The aim of this study was to evaluate the effect of camphorquinone concentration in physical-mechanical properties of experimental flowable composites in order to find the concentration that results in maximum conversion, balanced mechanical strength, and minimum shrinkage stress. Model composites based on BISGMA/TEGDMA with 70% wt filler loading were prepared containing different concentrations of camphorquinone (CQ) on resin matrix (0.25%, 0.50%, 1%, 1.50%, and 2% by weight). Degree of conversion was determined by FTIR. Surface hardness was assessed before and after 24 h ethanol storage and softening rate was determined. Depth of cure was determined by Knoop hardness evaluation at different depths. Color was assessed by reflectance spectrophotometer, employing the CIE-Lab system. Flexural strength and elastic modulus were determined by a three-point bending test. Shrinkage stress was determined in a Universal Testing Machine in a high compliance system. Data were submitted to ANOVA and Tukey's test (α = 0.05). The increase in CQ concentration caused a significant increase on flexural strength and luminosity of composites. Surface hardness was not affected by the concentration of CQ. Composite containing 0.25% wt CQ showed lower elastic modulus and shrinkage stress when compared to others. Depth of cure was 3 mm for composite containing 1% CQ and 2 mm for the other tested composites. Degree of conversion was inversely correlated with softening rate and directly correlated with elastic modulus and shrinkage stress. In conclusion, CQ concentration affects polymerization characteristics and mechanical strength of composites. The concentration of CQ in flowable composite for optimized polymerization and properties was 1% wt of the resin matrix, which allows adequate balance among degree of conversion, depth of cure, mechanical properties, and color characteristics of these materials.
Context: 'Carnauba' wax is a natural product obtained from the processing of the powder exuded from Copernicia prunifera (Miller) H. E. Moore (Arecaceae). This material is widely used in the Brazilian folk medicine, including the treatment of rheumatism and syphilis. Objective: To investigate the antiprotozoal activity of hexane and EtOH extracts from the 'carnauba' wax as well as from the isolated compounds from the bioactive extracts. Material and methods: Two different samples of 'carnauba' (C. prunifera) waxes -types 1 and 4 -were individually extracted using hexane (EH) and EtOH (EE). Aliquots of hexane (type 1 -EH-1 and EH-4) and EtOH (type 4 -EE-1 and EE-4) extracts were tested against promastigote (2-200 lg/mL in DMSO during 48 h at 24 C) and amastigote (3-150 lg/mL in DMSO during 120 h at 37 C) forms of Leishmania infantum as well as against trypomastigote (3-150 lg/mL in DMSO during 24 h at 37 C) forms of Trypanosoma cruzi. Bioactive extracts EH-1 and EE-4 were subjected to a bioactivity-guided fractionation to afford three dammarane-type triterpenoids (1-3). The in vitro antiprotozoal activities of the obtained compounds were evaluated as described above. Additionally, the cytotoxicity activity of compounds 1-3 against mammalian conjunctive cells (NCTC -2-200 lg/mL in DMSO during 48 h at 37 C) was determined. Results: From the bioactive hexane and EtOH extracts from the 'carnauba' (C. prunifera) wax, were isolated three dammarane-type triterpenoids: (24R Ã )-methyldammar-25-ene-3b,20-diol (carnaubadiol, 1), (24R Ã )-methyldammara-20,25-dien-3-one (2) and (24R Ã )-methyldammara-20,25-dien-3a-ol (3). These compounds were identified based on the analysis of NMR and MS spectroscopic data. Compounds 1-3 were effective against the intracellular amastigotes of L. infantum, with IC 50 values ranging from 8 to 52 lM, while compounds 1 and 3 displayed activity against trypomastigote forms of T. cruzi with IC 50 values of 15 and 35 lM, respectively. The mammalian cytotoxicity assay demonstrated no damage to NCTC conjunctive cells up to 200 lM, except for compound 1, which demonstrated a CC 50 value of 34 lM. Conclusion: Based on the results, it was possible to conclude that the detected antiprotozoal bioactivity of 'carnauba' (C. prunifera) wax extracts could be related to the presence of the natural dammarane triterpenoid derivatives. The results suggested that these compounds could be used as promising scaffolds for drug design studies for leishmaniasis and Chagas disease. ARTICLE HISTORY
The coordination of metal ions with flavonoids is applied to improve its pharmacological properties. To evaluate the role of ions on diosmin new complexes with Fe(II), Cu(II) and Co(II) ions were synthetized and characterized by UV, FT-IR and XRD techniques and surface morphology by SEM. The biological activity of coordination complexes in vitro, the antioxidant (ABTS), antibacterial (disc diffusion and MIC) and antitumoral activities (MTT) were analyzed. Diosmin when reacting with Fe(II) at 50ºC loses the sugar molecule becoming diosmetin (D) coordinated at 1D:1Fe ratio. In presence of Cu(II) and Co(II) at the same conditions besides losing the sugar, diosmin loses the methyl group at C4’ and H at C3’, producing a new ligand and complexes at 1D:2Cu or Co ratio, to produce DCu and DCo, respectively. The coordination of Cu and Fe improve the antioxidant activity of diosmin. DCo was the only presented antibacterial activity. Additionally, a specific antitumor effect of diosmin and metal complexes upon human leukemia cells was demonstrated, suggesting an immune regulatory action. The anti-melanoma activity of DCo is 10 times better than diosmin. Metal coordination could be used to improve drug activity and to give direction to a new possibility of clinical use for diosmin.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.