RESUMO
BACKGROUND: Sunscald is a physiological disorder that occurs in many horticultural products when exposed to excessive solar radiation and high temperatures. Traditionally, sunscald is controlled using physical barriers that reflect radiation, however this practice is not always efficient. A possible alternative would be the use of chemical barriers, such as mycosporine-like amino acids (MAAs), which protect aquatic organisms against ultraviolet (UV) radiation. Thus, this study aimed to develop a lipid-based emulsion containing MAAs for using in the preharvest of horticultural products. RESULTS: Emulsions were developed using 10% (w/v) of corn oil (CO) and soybean oil (SO), carnauba wax (CW), and beeswax (BW) as lipid bases (LBs). The emulsion containing CW and ammonium hydroxide was the most stable, resembling commercial wax. Therefore, this formulation was used as the basis for the incorporation of the commercial product Helioguard™ 365, a source of MAA, in concentrations of 0%, 1%, 2%, and 4% (v/v). The MAA incorporation resulted in little modifications in the stability of the emulsion, providing an increase in the absorbance with peaks in the UV-B ranging from 280 to 300 nm. CONCLUSION: The lipid-base emulsion containing MAAs could be used as a chemical barrier to control sunscald in horticultural products. © 2021 Society of Chemical Industry.
Assuntos
Aminoácidos/química , Aminoácidos/farmacologia , Cicloexanóis/química , Frutas/efeitos da radiação , Substâncias Protetoras/farmacologia , Verduras/efeitos da radiação , Cicloexanóis/farmacologia , Emulsões/química , Emulsões/farmacologia , Substâncias Protetoras/química , Protetores contra Radiação , Raios UltravioletaRESUMO
RATIONALE: Mycosporine-like amino acids (MAAs) are UV-absorbing compounds produced by fungi, algae, lichens, and cyanobacteria when exposed to UV radiation. These compounds have photoprotective and antioxidant functions and have been widely studied for possible use in sunscreens and anti-aging products. This study aims to identify MAA-producing cyanobacteria with potential application in cosmetics. METHODS: A method for the identification of MAAs was developed using ultrahigh-performance liquid chromatography with diode array detection coupled to quadrupole time-of-flight mass spectrometry (UHPLC-DAD/QTOFMS). Chromatographic separation was carried out using a Synergi 4 µ Hydro-RP 80A column (150 × 2,0 mm) at 30°C with 0.1% formic acid aqueous solution + 2 mM ammonium formate and acetonitrile/water (8:2) + 0.1% formic acid as a mobile phase. RESULTS: Out of the 69 cyanobacteria studied, 26 strains (37%) synthesized MAAs. Nine different MAAs were identified using UHPLC-DAD/QTOFMS. Iminomycosporines were the major group detected (7 in 9 MAAs). In terms of abundance, the most representative genera for MAA production were heterocyte-forming groups. Oscilatoria sp. CMMA 1600, of homocyte type, produced the greatest diversity of MAAs. CONCLUSIONS: The UHPLC-DAD/QTOFMS method is a powerful tool for identification and screening of MAAs in cyanobacterial strains as well as in other organisms such as dinoflagellates, macroalgae, and microalgae. The different cyanobacterial genera isolated from diverse Brazilian biomes and environments are prolific sources of MAAs.
Assuntos
Aminoácidos/análise , Aminoácidos/química , Cromatografia Líquida de Alta Pressão/métodos , Cianobactérias/química , Espectrometria de Massas/métodos , Brasil , Cianobactérias/metabolismo , Cicloexanóis/análise , Cicloexanóis/química , Cicloexanonas/análise , Cicloexanonas/química , Cicloexilaminas/análise , Cicloexilaminas/química , Glicina/análogos & derivados , Glicina/análise , Glicina/químicaRESUMO
Since the beginning of life on Earth, cyanobacteria have been exposed to natural ultraviolet-A radiation (UV-A, 315-400â¯nm) and ultraviolet-B radiation (UV-B, 280-315â¯nm), affecting their cells' biomolecules. These photoautotrophic organisms have needed to evolve to survive and thus, have developed different mechanisms against ultraviolet radiation. These mechanisms include UVR avoidance, DNA repair, and cell protection by producing photoprotective compounds like Scytonemin, carotenoids, and Mycosporine-like amino acids (MAAs). Lyngbya marine species are commercially important due to their secondary metabolites that show a range of biological activities including antibacterial, insecticidal, anticancer, antifungal, and enzyme inhibitor. The main topic in this review covers the Lyngbya sp., a cyanobacteria genus that presents photoprotection provided by the UV-absorbing/screening compounds such as MAAs and Scytonemin. These compounds have considerable potentialities to be used in the cosmeceutical, pharmaceutical, biotechnological and biomedical sectors and other related manufacturing industries with an additional value of environment friendly in nature. Scytonemin has UV protectant, anti-inflammatory, anti-proliferative, and antioxidant activity. MAAs act as sunscreens, provide additional protection as antioxidants, can be used as UV protectors, activators of cell proliferation, skin-care products, and even as photo-stabilizing additives in paints, plastics, and varnishes. The five MAAs identified so far in Lyngbya sp. are Asterina-330, M-312, Palythine, Porphyra-334, and Shinorine are capable of dissipating absorbed radiation as harmless heat without producing reactive oxygen species.
