Browsing by Author "Moncada-Basualto, Mauricio"

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    Assessment of the Activity of Nitroisoxazole Derivatives against Trypanosoma cruzi
    (2024) Moncada-Basualto, Mauricio; Saavedra-Olavarria, Jorge; Rivero-Jerez, Paula S.; Rojas, Cristian; Maya, Juan D.; Liempi, Ana; Zuniga-Bustos, Matias; Olea-Azar, Claudio; Lapier, Michel; Perez, Edwin G.; Pozo-Martinez, Josue
    The development of new compounds to treat Chagas disease is imperative due to the adverse effects of current drugs and their low efficacy in the chronic phase. This study aims to investigate nitroisoxazole derivatives that produce oxidative stress while modifying the compounds' lipophilicity, affecting their ability to fight trypanosomes. The results indicate that these compounds are more effective against the epimastigote form of T. cruzi, with a 52 +/- 4% trypanocidal effect for compound 9. However, they are less effective against the trypomastigote form, with a 15 +/- 3% trypanocidal effect. Additionally, compound 11 interacts with a higher number of amino acid residues within the active site of the enzyme cruzipain. Furthermore, it was also found that the presence of a nitro group allows for the generation of free radicals; likewise, the large size of the compound enables increased interaction with aminoacidic residues in the active site of cruzipain, contributing to trypanocidal activity. This activity depends on the size and lipophilicity of the compounds. The study recommends exploring new compounds based on the nitroisoxazole skeleton, with larger substituents and lipophilicity to enhance their trypanocidal activity.
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    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.
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    Organometallic N-acylhydrazones of 5-nitrofuran and 5-nitrothiophene based: Synthesis, electrochemical, antiparasitic evaluation, and computational study
    (2023) Saldias, Marianela; Acuna, Alejandra; Mellado, Marco; Wilkinson, Shane R.; Moncada-Basualto, Mauricio; Artigas, Vania; Fuentealba, Mauricio; Lucero, Andrea; Oyarzo, Juan; Toro, Patricia M.
    In searching for new therapeutic agents for treating American trypanosomiasis and Human African trypanosomiasis, four nitroheterocyclic acylhydrazones of general formulae [R1-CH=N-NH-C(O)-(5-C4H2X)] (where R1 = ferrocenyl or cyrhetrenyl, and X = O or S) have been synthesized and characterized by spectroscopic techniques. Comparative studies of their stability by 1H-NMR and UV-Vis experiments were reported. Single-crystal X-ray diffraction confirmed the molecular structures of NF-1 and NT-2. Their X-ray crystal structures reveal that both adopt an E-configuration on the C=N moiety. Regarding the -NH-C(O)- bond, the structure of NF-1 confirmed a trans conformation, while NT-2 exhibited a cis-amide conformation. The cyclic voltammetry and electron spin resonance (ESR) experiments were conducted to study the electrochemical behavior of N-acylhydrazones. The antiparasitic activities of compounds against Trypanosoma cruzi (epimastigotes) and Trypanosoma brucei (trypomastigotes) revealed that cyrhetrenyl complexes were more effective than their ferrocenyl analogs. The cyrhetrenyl derivative NT-2 (EC50 = 2.25 mu M) showed activity against T. brucei comparable to the standard drug nifurtimox (Nfx, EC50 = 3.56 mu M). The ferrocenyl compound NT-1 (>200 mu M) was at least two times less cytotoxic than the Nfx (88.7 mu M) against the L-6 rat skeletal myoblast cell line and exhibited a selectivity like Nfx toward T. brucei. Density functional theory (DFT) calculations were utilized as an approximation to explain the impact of organometallic and heterocyclic rings on antiparasitic activities. This study supported the experimental results, confirming that the cyrhetrenyl fragment in N-acylhydrazone derivatives plays a significant role in the antitrypanosomal activity, which can be attributed to an increase in positive charge on the metal.
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    Polyphenolic Composition and Antioxidant Activity (ORAC, EPR and Cellular) of Different Extracts of Argylia radiata Vitroplants and Natural Roots
    (2022) Giordano, Ady; Morales-Tapia, Pablo; Moncada-Basualto, Mauricio; Pozo-Martinez, Josue; Olea-Azar, Claudio; Nesic, Aleksandra; Cabrera-Barjas, Gustavo
    Plant biochemistry studies have increased in recent years due to their potential to improve human health. Argylia radiata is an extremophile plant with an interesting polyphenolic profile. However, its biomass is scarce and occasionally available. Argylia in vitro biomass was obtained from tissue culture and compared with in vivo roots regarding its polyphenolic and flavonoid content. Different solvents were used to prepare extracts from the in vitro tissue of callus and aerial plant organs and in vivo roots. UPLC-MS/MS was used to assess the chemical composition of each extract. ORAC-FL and scavenging of free radicals (DPPH and OH) methods were used to determine the antioxidant capacity of extracts. Furthermore, the biological activity of the extracts was established using the cellular antioxidant activity method. The vitroplants were a good source of polyphenols (25-68 mg GAE/100 g tissue FW), and methanol was the most efficient solvent. Eight polyphenolic compounds were identified, and their antioxidant properties were investigated by different chemical methods with EPR demonstrating its specific scavenging activity against free radicals. All extracts showed cellular dose-dependent antioxidant activity. The methanolic extract of vitroplants showed the highest cellular antioxidant activity (44.6% and 51%) at 1 and 10 mu g/mL of extract, respectively. Vitroplants of A. radiata are proposed as a biotechnological product as a source of antioxidant compounds with multiple applications.