Browsing by Author "Bravo-Arrepol, Gaston"

Now showing 1 - 7 of 7
  • No Thumbnail Available
    Item
    Condensed tannins from Pinus radiata bark: Extraction and their nanoparticles preparation in water by green method
    (2024) Cabrera-Barjas, Gustavo; Butto-Miranda, Nicole; Nesic, Aleksandra; Moncada-Basualto, Mauricio; Segura, Rodrigo; Bravo-Arrepol, Gaston; Escobar-Avello, Danilo; Moeini, Arash; Riquelme, Sebastian; Neira-Carrillo, Andronico
    This work reports for the first time the production of condensed tannin nanoparticles stable in water via modification with glycine betaine. Pine bark, as a byproduct from the paper industry, was used as a source of condensed tannins of high molecular weight. Different glycine betaine concentrations were tested to produce condensed tannin nanoparticles, and the obtained nanoparticles were subjected to several characterization techniques (Dynamic Light Scattering, Field emission scanning electron microscopy, Zeta potential, Fourier transform infrared spectroscopy-Attenuated total reflectance, thermogravimetric analysis). The results showed that the highest stability possessed nanoparticles with 40 wt% glycine betaine. The average particle size distribution evaluated by scanning microscopy was 124 nm. Besides, the glycine betaine-modified condensed tannin nanoparticles demonstrated higher thermal stability with the starting degradation temperature at 238 degrees C. Finally, obtained nanoparticles showed an antioxidant capacity of 34,209 +/- 2194 mu mol ET/100 g and low cytotoxicity towards healthy human cells, representing the high potential to be used as a carrier of active compounds in agriculture, food, drug and medical sector.
  • No Thumbnail Available
    Item
    Effect of cellulose nanofibrils on vancomycin drug release from chitosan nanocomposite films
    (2023) Cabrera-Barjas, Gustavo; Becheran, Liliam; Valdes, Oscar; Giordano, Ady; Segura-del Rio, Rodrigo; Bravo-Arrepol, Gaston; Duran-Lara, Esteban F.; Cea, Juan; Berg, Alex; Castanos, Johana; Rodriguez-Llamazares, Saddys; Fuentes, Gaston; Katsarov, Plamen; Lukova, Paolina; Delattre, Cedric
    Overuse of antibiotic drugs usually leads to the further development of resistance to targeted bacteria. In this context, a controlled release system could be a solution to achieve higher drug efficiency without overdosing and drug resistance. In this work, nanocomposite films based on chitosan (CHI) reinforced with cellulose nanofibrils (CNF) for antibiotic release were prepared and characterized. Several nanocomposite films containing vancomycin hydrochloride and different amounts of CNF (5, 10, and 20 wt%) were prepared by the solvent casting method. Spectroscopic (FTIR), thermal (TG), morphological (SEM), mechanical, and swelling analyses of the films were performed to study the effect of nanofibers content on the nanocomposite properties. A good dispersion of CNF and the model drug was observed in the CHI matrix. FTIR spectroscopy confirmed the interaction between the film components (CNF and CHI). Film swelling capacity decreased with an increase of CNF content in the film formulation, whereas stiffness and tensile strength of the film increased. In addition, vancomycin release at pH = 7.4 was studied, and it was observed that controlled slower release could be achieved by tuning the CNF content in the chitosan film. The results confirm that these films could be useful for pharmaceutical purposes where the controlled release of drugs is required.
  • Thumbnail Image
    Item
    Extracted Eucalyptus globulus Bark Fiber as a Potential Substrate for Pinus radiata and Quillaja saponaria Germination
    (2024) Ferrer-Villasmil, Victor; Fuentealba, Cecilia; Reyes-Contreras, Pablo; Rubilar, Rafael; Cabrera-Barjas, Gustavo; Bravo-Arrepol, Gaston; Escobar-Avello, Danilo
    This study aimed to explore alternative substrates for growing forest species using eucalyptus bark. It evaluated the potential of extracted Eucalyptus globulus fiber bark as a substitute for commercial growing media such as coconut fiber, moss, peat, and compost pine. We determined the physicochemical parameters of the growing media, the germination rate, and the mean fresh and dry weights of seedlings. We used the Munoo-Liisa Vitality Index (MLVI) test to evaluate the phytotoxicity of the bark alone and when mixed with commercial substrates. Generally, the best mixture for seed growth was 75% extracted eucalyptus bark fiber and 25% commercial substrates. In particular, the 75E-25P (peat) mixture is a promising substitute for seedling growth of Pinus radiata, achieving up to 3-times higher MLVI than the control peat alone. For Quillaja saponaria, the best growth substrate was the 50E-50C (coconut fiber) mixture, which had the most significant MLVI values (127%). We added chitosan and alginate-encapsulated fulvic acid phytostimulants to improve the performance of the substrate mixtures. The fulvic acid, encapsulated or not, significantly improved MLVI values in Q. saponaria species and P. radiata in concentrations between 0.05 and 0.1% w/v. This study suggests that mixtures with higher levels of extracted fiber are suitable for growing forest species, thus promoting the application of circular economy principles in forestry.
