Abstract Background: Extracellular vesicles (EVs) are small membrane-bound vesicles of growing interest in vetetinary parasitology. The aim of the present report was to provide the first isolation, quantification and protein characterization of EVs from buffalo (Bubalus bubalis) sera infected with Theileria spp. Methods: Infected animals were identified through optical microscopy and PCR. EVs were isolated from buffalo sera by size-exclusion chromatography and characterized using western blotting analysis, nanoparticle tracking analysis and transmission electron microscopy. Subsequently, the proteins from isolated vesicles were characterized by mass spectrometry. Results: EVs from buffalo sera have shown sizes in the 124-140 nm range and 306 proteins were characterized. The protein-protein interaction analysis has evidenced biological processes and molecular function associated with signal transduction, binding, regulation of metabolic processes, transport, catalytic activity and response to acute stress. Five proteins have been shown to be differentially expressed between the control group and that infected with Theileria spp., all acting in the oxidative stress pathway. Conclusions: EVs from buffaloes infected with Theileria spp. were successfully isolated and characterized. This is an advance in the knowledge of host-parasite relationship that contributes to the understanding of host immune response and theileriosis evasion mechanisms. These findings may pave the way for searching new EVs candidate-markers for a better production of safe biological products derived from buffaloes.

Conjugated linoleic acid (CLA), a fatty acid found in ruminant food products, has been associated with anticarcinogenic activity. However, its effect on cancer metabolism is unclear. In this paper we evaluated the effects of cis-9, trans-11 CLA on the metabolic profile of MCF-7 and MDA-MB-231 breast cancer cells using high-resolution magic angle spinning (HR-MAS) nuclear magnetic resonance (NMR) spectroscopy. The NMR spectra showed that phosphocholine level, a cancer malignance biomarker, was reduced in both cells treated with CLA, but the reduction was more pronounced in MCF-7 cells. The NMR spectra also showed that CLA has opposite effect on MCF-7 and MDA-MB-231 acetone metabolism. Acetone signal has been observed in the spectra of MDA-MB-231 control cells, but not in the spectra of the cells treated with 50 and 100 µM CLA. Conversely, the acetone signal is very small or not observed in the NMR spectra of MCF-7 control cells and in cells treated with 50 µM of CLA, but is very strong in the spectra of the cells treated with 100 µM of CLA. Therefore, this CLA concentration is causing a ketosis in MCF-7 cells by inducing the use of fatty acids as an energy source or by reducing acetone catabolism. These results indicate that CLA interfere in the metabolism of both cells. However, the strongest effect has been observed on the metabolism of MCF-7 cells cultivated in the presence of 100 µM CLA. Therefore, CLA could be a potential anticarcinogenic drug, especially for cells with positive estrogen receptor, such as MCF-7.

Piperlongumine is a natural amide alkaloid isolated from several species of Piper and is described in the literature as selectively cytotoxic to several cancer cell lines. Inhibiting cell migration has gained considerable interest as an approach for discovering antimetastatic agents because this process is fundamental to metastasis. Piperlongumine, selected from cell-based assay screening of NuBBE Database, inhibited the migration of MDA-MB-231 breast cancer cells with an EC50 of 3.0 ± 1.0 µM by the Boyden chamber assay. A series of five analogous compounds based on the structure of piperlongumine were designed, synthesized and evaluated in cell migration and cytotoxicity assays. The analogue designed by molecular simplification ((E)-N-acryloyl-3-(3,4,5-trimethoxyphenyl)acrylamide) was the most active of the series, with an EC50 of 1.5 ± 1 µM. Additionally, this compound was selectively cytotoxic, with a selectivity index (SI) of 4.4.

Natural peptides are outstanding as the most promising macromolecules in the search for new drugs, especially those of cyclic nature. The higher plants revealed a very peculiar composition of their cyclic peptides, which distinguish themselves by a "head-to-tail" cyclization. It is possible to define two groups of cyclic peptides from plant biomass. Those called in this review as Eucyclopeptides formed by 2-12 amino acid, and Cyclotides considered as circular polypeptides, composed of 29-37 amino acid that retain three disulfides bridges in an arrangement known as cyclic cystine knot. Searching for plant peptides should form into a subject for scientific research in the forefront of great importance for bioprospecting natural products macromolecular.