RESUMO
Chicha gum is a natural polymer obtained from the Sterculia striata plant. The hydroxyl groups of its structure have a chemical affinity to form hydrogels, which favors the association with biologically active molecules, such as nerolidol. This association improves the biological properties and allows the material to be used in drug delivery systems. Chicha gum hydrogels associated with nerolidol were produced at two concentrations: 0.01 and 0.02 g mL-1. Then, the hydrogels were characterized by thermogravimetry (TG), Fourier Transform Infrared spectroscopy (FTIR), and rheological analysis. The antibacterial activity was tested against Staphylococcus aureus and Escherichia coli. The cytotoxicity was evaluated against Artemia salina. Finally, an in vivo healing assay was carried out. The infrared characterization indicated that interactions were formed during the gel reticulation. This implies the presence of nerolidol in the regions at 3100-3550 cm-1. The rheological properties changed with an increasing concentration of nerolidol, which resulted in less viscous materials. An antibacterial 83.6% growth inhibition effect was observed using the hydrogel with 0.02 g mL-1 nerolidol. The in vivo healing assay showed the practical activity of the hydrogels in the wound treatment, as the materials promoted efficient re-epithelialization. Therefore, it was concluded that the chicha hydrogels have the potential to be used as wound-healing products.
Assuntos
Sesquiterpenos , Sterculia , Sterculia/química , Hidrogéis/química , Antibacterianos/química , Espectroscopia de Infravermelho com Transformada de FourierRESUMO
Cryogels are novel materials because the manufacturing process known as cryostructuring allows biopolymers to change their properties as a result of repeated controlled freeze-thaw cycles. Hydrogels of xanthan and karaya gums were evaluated after undergoing up to four controlled freeze-thaw cycles in indirect contact with liquid nitrogen (up to -150 °C) to form cryogels. Changes in structural, molecular, rheological, and thermal properties were evaluated and compared to those of their respective hydrogels. Samples were also analyzed by Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy with Attenuated Total Reflection (FTIR-ATR), Rotational Rheology (RR), Modulated Differential Scanning Calorimetry (MDSC) and zeta potential (ζ). In general, significant differences (p < 0.05) between the numbers of freeze-thaw cycles were found. Karaya cryogels were not stable to repeated cycles of cryostructuring such as the three-cycle xanthan cryogel, which has the best structural order (95.55%), molecular interactions, and thermal stability, which allows the generation of a novel material with improved thermal and structural properties that can be used as an alternative in food preservation.
Assuntos
Criogéis/química , Tecnologia de Alimentos/métodos , Hidrogéis/química , Polissacarídeos Bacterianos/química , Sterculia/química , Biofilmes , Varredura Diferencial de Calorimetria , Congelamento , Temperatura Alta , Microscopia Eletrônica de Varredura , Polímeros/química , Álcool de Polivinil/química , Reologia , Espectroscopia de Infravermelho com Transformada de Fourier , XanthomonasRESUMO
The objective of this research was to modify chicha gum with phthalic anhydride to obtain a new biologically active material. The chemical modification of the gum structure was proven through FTIR, elemental analysis, XRD, TG, and DSC. The derived materials demonstrated excellent inhibitory effect against P. aeruginosa and K. pneumoniae species (rating 100% inhibition) and could also inhibit Escherichia coli growth. The best antimicrobial activity observed for the derivatives suggests that chicha gum hydrophobization due to the addition of phthalic groups improved the interaction of these derivatives with bacterial cell wall components. On the other hand, the derivatives increased CC50 in macrophages but did not present acute toxicity or hemolytic activity, indicating that they are promising for use in prophylaxis or treatment of infections caused by Gram-negative bacteria.
Assuntos
Antibacterianos/farmacologia , Bactérias Gram-Negativas/efeitos dos fármacos , Macrófagos/efeitos dos fármacos , Anidridos Ftálicos/química , Gomas Vegetais/química , Sterculia/química , Animais , Sobrevivência Celular , Esterificação , Feminino , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Testes de Sensibilidade MicrobianaRESUMO
Natural polysaccharides have been investigated as vehicles for oral insulin administration. Because of their non-toxic, renewable, low cost and readily available properties, gums find multiple applications in the pharmaceutical industry. This work aimed to develop a Sterculia striata gum-based formulation associated with additional biopolymers (dextran sulfate, chitosan, and albumin), a crosslinking agent (calcium chloride) and stabilizing agents (polyethylene glycol and poloxamer 188), to increase the oral bioavailability of proteins. Insulin was used as a model drug and the methods used to prepare the formulation were based on ionotropic pregelation followed by electrolytic complexation of oppositely charged biopolymers under controlled pH conditions. The developed formulation was characterized to validate its efficacy, by the determination of its average particle size (622 nm), the insulin encapsulation efficiency (70%), stability in storage for 30 days, and the in vitro mucoadhesion strength (92.46 mN). Additionally, the developed formulation preserved about 64% of initial insulin dose in a simulated gastric medium. This study proposed, for the first time, a Sterculia striata gum-based insulin delivery system with potential for the oral administration of protein drugs, being considered a valid alternative for efficient delivery of those drugs.