Assuntos
Aminoácidos/química , Cianobactérias/metabolismo , Cicloexanóis/química , Indóis/química , Fenóis/química , Protetores Solares/química , Raios Ultravioleta , Aminoácidos/isolamento & purificação , Antioxidantes/química , Cicloexanóis/isolamento & purificação , Indóis/isolamento & purificação , Fenóis/isolamento & purificação , Protetores Solares/metabolismoRESUMO
The sustainable transformation of basic chemicals into organic compounds of industrial interest using mild oxidation processes has proved to be challenging. The production of cyclohexanol and cyclohexanone from cyclohexane is of interest to the nylon manufacturing industry. However, the industrial oxidation of cyclohexane is inefficient. Heterogeneous photocatalysis represents an alternative way to synthesize these products, but the optimization of this process is difficult. In this work, the yields of photocatalytic cyclohexane conversion using Degussa P-25 under visible light were optimized. To improve cyclohexanol production, acetonitrile was used as an inert photocatalytic solvent. Experiments showed that the use of the optimized conditions under solar light radiation did not affect the cyclohexanol/cyclohexanone ratio. In addition, the main radical intermediary produced in the reaction was detected by the electronic paramagnetic resonance technique.
Assuntos
Cicloexanóis/química , Cicloexanonas/química , Luz , Oxirredução/efeitos da radiação , Processos Fotoquímicos/efeitos da radiação , Acetonitrilas/química , Catálise , Espectroscopia de Ressonância de Spin Eletrônica , Cinética , Fotólise , Luz Solar , Titânio/químicaRESUMO
An efficient and facile general method for the synthesis of conduritol C analogs, taking advantage of an enantioselective biocatalysis process of monosubstituted benzenes, is described. The absolute stereochemical patterns of the target molecules (−)-conduritol C, (−)-bromo-conduritol C, and (−)-methyl-conduritol C were achieved by means of chemoenzymatic methods. The stereochemistry present at the homochiral cyclohexadiene-cis-1,2-diols derived from the arene biotransformation and the enantioselective ring opening of a non-isolated vinylepoxide derivative permitted the absolute configuration of the carbon bearing the hydroxyl groups at the target molecules to be established. All three conduritols and two intermediates were crystallized, and their structures were confirmed by X-ray diffraction. The three conduritols and intermediates were isostructural. The versatility of our methodology is noteworthy to expand the preparation of conduritol C analogs starting from toluene dioxygenase (TDO) monosubstituted arene substrates.
Assuntos
Cicloexanóis/síntese química , Cicloexenos/síntese química , Biocatálise , Biotransformação , Cristalografia por Raios X , Cicloexanóis/química , Cicloexenos/química , Modelos Moleculares , Estrutura Molecular , EstereoisomerismoRESUMO
This study evaluated the removal of filling material with ProTaper Universal Rotary Retreatment system (PTR) combined with solvents and the influence of solvents on the bond strength (PBS) of sealer to intraradicular dentin after canal reobturation. Roots were endodontically treated and distributed to five groups (n = 12). The control group was not retreated. In the four experimental groups, canals were retreated with PTR alone or in combination with xylol, orange oil, and eucalyptol. After filling material removal, two specimens of each group were analysed by SEM and µCT to verify the presence of filling remnants on root canal walls. The other roots were reobturated and sectioned in 1-mm-thick dentin slices that were subjected to the push-out test. Data were analysed by two-way ANOVA and Tukey's test (α = 0.05). SEM and µCT analysis revealed that all retreatment techniques left filling remnants on canal walls. The control group (3.47 ± 1.21) presented significantly higher (p < 0.05) PBS than the experimental groups. The groups retreated with PTR alone (2.59 ± 0.99) or combined with xylol (2.54 ± 0.77) and orange oil (2.32 ± 0.93) presented similar bond strength (p > 0.05), and differed significantly from the group with eucalyptol (1.89 ± 0.63). The solvents reduced the PBS of the sealer to dentin and no retreatment technique promoted complete removal of filling material.
