (21.7%). GEO exhibited inhibitory activity, with a MIC of 2500 μg/mL, and 4000 and 5000 μg/mL reduced ergosterol biosynthesis by 57% and 100%, respectively. The inhibitory effect on fumonisin B1 (FB1) and fumonisin B2 (FB2) production was significant at GEO concentrations of 4000 and 2000 μg/mL, respectively. Thus, the inhibition of fungal biomass and fumonisin production was dependent on the concentration of GEO. These results suggest that GEO was able to control the growth of F. verticillioides and subsequent fumonisin production.

Effect of Neem Leaf Extract and Neem Oil on Penicillium Growth, Sporulation, Morphology and Ochratoxin A Production

In vitro trials were conducted to evaluate the effect of Azadirachta indica (neem) extracts on mycelial growth, sporulation, morphology and ochratoxin A production by P. verrucosum and P. brevicompactum. The effect of neem oil extract from seeds and leaf was evaluated at 0.125; 0.25 and 0.5% and 6.25 and 12.5 mg/mL, respectively, in Yeast Extract Sucrose (YES) medium. Ochratoxin A production was evaluated by a thin-layer chromatography technique. Oil extracts exhibited significant (p ≤ 0.05) reduction of growth and sporulation of the fungi. No inhibition of ochratoxin A production was observed. Given its accessibility and low cost, neem oil could be implemented as part of a sustainable integrated pest management strategy for plant disease, as it has been shown to be fungitoxic by inhibition of growth and sporulation.

The Inhibitory Effects of Curcuma longa L. Essential Oil and Curcumin on Aspergillus flavus Link Growth and Morphology

The essential oil from Curcuma longa L. was analysed by GC/MS. The major components of the oil were ar-turmerone (33.2%), α-turmerone (23.5%) and β-turmerone (22.7%). The antifungal activities of the oil were studied with regard to Aspergillus flavus growth inhibition and altered morphology, as preliminary studies indicated that the essential oil from C. longa inhibited Aspergillus flavus Link aflatoxin production. The concentration of essential oil in the culture media ranged from 0.01% to 5.0% v/v, and the concentration of curcumin was 0.01–0.5% v/v. The effects on sporulation, spore viability, and fungal morphology were determined. The essential oil exhibited stronger antifungal activity than curcumin on A. flavus. The essential oil reduced the fungal growth in a concentration-dependent manner. A. flavus growth rate was reduced by C. longa essential oil at 0.10%, and this inhibition effect was more efficient in concentrations above 0.50%. Germination and sporulation were 100% inhibited in 0.5% oil. Scanning electron microscopy (SEM) of A. flavus exposed to oil showed damage to hyphae membranes and conidiophores. Because the fungus is a plant pathogen and aflatoxin producer, C. longa essential oil may be used in the management of host plants.

Pesticide use and cholinesterase inhibition in small-scale agricultural workers in southern Brazil

A controlled cross-sectional study of family growers of fruit and vegetables was conducted between October 2009 and October 2010 to characterize the use of pesticides, establish the socio-demographic profile, and analyze cholinesterase activity in small-scale agricultural workers in Southern Brazil. Data was collected for 173 workers and 179 controls. A structured questionnaire was applied collecting socio-demographic information and determining knowledge and work practices in relation to pesticide use. The benchmarks for total cholinesterase (ChEs) and butyrylcholinesterase (BuChE) were obtained from the average enzymatic activity of the occupationally unexposed group (control). The mean age of the exposed population was 40.0 ± 11.2 years. The symptoms differed significantly (p 30%) of ChEs activity, whereas no workers showed high inhibition (>50%) of BuChE. Potential factors involved include gender, education, pesticide orientation, exposure, and hygiene measures.

Trace metal levels in serum and urine of a population in southern Brazil

This study aimed to evaluate serum and urine concentrations of several trace metals of a non-directly exposed population in southern Brazil and establish reference values. Serum and urine samples were obtained from 240 volunteers (175 males and 65 females, age ranging from 18 to 74 years old). Levels of arsenic, chromium, cobalt, copper, lead, nickel, manganese and zinc were determined by means of dynamic reaction cell inductively coupled plasma mass spectrometry (DRC-ICP-MS). Comparison between genders resulted in no significant difference for all metals but serum copper, as concentrations are higher in females than males. For most metals assessed, a negative correlation between serum concentrations and age was found, but no significant correlation was found between urine concentrations and age.

Cholinesterases Inhibition by Novel cis- and trans-3-Arylaminocyclohexyl N,N-Dimethylcarbamates: Biological Evaluation and Molecular Modeling

The present study describes the synthesis, assessment of the anticholinesterase activity and the inhibition type of novel cis- and trans-3-arylaminocyclohexyl N,N-dimethylcarbamates. In vitro inhibition assay by Ellmans method with human blood samples showed that carbamates were selective for butyrylcholinesterase (BuChE) with compound concentration that inhibits 50% of enzyme activity (IC50) between 0.11 and 0.18 mmol L-1. cis- and trans-3-(4-Methoxyphenylamino)cyclohexyl N,N-dimethylcarbamate hydrochloride were the most active for BuChE, showing that the presence of methoxyl group enhanced the anticholinesterase activity. The enzyme kinetics studies indicate a noncompetitive inhibition against acetylcholinesterase (AChE) and mixed type inhibition for BuChE. Molecular modeling studies confirm the ability of carbamates to bind both the active and peripheral sites of the BuChE.

Molecular modeling and anticholinesterasic activity of novel 2-arylaminocyclohexyl N,N-dimethylcarbamates

This work reports a detailed theoretical and experimental study of the novel isomer series cis- and trans-2-arylaminocyclohexyl N,N-dimethylcarbamates as potential inhibitors of cholinesterases. In vitro inhibition assay by Ellmans method with human blood samples showed that the new carbamates are selective to the inhibition of enzyme butyrylcholinesterase (BuChE) with maximum inhibition of 90% and IC50 of 6 and 8 mmol L-1 for the more actives compounds of the series. Molecular modeling studies point to significant differences for the conformations of the compounds in the active sites of enzymes BuChE and acetylcholinesterase (AChE). The results show that the compounds interact more effectively with the active site of enzyme BuChE since the carbamate group is close to the key residues of the catalytic triad.

Effect of Zingiber officinale Roscoe essential oil in fungus control and deoxynivalenol production of Fusarium graminearum Schwabe in vitro

ABSTRACT Members of the Fusarium genus are capable of contaminating agricultural commodities, compromising the quality of maize and other grains, which leads to severe quality and yield losses. Contamination with mycotoxins is also a concern. Essential oils are possible alternatives to the use of synthetic pesticides for control of fungal contamination, as many have antifungal and anti-mycotoxigenic properties and are innocuous to human health. They also do not cause any sort of microbial resistance and do not promote environmental pollution. The aim of this study was to evaluate the antifungal and anti-mycotoxigenic effects of Zingiber officinale Roscoe essential oil (GEO) upon Fusarium graminearum Schwabe in vitro. The essential oil was extracted by hydrodistillation and analysed by GC/MS. Antifungal and anti-mycotoxigenic activities were assessed by HPLC/UV by quantifying ergosterol and deoxynivalenol (DON), respectively. Results indicated that GEO inhibited ergosterol production at a concentration of 1000 µg/mL and DON production at a concentration of 500 µg/mL, evidencing that the anti-mycotoxigenic effect is independent of the antifungal effect due to its probable direct action upon toxin biosynthesis.