Bio-based polyurethane for tissue engineering applications: How hydroxyapatite nanoparticles influence the structure, thermal and biological behavior of polyurethane composites.

In this work, thermoset polyurethane composites were prepared by the addition of hydroxyapatite nanoparticles using the reactants polyol polyether and an aliphatic diisocyanate. The polyol employed in this study was extracted from the Euterpe oleracea Mart. seeds from the Amazon Region of Brazil. The influence of hydroxyapatite nanoparticles on the structure and morphology of the composites was studied using scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS), the structure was evaluated by Fourier transform infrared spectroscopy (FT-IR), thermal properties were analyzed by thermogravimetry analysis (TGA), and biological properties were studied by in vitro and in vivo studies. It was found that the addition of HA nanoparticles promoted fibroblast adhesion while in vivo investigations with histology confirmed that the composites promoted connective tissue adherence and did not induce inflammation. In this manner, this study supports the further investigation of bio-based, polyurethane/hydroxyapatite composites as biocompatible scaffolds for numerous tissue engineering applications.

In vitro biological action of aqueous extract from roots of Physalis angulata against Leishmania (Leishmania) amazonensis.

BACKGROUND: Leishmaniasis is an infectious disease caused by various species of the protozoan parasites of the Leishmania genus and transmitted by phlebotomine sandflies. The protozoa multiply in phagocytic cells, mainly macrophages, which play an important role defending the organism from pathogens. The most effective treatment for leishmaniasis is the chemotherapy and besides the high cost, these drugs are toxic and require a long period of treatment. Currently, some herbal products are considered an important alternative source of a new leishmanicidal agent, which includes the plant Physalis angulata, . We evaluated effects of an aqueous extract from roots of Physalis angulata (AEPa) on Leishmania proliferation, morphology and also determined whether physalins were present in the extract contributing to the knowledge of its pharmacological efficacy. METHODS: Morphological alterations were determined by light microscopy, transmission and scanning electron microscopy. Host cell viability was evaluated by MTT, and propidium iodide. AEPa were submitted in full HRESITOF analysis. RESULTS: AEPa promoted a dose-dependent reduction on promastigotes (IC50 = 39.5 µg/mL ± 5.1) and amastigotes (IC50 = 43.4 µg/mL ± 10.1) growth. This growth inhibition was associated with several morphological alterations observed in promastigote forms. No cytotoxic effect in mammalian cells was detected (IC50 > 4000 µg/mL). Furthemore, the presence of physalins A, B, D, E, F, G and H were described, for the first time, in the P. angulata root. CONCLUSIONS: Results demonstrate that AEPa effectively promotes antileishmanial activity with several important morphological alterations and has no cytotoxic effects on host cells.

Antinociceptive Activity and Toxicity Evaluation of the Fatty Oil from Plukenetia polyadenia Mull. Arg. (Euphorbiaceae).

Seed oil (Pp-oil) of Plukenetia polyadenia is used by native people of the Brazilian Amazon against arthritis and rheumatism, spreading it on the arms and legs to reduce the pain and inflammation. Pp-oil was obtained by pressing dried seeds at room temperature to give a 47.0% yield of oil. It was then subjected to fatty acid composition analysis. The principal fatty acids were linoleic acid (46.5%), α-linolenic acid (34.4%) and oleic acid (13.9%). Then, it was evaluated for its antinociceptive activity in mice, using the acetic acid-induced abdominal writhing, hot plate and formalin test models. Additionally, its toxicity was determined. The Pp-oil proved to have no toxicological effects, showing dose-dependent antinociceptive effect under chemical stimulation. At oral doses of 25-100 mg/kg, Pp-oil significantly reduced the abdominal writhes in the writhing test. A higher oral dose of 200 mg/kg did not induce alterations in the latency time of the hot plate test when compared to the control, suggesting an analgesic activity of peripheral origin. At oral doses of 50 and 100 mg/kg, the Pp-oil significantly reduced the second phase of the algic stimulus in the formalin test. In addition, the antinociception of Pp-oil was reversed by naloxone in the evaluation of its mechanism of action. Therefore, the Pp-oil proved to be safe at very high doses and to show significant analgesic properties. The role of Pp-oil is still being investigated with respect the mechanism of action, but the results suggest that opiod receptors could be involved in the antinociception action observed for the oil of P. polyadenia.

PCL/Andiroba Oil (Carapa guianensis Aubl.) Hybrid Film for Wound Healing Applications.

Developing a biomimetic material to wound care is an emerging need for the healing process. Poly (ε-caprolactone) (PCL) is a polymer with the necessary dressing's requirements often used in medicine. Their surface, physic-chemical and biological properties can be modified by adding bioactive compounds, such as andiroba seed oil (Carapa guianensis). This Amazonian natural plant has medicinal and pharmacological properties. For this purpose, PCL polymeric films incorporated with andiroba oil were investigated. The synthesis of hybrids materials was carried out in the solvent casting method. Thermal properties were evaluated using thermogravimetric analysis (TGA/DTGA) and differential scanning calorimetry (DSC). The solvent type on the surface and hydrophilicity of samples was studied using a scanning electron microscope (SEM). Additionally, contact angle measurements, functional groups analysis, fluid absorption capacity, and cell viability were performed. The results demonstrated the influences of andiroba oil under the morphology and thermal properties of the polymeric matrix; the hydrophilicity of the hybrid film obtained by acetic acid was reduced by 13%; the porosity decreased as the concentration of oil increased, but its higher thermal stability. The L929 cell line's proliferation was observed in all materials, and it presented nontoxic nature. It was demonstrated the ability of PCL hybrid film as a matrix for cell growth. Then, the materials were proved potential candidates for biomedical applications.

Pellucidin A promotes antinociceptive activity by peripheral mechanisms inhibiting COX-2 and NOS: In vivo and in silico study.

Peperomia pellucida (PP) belongs to the Peperomia genus, which has a pantropic distribution. PP is used to treat a wide range of symptoms and diseases, such as pain, inflammation, and hypertension. Intriguingly, PP extract is used by different tropical countries for its anti-inflammatory and antinociceptive effects. In fact, these outcomes have been shown in animal models, though the exact bioactive products of PP that exert such results are yet to be discovered. To determine and elucidate the mechanism of action of one of these compounds, we evaluated the antinociceptive effect of the novel dimeric ArC2 compound, Pellucidin A by using in vivo and in silico models. Animals were then subjected to chemical, biphasic and thermal models of pain. Pellucidin A induced an antinociceptive effect against chemical-induced pain in mice, demonstrated by the decrease of the number of writhes, reaching a reduction of 43% and 65% in animals treated with 1 and 5 mg/kg of Pellucidin A, respectively. In the biphasic response (central and peripheral), animals treated with Pellucidin A showed a significant reduction of the licking time exclusively during the second phase (inflammatory phase). In the hot-plate test, Pellucidin A did not have any impact on the latency time of the treated animals. Moreover, in vivo and in silico results show that Pellucidin A's mechanism of action in the inflammatory pain occurs most likely through interaction with the nitric oxide (NO) pathway. Our results demonstrate that the antinociceptive activities of Pellucidin A operate under mechanism(s) of peripheral action, involving inflammatory mediators. This work provides insightful novel evidence of the biological properties of Pellucidin A, and leads to a better understanding of its mechanism of action, pointing to potential pharmacological use.