Assuntos
Cavidade Pulpar/efeitos dos fármacos , Dentina/efeitos dos fármacos , Materiais Restauradores do Canal Radicular/química , Preparo de Canal Radicular/métodos , Solventes/química , Análise de Variância , Cicloexanóis/química , Colagem Dentária , Instrumentos Odontológicos , Resinas Epóxi/química , Eucaliptol , Guta-Percha , Humanos , Teste de Materiais , Microscopia Eletrônica de Varredura , Monoterpenos/química , Óleos de Plantas/química , Reprodutibilidade dos Testes , Retratamento/instrumentação , Preparo de Canal Radicular/instrumentaçãoRESUMO
Abstract This study evaluated the removal of filling material with ProTaper Universal Rotary Retreatment system (PTR) combined with solvents and the influence of solvents on the bond strength (PBS) of sealer to intraradicular dentin after canal reobturation. Roots were endodontically treated and distributed to five groups (n = 12). The control group was not retreated. In the four experimental groups, canals were retreated with PTR alone or in combination with xylol, orange oil, and eucalyptol. After filling material removal, two specimens of each group were analysed by SEM and µCT to verify the presence of filling remnants on root canal walls. The other roots were reobturated and sectioned in 1-mm-thick dentin slices that were subjected to the push-out test. Data were analysed by two-way ANOVA and Tukey’s test (α = 0.05). SEM and µCT analysis revealed that all retreatment techniques left filling remnants on canal walls. The control group (3.47 ± 1.21) presented significantly higher (p < 0.05) PBS than the experimental groups. The groups retreated with PTR alone (2.59 ± 0.99) or combined with xylol (2.54 ± 0.77) and orange oil (2.32 ± 0.93) presented similar bond strength (p > 0.05), and differed significantly from the group with eucalyptol (1.89 ± 0.63). The solvents reduced the PBS of the sealer to dentin and no retreatment technique promoted complete removal of filling material.
Assuntos
Humanos , Cavidade Pulpar/efeitos dos fármacos , Dentina/efeitos dos fármacos , Materiais Restauradores do Canal Radicular/química , Preparo de Canal Radicular/métodos , Solventes/química , Análise de Variância , Cicloexanóis/química , Colagem Dentária , Instrumentos Odontológicos , Resinas Epóxi/química , Guta-Percha , Teste de Materiais , Microscopia Eletrônica de Varredura , Monoterpenos/química , Óleos de Plantas/química , Reprodutibilidade dos Testes , Retratamento/instrumentação , Preparo de Canal Radicular/instrumentaçãoRESUMO
The aim of this study is to evaluate the solubility of a Mineral Trioxide Aggregate sealer (MTA-Fillapex) compared with five other sealers, calcium hydroxide (Sealapex), resin (Realseal), zinc oxide-eugenol (Tubli-Seal), and two epoxy resins (AH-26 and AH-Plus), in chloroform and eucalyptoil in static and ultrasonic environments. Samples of each sealer were prepared (n = 180) and then divided into 12 groups that were immersed in solvents for 5 and 10 min in static and ultrasonic environments. The mean weight loss was determined, and the values were compared using Student's t-test, One-way ANOVA, and Tukey's HSD post-hoc test (p < 0.05). In chloroform, MTA-Fillapex, AH-26, and Sealapex displayed moderate solubility with no significant difference in dissolution (p = 0.125); however, their dissolution was significantly lower than that of AH-Plus (p < 0.001), which was almost fully dissolved after 10 minutes. Realseal was significantly less soluble than all sealers (p < 0.001). In eucalyptoil, MTA-Fillapex showed low solubility, as all of the sealers did, but Tubli-Seal was significantly more soluble than other sealers (p < 0.001). Using ultrasonic activation resulted in a significantly higher dissolution rate in chloroform for all sealers except MTA-Fillapex after 10 min (p = 0.226). In eucalyptoil, ultrasonic activation significantly increased the dissolution rate of all sealers except MTA-Fillapex after 5 and 10 min, Sealapex at 10 min, and AH-Plus at 5 min (p > 0.05). In conclusion, MTA-Fillapex was not sufficiently dissolved in either solvent. Ultrasonic activation had limited effectiveness on MTA-Fillapex dissolution, whereas it significantly increased the efficiency of solvents in dissolving a number of endodontic sealers.