Assuntos
Goma de Karaya/química , Preparações Farmacêuticas/química , Proteínas/química , Sterculia/química , Administração Oral , Disponibilidade Biológica , Biopolímeros/química , Cloreto de Cálcio/química , Portadores de Fármacos/química , Sistemas de Liberação de Medicamentos/métodos , Liberação Controlada de Fármacos , Insulina/química , Tamanho da Partícula , Poloxâmero/química , Polietilenoglicóis/químicaRESUMO
It was developed a material to act as an antimicrobial and antiparasitic agent through a modification reaction in the gum structure extracted from the plant Sterculia striata. This material was characterized, the oxidant activity was evaluated and the antimicrobial activity against Candida albicans, Escherichia coli, Pseudomonas aeruginosa, Salmonella Typhimurium and Klebsiella pneumoniae was investigated, in addition to the effect against Leishmania amazonensis, testing its acute toxicity and its cytotoxicity in human cells. Characterization techniques proved the success of chemical modification. The modification led to an increase in antioxidant activity, with excellent antibacterial activity, reaching almost 100% inhibition for P. aeruginosa and S. Typhimurium, and inhibitory effect above 70% against L. amazonensis, with an affinity far superior to the parasite than macrophages. The derivative showed no acute toxicity, it was non-hemolytic, increased cell viability in macrophages and fibroblasts, and stimulated cell proliferation of keratinocytes, thus being a strong candidate to be used as an antimicrobial and antiparasitic agent in biomedical applications.
Assuntos
Anti-Helmínticos/síntese química , Anti-Infecciosos/síntese química , Gomas Vegetais/química , Sterculia/química , Ácido Acético/química , Animais , Anti-Helmínticos/toxicidade , Anti-Infecciosos/toxicidade , Candida/efeitos dos fármacos , Células Cultivadas , Feminino , Fibroblastos/efeitos dos fármacos , Leishmania/efeitos dos fármacos , Macrófagos/efeitos dos fármacos , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Salmonella typhimurium/efeitos dos fármacos , OvinosRESUMO
This work was aimed at the production and characterization of a new nanocarrier based on a Sterculia striata polysaccharide (SSP) modified via acylation reaction with propionic anhydride. Nanocapsules of propionated SSP (PSSP) were produced via spontaneous nanoemulsification process and tested as a potential amphotericin B (AMB) nanocarrier. Stable nanoparticles with a very low polydispersity index (0.08-0.29) and high zeta potential (ζ -42.7 to -53.8 mV) were obtained. Particle size was dependent on the degree of substitution and ranged from 205 to 286 nm. A nanocapsule with a degree of substitution (DS) of 2.53 (NCP 2.53) was selected for encapsulation, biocompatibility, and antifungal evaluation against Candida albicans strains. A maximum of 98.3% AMB encapsulation was achieved. Encapsulated AMB was in its monomeric form and showed good biocompatibility and antifungal activity against four C. albicans strains. Data indicate that PSSP has potential as a nanocarrier system for AMB.
Assuntos
Anfotericina B/farmacologia , Portadores de Fármacos/química , Nanopartículas/química , Polissacarídeos/química , Propionatos/química , Sterculia/química , Antifúngicos/farmacologia , Materiais Biocompatíveis/química , Candida albicans/efeitos dos fármacos , Liberação Controlada de Fármacos , Hemólise/efeitos dos fármacos , Humanos , Testes de Sensibilidade Microbiana , Nanocápsulas/química , Tamanho da Partícula , Espectrofotometria Ultravioleta , Espectroscopia de Infravermelho com Transformada de FourierRESUMO
Stable oil nanocapsules based on acetylated Sterculia striata polysaccharide (ASSP) were produced without the use of a surfactant, and derivatives of ASSP with four different degrees of substitution (DS) were synthesised. The data revealed that only derivatives with high DS were able to produce nanocapsules (NC), which exhibited monomodal size distribution profiles with a Z-average particle size, ζ-potential, and polydispersity index (PDI) that were dependent on ASSP DS and concentration. Nanocapsules were loaded with amphotericin B (AMB) with encapsulation efficiencies (EE%) that were dependent on drug and ASSP concentrations and DS. A maximum EE% value of 99.2% was achieved, and the loaded AMB was found to be in a monomeric form, even with a concentration one hundredfold higher than that usually observed for commercial AMB aqueous solutions. Loaded nanocapsules show an in vitro controlled release of AMB. As the monomeric AMB state decreased drug toxicity, ASSP nanocapsules loaded with AMB (NC1.68) have potential for use as a drug delivery system. AMB loaded NC 1.68 keeps its activity against 5 strains of Candida albicans tested.
