Antifungal activity of terpenes isolated from the Brazilian Caatinga: a review.

Terpenoids, also named terpenes or isoprenoids, are a family of natural products found in all living organisms. Many plants produce terpenoids as secondary metabolites, and these make up a large part of essential oils. One of most important characteristic is that the compounds are volatile, have odor and can be used in a variety of applications in different industrial segments and traditional medicine. Brazil has a rich and diverse flora that can be used as a source of research for obtaining new molecules. Within the Brazilian flora, it is worth mentioning the Caatinga as an exclusively Brazilian biome where plants adapt to a specific series of weather conditions and therefore become a great storehouse of the terpenoid compounds to be described herein. Fungal infections have become increasingly common, and a great demand for new agents with low toxicity and side effects has thus emerged. Scientists must search for new molecules exhibiting antifungal activity to develop new drugs. This review aims to analyze scientific data from the principal published studies describing the use of terpenes and their biological applications as antifungals.

Effect of the photoinitiator system on the polymerization of secondary methacrylamides of systematically varied structure for dental adhesive applications.

OBJECTIVE: The aim of this study was to investigate the influence of the photoinitiator system on the polymerization kinetics of methacrylamide-based monomers as alternatives to methacrylates in adhesives dental-based materials. METHODS: In total, 16 groups were tested. Monofunctional monomers (2-hydroxyethyl methacrylate) - HEMA; (2-hydroxy-1-ethyl methacrylate) -2EMATE, (2-hydroxyethyl methacrylamide) - HEMAM; and (N-(1-hydroxybutan-2-yl) methacrylamide) -2EM; were combined with bifunctional monomers containing the same polymerizing moieties as the monofunctional counterparts (HEMA-BDI; 2EMATE-BDI; HEMAM-BDI; and 2EM-BDI) at 50/50 M ratios. BHT was used as inhibitor (0.1 wt%) and the photoinitiators used were: CQ + EDMAB (0.2/0.8), BAPO (0.2), IVOCERIN (0.2), and DMPA (0.2), in wt%. The polymerization kinetics were monitored using Near-IR spectroscopy (∼6165 cm-1) in real-time while the specimens were photoactivated with a mercury arc lamp (Acticure 2; 320-500 nm, 300 mW/cm2) for 5 min, and maximum rate of polymerization (Rpmax, in %.s-̄1), degree of conversion at Rpmax (DC@Rpmax, in %), and the final degree of conversion (Final DC, in %) were calculated (n = 3). Initial viscosity was measured with an oscillating rheometer (n = 3). Data were analyzed using Two-way ANOVA for the polymerization kinetics and one-way ANOVA for the viscosity. Multiple comparisons were made using the Tukey's test (∝ = 0.05). RESULTS: There was statistically significant interaction between monomer and photoinitiator (p < 0.001). For the methacrylates groups, the highest Rpmax was observed for HEMA + DMPA and 2EMATE + BAPO. For methacrylamides groups, the highest Rpmax were observed for HEMAM and 2EM, both with DMPA. Final DC was higher for the methacrylate groups, in comparison with methacrylamide groups, independent of the photoinitiators. However, for the methacrylamide groups, the association with BAPO led to the lowest values of DC. In terms of DC@Rpmax, methacrylate-based systems showed significantly higher values than methacrylamide formulations. DMPA and Ivocerin led to higher values than CQ/EDMAB and BAPO in methacrylamide-based compounds. BAPO systems showed de lowest values for both HEMA and HEMAM formulations. For the viscosity (Pa.s), only 2EM had higher values (1.60 ± 0.15) in comparison with all monomers. In conclusion, polymerization kinetics was affected by the photoinitiators for both monomers. Viscosity was significantly increased with the use of secondary methacrylamide. SIGNIFICANCE: this work demonstrated the feasibility of using newly-synthesized methacrylamide monomers in conjunction with a series of initiator systems already used in commercial materials.

Effect of the addition of thiourethane oligomers on the solâ¿¿gel composition of BisGMA/TEGDMA polymer networks.