Assuntos
Compostos de Alumínio/química , Compostos de Cálcio/química , Clorofórmio/química , Cicloexanóis/química , Monoterpenos/química , Óxidos/química , Materiais Restauradores do Canal Radicular/química , Silicatos/química , Solventes/química , Análise de Variância , Bismuto/química , Hidróxido de Cálcio/química , Combinação de Medicamentos , Resinas Epóxi/química , Eucaliptol , Imersão , Teste de Materiais , Valores de Referência , Reprodutibilidade dos Testes , Salicilatos/química , Prata/química , Solubilidade , Fatores de Tempo , Titânio/química , Ondas Ultrassônicas , Cimento de Óxido de Zinco e Eugenol/químicaRESUMO
Abstract The aim of this study is to evaluate the solubility of a Mineral Trioxide Aggregate sealer (MTA-Fillapex) compared with five other sealers, calcium hydroxide (Sealapex), resin (Realseal), zinc oxide-eugenol (Tubli-Seal), and two epoxy resins (AH-26 and AH-Plus), in chloroform and eucalyptoil in static and ultrasonic environments. Samples of each sealer were prepared (n = 180) and then divided into 12 groups that were immersed in solvents for 5 and 10 min in static and ultrasonic environments. The mean weight loss was determined, and the values were compared using Student's t-test, One-way ANOVA, and Tukey's HSD post-hoc test (p < 0.05). In chloroform, MTA-Fillapex, AH-26, and Sealapex displayed moderate solubility with no significant difference in dissolution (p = 0.125); however, their dissolution was significantly lower than that of AH-Plus (p < 0.001), which was almost fully dissolved after 10 minutes. Realseal was significantly less soluble than all sealers (p < 0.001). In eucalyptoil, MTA-Fillapex showed low solubility, as all of the sealers did, but Tubli-Seal was significantly more soluble than other sealers (p < 0.001). Using ultrasonic activation resulted in a significantly higher dissolution rate in chloroform for all sealers except MTA-Fillapex after 10 min (p = 0.226). In eucalyptoil, ultrasonic activation significantly increased the dissolution rate of all sealers except MTA-Fillapex after 5 and 10 min, Sealapex at 10 min, and AH-Plus at 5 min (p > 0.05). In conclusion, MTA-Fillapex was not sufficiently dissolved in either solvent. Ultrasonic activation had limited effectiveness on MTA-Fillapex dissolution, whereas it significantly increased the efficiency of solvents in dissolving a number of endodontic sealers.
Assuntos
Óxidos/química , Materiais Restauradores do Canal Radicular/química , Solventes/química , Clorofórmio/química , Silicatos/química , Compostos de Cálcio/química , Compostos de Alumínio/química , Cicloexanóis/química , Monoterpenos/química , Valores de Referência , Prata/química , Solubilidade , Fatores de Tempo , Titânio/química , Cimento de Óxido de Zinco e Eugenol/química , Bismuto/química , Teste de Materiais , Hidróxido de Cálcio/química , Salicilatos/química , Reprodutibilidade dos Testes , Análise de Variância , Combinação de Medicamentos , Resinas Epóxi/química , Ondas Ultrassônicas , Eucaliptol , ImersãoRESUMO
A new approach to the study of the effects on human skin of mycosporine-like amino acids (MAAs) and gadusol (Gad) incorporated in polymer gel is proposed in this work. The depth profile and photoprotector effects of Pluronic F127® gels containing each of the natural actives were evaluated by in vivo confocal Raman spectroscopy aiming at the analysis of the biochemical changes on human skin. Hierarchical cluster analysis (HCA) showed that the data corresponding to different depths of the skin, from surface to 4 µm, and from 6 to 16 µm, remained in the same cluster. In vivo Raman spectra, classified into five different layers of epidermis according to their similarities, indicated that the amount of Gad gel increased by about 26% in the outermost layer of the stratum corneum (SC) and that MAAs gel at 2 µm depth was 103.4% higher than in the outermost layer of the SC. Variations in the SC of urocanic acid at 1490-1515 cm(-1) and 1652 cm(-1) and histidine at 1318 cm(-1) were calculated, before and after UV exposure with or without gels. With the application of gels the vibrational modes that correspond to lipids in trans conformation (1063 and 1128 cm(-1)) increased with respect to normal skin, whereas gauche conformation (1085 cm(-1)) disappeared. Our studies suggest that gels protected the skin against the stress of the natural defense mechanism caused by high levels of UV exposure.