Proteomic Profiles of Thyroid Gland and Gene Expression of the Hypothalamic-Pituitary-Thyroid Axis Are Modulated by Exposure to AgNPs during Prepubertal Rat Stages.

Silver nanoparticles (AgNPs) have potent antimicrobial activity and, for this reason, are incorporated into a variety of products, raising concern about their potential risks and impacts on human health and the environment. The developmental period is highly dependent on thyroid hormones (THs), and puberty is a sensitive period, where changes in the hormonal environment may have permanent effects. We evaluated the hypothalamic-pituitary (HP)-thyroid axis after exposure to low doses of AgNPs using a validated protocol to assess pubertal development and thyroid function in immature male rats. For stimulatory events of the HP-thyroid axis, we observed an increase in the expression of Trh mRNA and serum triiodothyronine. Negative feedback reduced the hypothalamic expression of Dio2 mRNA and increased the expression of Thra1, Thra2, and Thrb2 mRNAs. In the pituitary, there was a reduced expression of Mct-8 mRNA and Dio2 mRNA. For peripheral T3-target tissues, a reduced expression of Mct-8 mRNA was observed in the heart and liver. An increased expression of Dio3 mRNA was observed in the heart and liver, and an increased expression of Thrb2 mRNA was observed in the liver. The quantitative proteomic profile of the thyroid gland indicated a reduction in cytoskeletal proteins (Cap1, Cav1, Lasp1, Marcks, and Tpm4; 1.875 µg AgNP/kg) and a reduction in the profile of chaperones (Hsp90aa1, Hsp90ab1, Hspa8, Hspa9, P4hb) and proteins that participate in the N-glycosylation process (Ddost, Rpn1 and Rpn2) (15 µg AgNP/kg). Exposure to low doses of AgNPs during the window of puberty development affects the regulation of the HP-thyroid axis with further consequences in thyroid gland physiology.

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 ß -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.

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%.