Assuntos
Anfotericina B/administração & dosagem , Antifúngicos/administração & dosagem , Nanocápsulas/química , Polissacarídeos/química , Sterculia/química , Acetilação , Materiais Biocompatíveis , Portadores de Fármacos/química , Sistemas de Liberação de Medicamentos , Liberação Controlada de Fármacos , Humanos , Teste de Materiais , Testes de Sensibilidade Microbiana , Microscopia de Força Atômica , Análise EspectralRESUMO
The Sterculia striata nut commonly known as chichá is consumed raw or toasted inBrazil but information on its chemical composition and antioxidant activity are scarce in the literature. In this work, the nutritional composition, minerals profile, lipid composition and phenolic compounds profile of chichá nuts and its by-products (pellicle and shell) were determined. The results showed that the nuts and the cake contain considerable amount of fibers and proteins and are rich in minerals (Fe, Mn and Cu). Oleic acid was the main fatty acid (37.8%), and PPO (36.0%) and POP (15.6%) were the main triacylglycerides present in the chichá oil. The phytosterols ß-sitosterol, stigmasteroland campesterol (1848.5µgg-1, 542.2µgg-1 and 186.3µgg-1, respectively), and the γ-, δ-, α- and ß-tocopherol (8.85; 2.10; 1.64, and 0.11mg100g-1, respectively) were identified in the oil. The antioxidant activity (ABTS and FRAP assays) followed the order pellicle>shell>nuts (13.25 and 84.65; 8.71 and 64.3; 5.85 and 36.79µmolTEACg-1, respectively). The main phenolic compounds identified in the extracts were ellagic and ferulic acids; ellagic and protocatechuic acids; and protocatechuic, ellagic and methoxyphenylacetic acids for the nuts, shells and pellicle, respectively. A strong positive correlation was observed between total phenolic content and antioxidant activity determined by ABTS and FRAP assays (r=0.9067, p<0.01; and r=0.9584, p<0.01; respectively). Collectively, the results showed that the chichá is a nut of high nutritional value, rich in bioactive compounds.
Assuntos
Antioxidantes/análise , Análise de Alimentos/métodos , Lipídeos/análise , Minerais/análise , Valor Nutritivo , Nozes/química , Fenóis/análise , Sterculia/químicaRESUMO
Sterculia apetala (order: Malvales, family: Sterculiaceae) seed oil contains two cyclopropene fatty acids: sterculic and malvalic acid. Both positive and negative effects have been associated with the consumption of sterculic oil. In Mexico, S. apetala seeds are consumed after being boiled or roasted, used as chocolate flavoring, and utilized as animal fodder. Therefore, it is important to evaluate whether the consumption of this seed has a negative impact on the organism. The aim of this study was to evaluate the effect of administration of sterculic oil, during an 8-week period, on anxiety-like behavior and spontaneous locomotor activity in Zucker rats, analyzed through light/dark and open-field tests. The results showed that the consumption of sterculic oil decreased exploration latency in light/dark tests, which suggests an anxiolytic-like effect. Alterations in time spent on rearing and grooming were present in open-field tests, but this was not statistically significant, discarding nonspecific motor alterations. The alterations found in this study are possibly related to intrinsic obesity and metabolic complications present in the Zucker rat model, where leptin plays an important role in animal mood, more so than sterculic oil consumption.
Assuntos
Ansiolíticos/administração & dosagem , Ansiedade/tratamento farmacológico , Ansiedade/psicologia , Óleos de Plantas/administração & dosagem , Sterculia/química , Animais , Ansiolíticos/química , Ansiedade/etiologia , Comportamento Animal/efeitos dos fármacos , Humanos , Masculino , Obesidade/complicações , Obesidade/tratamento farmacológico , Obesidade/psicologia , Óleos de Plantas/química , Ratos , Ratos Zucker , Sementes/químicaRESUMO
The Sterculia striata ethanolic extract (Ss-EtOH) inhibited gastric lesions induced by ethanol, HCl/ethanol, and ischemia/reperfusion, but not those induced by indomethacin, and did not alter the gastric secretion. Ss-EtOH restored the catalase activity and content of nonprotein sulfhydryl groups in the stomach of mice treated with ethanol. The gastroprotection induced by Ss-EtOH in the ethanol-induced gastric lesion model was abolished by N(G)-nitroL-arginine methyl ester (L-NAME) pretreatment, suggesting the involvement of nitric oxide and antioxidant compounds, but not prostaglandins, in this activity. Lupeol obtained from Ss-EtOH promoted gastroprotection as well as the extract at the same dose, and it must therefore contribute to the observed effects.