  • No Thumbnail Available
    Item
    Influence of chitin nanofibers and gallic acid on physical-chemical and biological performances of chitosan-based films
    (2024) Cabrera-Barjas, Gustavo; Albornoz, Karin; Belchi, Maria Dolores Lopez; Giordano, Ady; Bravo-Arrepol, Gaston; Moya-Elizondo, Ernesto; San Martin, Juan; Valdes, Oscar; Nesic, Aleksandra
    In this work, chitosan films loaded with gallic acid and different content of chitin nanofibers were prepared and subjected to different characterization techniques. The results showed that the inclusion of gallic acid to chitosan films caused moderate decrease in water vapor permeability (by 29 %) and increased tensile strength of films (by 169 %) in comparison to the neat chitosan films. Furthermore, it was found that the addition of chitin nanofibers up to 30 % into chitosan/gallic acid films additionally improved tensile strength (by 474 %) and reduced plasticity of films (by 171 %), when compared to the chitosan/gallic acid films. Increased concentration of chitin nanofibers in films reduced the overall water vapor permeability of films by 51 %. In addition, gallic acid and chitin nanofibers had synergic effect on high chitosan film's antioxidant and antifungal activity toward Botrytis cinerea (both above 95 %). Finally, chitosan/gallic acid/chitin nanofibers films reduced decay incidence of strawberries, increased total soluble solid content, and promoted high production of some polyphenols during cold storage, in comparison to the control chitosan films and uncoated strawberry samples. Hence, these results suggest that chitosan/gallic acid/chitin nanofibers can present eco-sustainable approach for preservation of strawberries, giving them additional nutritional value.
  • No Thumbnail Available
    Item
    ISOLATED LIGNANS OF ARAUCARIA ARAUCANA (MOLINA) K. KOCH PROVIDE WOOD PROTECTION AGAINST ATTACK BY THE XYLOPHAGOUS FUNGUS PLEUROTUS OSTREATUS (JACQ.) P. KUMM
    (2023) Bravo-Arrepol, Gaston; Torres, Solange; Perez, Claudia; Gonzalez-Ramirez, Mariela; Figueroa, Fabian; Cabrera-Barjas, Gustavo; Aranda, Mario; Tiezzi, Antonio; Gavin, Jose; Paz, Cristian; Becerra, Jose
    Araucaria araucana (Molina) K. Koch is an evergreen conifer endemic of Southern Chile and it is considered a sacred tree by the Pehuenche originary people. A. araucana is endangered in the red book. The knots wood of A. araucana are resistant to biological degradation, due to producing a high amount of lignans, even after the decomposition of the tree is possible to find its knots in the forest. In the present study the chemical composition of three wood tissue of A. araucana; knotwood, stemwood, and branches were analyzed by HPTLC-MS, GC-MS, and NMR. Three lignans were purified and identified as eudesmin (1), ((1S,2R,3R) 1,2,3,4tetrahydrona phthalene-2,3-diyl) dimethanol (2) and secoisolarisiresinol (3). Folin-Ciocalteu, DPPH and resistance to biodegradation assays were evaluated to extracts from compressed wood zones. Eudesmin was identified as the principal lignan in knots with a 0.5%w/w and outperformed the fungicide Nipacide (R) P511 in protecting wood against xylophage fungi Pleurotus ostreatus (Jacq.) P. Kumm.
