Nanoemulsion of Minthostachys verticillata essential oil. In-vitro evaluation of its antibacterial activity.

Infectious diseases constitute a problem of great importance for animal and human health, as well as the increasing bacterial resistance to antibiotics. In this context, medicinal plants emerge as an effective alternative to replace the use antibiotics. The essential oil (EO) of Minthostachys verticillata (Griseb.) Epling (Lamiaceae) has demonstrated a strong antimicrobial activity. However, its instability and hydrophobicity under normal storage conditions are limitations to its use. Nanoemulsion technology is an excellent way to solubilize, microencapsulate, and protect this compound. This study aimed to obtain a nanoemulsion based on M. verticillata EO and evaluate its antibacterial activity against Staphylococcus aureus. The EO was obtained by steam distillation. Identification and quantification of their components were determined by GC-MS revealing that the dominated chemical group was oxygenated monoterpenes. Nanoemulsions (NE) were characterized by measuring pH, transmittance, separation percentage, release profile, and morphology. The effect of NE on the growth of S. aureus and cyto-compatibility was also evaluated. The results showed that NE containing a higher percentage of tween 20 exhibited higher stability with an approximated droplet size of 10 nm. The effect of encapsulation process was evaluated by GC-MS revealing that the volatile components in EO were no affected. After 24 h, 74.24 ± 0.75% of EO was released from NE and the antibacterial activity of EO was enhanced considerably by its encapsulation. The incubation of S. aureus with the NE and pure EO, show a bacterial growth inhibition of 58.87% ± 0.99 and 46.72% ± 3.32 (p < 0.05), respectively. In addition, nanoemulsión did not cause toxicity to porcine and equine red blood cells. The results obtained showed that NE could be a potential vehicle for M. verticillata EO with promissory properties to emerge as a tool for developing advanced therapies to control and combat infections.

Effect of Sildenafil on Pre-Eclampsia-Like Mouse Model Induced By L-Name.

N(omega)-nitro-L-arginine methyl ester (L-NAME) decreases the vasodilator effect of nitric oxide (NO) and induces pre-eclampsia in mouse. Sildenafil inhibits the degradation of nitric oxide and increases vasodilation. This study aimed to determine the effects of sildenafil citrate on angiogenesis and oxidative stress at the maternal foetal interface on pre-eclampsia-like mouse model induced by L-NAME. Twenty pregnant mice were divided into four groups: (i) vehicle control; (ii) L-NAME; (iii) sildenafil; (4) L-NAME+sildenafil. L-NAME was administered from day 7 of pregnancy and sildenafil from day 8 until day 16; animals were euthanized on day 17. Placental and foetal sizes and weights were measured; lipid peroxide levels and catalase activity in placental homogenates were determined, and placental vascular endothelia were identified by lectin-histochemistry using BSA-I lectin. Western blot analysis was used to determine VEGF expression in placental homogenates. No changes were seen in placental and foetal development in mice with normal pregnancies treated with sildenafil. Treatments with L-NAME reduced significantly the placental weight and average height and decreased the percentage of the endothelial surface. These alterations may be mediated by the reduction of NO levels in trophoblastic cells, due to the inhibitory effect of L-NAME on nitric oxide synthase (NOS) synthesis. This effect was offset by the treatment with sildenafil, with an increase in the percentage of the endothelial surface. In conclusion, our results indicate that treatment with sildenafil on pre-eclampsia mouse model can be used without adverse effects on the concept and its use in the treatment of pre-eclampsia is promising.

pH-responsive hydrogels to protect IgY from gastric conditions: in vitro evaluation.

Oral administration of specific egg yolk immunoglobulin (IgY) is effective against a number of gastrointestinal pathogens. However, the activity of orally administered IgY is reduced rapidly, since IgY is sensitive to pepsin and low pH. In this study, hydrogels containing acrylamide and acrylic acid were synthesized and used to encapsulate IgY. The capacity of these structures to load, protect and release IgY and the interaction between IgY and hydrogels by FTIR spectroscopy were studied. The particle size and swelling percentage of hydrogels were highly dependent on the pH of the buffer solution. As expected, pH-sensitive hydrogels had a high IgY loading percentage (99.2 ± 12.9 mg IgY/mg hydrogel) at pH 7.4. It means that each gel piece incorporated approximately 8.4 ± 1.1 mg IgY. The results showed that the hydrogels could efficiently incorporate IgY and retain it inside the polymer network at pH <2.2. However, IgY was slowly released at basic pH and a high percentage remained inside. The IR spectra show that IgY interacts with the hydrogel in its network with extended hydrogen bonds. The present study demonstrates that hydrogels particles can efficiently incorporate the IgY but cannot show a controlled and sustained release of IgY in simulated intestinal fluid probably due to hydrophobic interactions with the polymer network. The stability of IgY in simulated gastric fluid was greatly improved by encapsulation in hydrogels. This approach provides information about a novelty method for delivery of IgY for the prevention and control of enteric diseases.

Immunohistochemical distribution of early pregnancy factor in ovary, oviduct and placenta of pregnant gilts.

Early pregnancy factor (EPF) is an immunosuppressant that promotes maternal immune system tolerance of the allogenic fetus. Little is known about localization of this factor in different tissues and nothing has been reported about localization in swine reproductive and placental tissues. We determined the concentration of EPF in serum of gilts and porcine placenta conditioned medium (PPCM). We also analyzed the expression of EPF in different reproductive tissues of pregnant gilts at 10, 30, 60 and 90 days of pregnancy. EPF concentration in serum and PPCM was determined by western blot and densitometry. EPF expression in reproductive tissue was assessed by immunohistochemistry. The highest concentration of EPF was observed at 30 days in serum and PPCM; the concentration was higher in PPCM than in serum at the stages we evaluated. All reproductive tissues from the gestational stages analyzed showed specific labeling of EPF, but this labeling did not appear in non-pregnant gilts. At 30 days pregnancy, the EPF expression in the ovary was predominantly in follicular lutein cells, probably owing to its function as a luteotrophic factor. In the oviduct, EPF was expressed in unciliated secretory epithelial cells and in the cilia of ciliated cells. In the placenta, EPF was expressed in the fetal portion (mesoderm chorioallantois and epithelium of endoderm). EPF acts as an autocrine and paracrine growth factor for the trophoblast during the peri-implantation period.