OBJECTIVES: Thiourethane oligomers have been shown to increase the fracture toughness and reduce the polymerization stress of methacrylate-based materials. However, network formation has not been elucidated in these materials yet. The aim of this study was to evaluate how the addition of a thiourethane oligomer (TU) influences the sol/gel composition and network structure of methacrylate-based materials using dynamic mechanical analysis and extraction methods. MATERIALS AND METHODS: BisGMA/TEGDMA at systematically varied mass ratios (20/80 to 80/20wt%) were mixed with pre-polymerized thiourethane oligomers at 0 (control) or 20wt%, synthesized by combining pentaerythritol tetra-3-mercaptopropionate with dicyclohexylmethane 4,4⿲-Diisocyanate, at 1:2 isocyanate:thiol. 0.1wt% of 2,2-Dimethoxy-2-phenylacetophenone was added as the photoinitiator and 0.3wt% of 2,6-di-tert-butyl-4-methylphenol was added as a free radical inhibitor. Disk specimens (0.8ÿ10mm in diameter, n=3) were photoactivated at 270mW/ (320â¿¿500nm) for 1min. The degree of conversion (DC) was measured in near-IR (Ë¿6165cmâ¿¿1). Specimens were immersed in two different solvents (water for 7 days or dicholoromethane for 48h). Water sorption (WS) and solubility (SL) were obtained according to ISO 4049. The leachates for both solutions were analyzed with 1H-NMR (400MHz, CDCL3). Bar specimens (1ÿ3ÿ25mm, photocured and then post-processed at 180°C for 8h to DC>95%) were subjected to dynamic mechanical analysis (â¿¿30 to 230°C) to obtain glass transition temperature (Tg), tan delta curves and crosslinking density (ν). Data was analyzed with two-way ANOVA/Tukeyâ¿¿s test (95%). RESULTS: In general, the presence of TU increased the overall conversion. The WS was similar for all groups, but the SL decreased by 2-fold with the addition of the TU oligomer for all compositions, except BisGMA/TEGDMA 80/20. The BisGMA concentration of the leachates increased with increasing BisGMA in the initial mixture, and with the presence of thiourethane. This compositional drift of the gel with the presence of TU was attributed to the preferential dissolution of TEGDMA into the TU network. Tg and ν decreased with the addition of TU, as expected. The addition of TU produced more homogeneous networks, as evidenced by narrower breadth of the tan delta curve. CONCLUSION: The addition of TU affected the composition of the sol/gel in crosslinked networks, which were more homogeneous and presented 2-fold less potentially toxic leachates than the methacrylate controls. CLINICAL SIGNIFICANCE: The addition of TU may produce less cytotoxic materials based on the increased conversion and reduced amount of unreacted extractables from its network after water storage.

[Vasoactive endothelial factors]. / Factores endoteliais vasoactivos.

Endothelium-derived vasoactive factors are produced by the endothelium activated by effective stimulus, and with paracrine regulatory activity of the tone/proliferation of the vascular smooth muscle and platelet function. They are divided in two groups: endothelium-derived relaxing and contracting factors. Among the endothelium-derived relaxing factors, PG I2, EDRF (NO or other nitrous compound) and EDHF (still unidentified) have been considered Synthetized by the endothelium after stimulation by plasmatic, platelet-derived and endothelium-derived substances and mechanisms, towards the vascular smooth muscle (myorelaxing/cytostatic) and the platelets (antiaggregation). The endothelium-derived contracting factors include the EDCF1 (endothelins, 21 amino acids peptides), EDCF2 (O2-) and TxA2. Its production, induced by stimulus similar to those for relaxing factors, promotes constriction/mitogenesis of the vascular smooth muscle and platelet aggregation. Probably, endothelin-1 has indirect actions over hormonal mechanisms of cardiovascular and renal regulation. The vascular system establishes a tight regulation over the production of these endothelium-derived vasoactive factors. Its loss (usually due to alteration of endothelial responsiveness to stimulation) allows local or generalized modifications of the vascular tone. These can depend on hypertension, atherosclerosis, ischemia-reperfusion lesion, diabetes, inflammation and situations of farmacotoxicity (all developing vasoconstriction/vasospasm) or by septicemia (leading to vasodilation). This disregulation is also involved in the pathogenesis of hypertension, atherosclerosis and ischemia-reperfusion. The vascular tone regulation by endothelium also leads to systemic consequences. Essentially by decreasing cardiac, cerebral and renal blood flow it implies morphologic and functional modifications of these organs.