  • No Thumbnail Available
    Item
    Pretreated Eucalyptus globulus and Pinus radiata Barks: Potential Substrates to Improve Seed Germination for a Sustainable Horticulture
    (2023) Escobar-Avello, Danilo; Ferrer, Victor; Bravo-Arrepol, Gaston; Reyes-Contreras, Pablo; Elissetche, Juan P.; Santos, Jorge; Fuentealba, Cecilia; Cabrera-Barjas, Gustavo
    Commercial forest plantations in Chile are dominated by pine (Pinus radiata) and eucalyptus (Eucalyptus globulus). Tree bark is the main by-product of the forestry industry and has low value, but great potential for use as an agricultural substrate. However, the direct use of bark fibers may cause plant phytotoxicity due to the presence of polyphenolic and other compounds. This study aims to evaluate the physicochemical properties of E. globulus and P. radiata bark after water extraction treatments. The phytotoxicity of the resulting extracted bark alone and that mixed with commercial substrates (coconut fiber, moss, peat, and composted pine) at different ratios (25 to 75 wt%) were assessed using the Munoo-Liisa vitality index (MLVI) test. For all treatments, the seed germination and growth of radish (Raphanus sativus) and Chinese cabbage (Brassica rapa) species were evaluated and compared to a commercial growing medium (peat) as a control. The optimal mixture for seed growth was determined to be 75% extracted E. globulus bark fiber and 25% commercial substrates such as peat (P), coconut fiber (C), moss (M), and composted pine (CP), as indicated by the MLVI and germination results. Two phytostimulant products, chitosan and alginate-encapsulated fulvic acid, were added to the best substrate mixture, with the purpose of improving their performance. Encapsulated fulvic acid at 0.1% w/v was effective in promoting plant growth, while chitosan at all of the concentrations studied was effective only for mixture 75E-25CP. The mixture of E. globulus fiber and commercial substrates, containing a high proportion of water-extracted fiber (75%), shows the potential to be used in the growth of horticultural crops and in the plant nursery industry.
  • No Thumbnail Available
    Item
    Sulfated Polysaccharide Extracted from the Green Algae Codium bernabei: Physicochemical Characterization and Antioxidant, Anticoagulant and Antitumor Activity
    (2022) Figueroa, Fabian A.; Abdala-Diaz, Roberto T.; Perez, Claudia; Casas-Arrojo, Virginia; Nesic, Aleksandra; Tapia, Cecilia; Duran, Carla; Valdes, Oscar; Parra, Carolina; Bravo-Arrepol, Gaston; Soto, Luis; Becerra, Jose; Cabrera-Barjas, Gustavo
    Codium bernabei is a green alga that grows on Chilean coasts. The composition of its structural polysaccharides is still unknown. Hence, the aim of this work is to isolate and characterize the hot water extracted polysaccharide fractions. For this purpose, the water extracts were further precipitated in alcohol (TPs) and acid media (APs), respectively. Both fractions were characterized using different physicochemical techniques such as GC-MS, GPC, FTIR, TGA, and SEM. It is confirmed that the extracted fractions are mainly made of sulfated galactan unit, with a degree of sulfation of 19.3% (TPs) and 17.4% (ATs) and a protein content of 3.5% in APs and 15.6% in TPs. Other neutral sugars such as xylose, glucose, galactose, fucose, mannose, and arabinose were found in a molar ratio (0.05:0.6:1.0:0.02:0.14:0.11) for TPs and (0.05:0.31:1.0:0.03:0.1:0.13) for ATs. The molecular weight of the polysaccharide samples was lower than 20 kDa. Both polysaccharides were thermally stable (Tonset > 190 degrees C) and showed antioxidant activity according to the ABTS(center dot+) and DPPH tests, where TPs fractions had higher scavenging activity (35%) compared to the APs fractions. The PT and APTTS assays were used to measure the anticoagulant activity of the polysaccharide fractions. In general, the PT activity of the TPs and APs was not different from normal plasma values. The exception was the TPs treatment at 1000 mu g mL(-1) concentration. The APTTS test revealed that clotting time for both polysaccharides was prolonged regarding normal values at 1000 mu g mL(-1). Finally, the antitumor test in colorectal carcinoma (HTC-116) cell line, breast cancer (MCF-7) and human leukemia (HL-60) cell lines showed the cytotoxic effect of TPs and APs. Those results suggest the potential biotechnological application of sulfate galactan polysaccharides isolated from a Chilean marine resource.