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    Experimental and computational studies of Schiff bases derived from 4-aminoantipyrine as potential antibacterial and anticancer agents
    (Springer Science and Business Media LLC, 2025-01-31) ; ;
    Saskya E. Carrera Pacheco
    ;
    Cristina Rodríguez-Pólit
    ;
    Carlos Barba-Ostria
    Schiff bases are organic compounds recognized for their biological activities, including antiviral, antibacterial, antifungal, and anticancer properties, making them promising candidates in medicinal chemistry. In this studio, a series of Schiff bases derived from 4-aminoantipyrine and substituted cinnamaldehydes were evaluated in vitro against liver (HepG2) and thyroid (THJ29T) cancer cells, Gram-positive and Gram-negative multidrug-resistant bacteria, and biofilm-forming pathogens. Six compounds demonstrated anticancer activity, though some exhibited toxicity to non-tumor cells. Compounds showed notable anticancer potential, while also exhibited strong antibacterial effects, with being the most effective against multidrug-resistant bacteria strains. These Schiff bases also inhibit biofilm formation, suggesting their potential for treating biofilm-related infections. analyses of their ADME properties, global reactivity descriptors, and binding affinities corroborated these findings. The Schiff base has a strong binding affinity for DNA gyrase and vitamin D receptor, suggesting potential mechanisms for its antibacterial and anticancer activities.
    Scopus© Citations 17
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    Bioactive Phenolic Compounds from Rambutan - Nephelium lappaceum L. - Shell: Encapsulation, Structural Stability, and Multifunctional Activities
    (MDPI AG, 2025-11-09)
    Carlos Barba Ostria
    ;
    Orestes López
    ;
    Alexis Debut
    ;
    ;
    Rambutan (Nephelium lappaceum) shell, an agro-industrial by-product, is a rich source of phenolic acids and minor anthocyanins, but its direct use is limited by instability and low bioavailability. We extracted phenolic-rich fractions and produced maltodextrin microcapsules by spray drying, then confirmed chemical entrapment and amorphization by FTIR, SEM, and XRD. The formulation showed high encapsulation efficiency and high antioxidant capacity (DPPH), selective bactericidal activity against Pseudomonas aeruginosa and Burkholderia cepacia, and strong inhibition of Staphylococcus aureus and Listeria monocytogenes biofilms, while exhibiting negligible hemolysis (&lt;2%) across tested concentrations. Antitumor effects were moderate with low selectivity in vitro, indicating that phenolic-acid-driven redox modulation may require fractionation or delivery optimization for oncology applications. Overall, spray-dried microcapsules provided structural stability and safety while concentrating multifunctional activities relevant to food and biomedical uses. By valorizing a tropical waste stream into a bioactive, hemocompatible ingredient, this work aligns with societal goals on health and sustainable production (SDG 3 and SDG 12) and offers a scalable route to deploy underutilized phenolic resources.</jats:p>
    Scopus© Citations 8
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    Exploring the Multifaceted Biological Activities of Anthocyanins Isolated from Two Andean Berries
    (MDPI AG, 2024-08-21)
    Carlos Barba-Ostria
    ;
    Saskya E. Carrera-Pacheco
    ;
    ; ;
    Natural pigments extracted from plant species are used in foods, cosmetics, and pharmaceuticals. This study evaluates the comprehensive biological activities of anthocyanins isolated from Andean blueberry (Vaccinium floribundum Kunth) and Andean blackberry (Rubus glaucus Benth), focusing on their antimicrobial, antioxidant, antitumoral, anti-inflammatory, and hemolytic properties. Chemical characterization revealed significant anthocyanin content with complex mass spectrometric profiles indicating diverse glycosylation patterns that may influence their bioactivity. The antimicrobial assays showed that the extracts were particularly effective against Gram-positive bacteria, with minimal inhibitory concentrations (MICs) as low as 1 mg/mL for Rubus glaucus, indicating strong potential for therapeutic use. The antioxidant capacity of the berries was substantial, albeit slightly lower than that of ascorbic acid. The extracts also exhibited notable antitumoral activity in various cancer cell lines, showing promise as adjunctive or preventive treatments. The anti-inflammatory effects were confirmed by inhibiting nitric oxide production in macrophage cells, highlighting their potential in managing inflammatory diseases. In terms of hemolytic activity, Rubus glaucus exhibited dose-dependent effects, potentially attributable to anthocyanins and phenolics, while Vaccinium floribundum demonstrated no significant hemolytic activity, underscoring its safety. These findings suggest that anthocyanins from Andean berries possess potent biological activities, which could be leveraged for health benefits in pharmaceutical and nutraceutical applications. Further studies are needed to isolate specific bioactive compounds and investigate their synergistic effects in clinical and real-world contexts.
    Scopus© Citations 13
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    Current Landscape of Methods to Evaluate Antimicrobial Activity of Natural Extracts
    (MDPI AG, 2023-01-20) ;
    Saskya E. Carrera-Pacheco
    ;
    ;
    Cristina Rodríguez-Pólit
    ;
    <jats:p>Natural extracts have been and continue to be used to treat a wide range of medical conditions, from infectious diseases to cancer, based on their convenience and therapeutic potential. Natural products derived from microbes, plants, and animals offer a broad variety of molecules and chemical compounds. Natural products are not only one of the most important sources for innovative drug development for animal and human health, but they are also an inspiration for synthetic biology and chemistry scientists towards the discovery of new bioactive compounds and pharmaceuticals. This is particularly relevant in the current context, where antimicrobial resistance has risen as a global health problem. Thus, efforts are being directed toward studying natural compounds’ chemical composition and bioactive potential to generate drugs with better efficacy and lower toxicity than existing molecules. Currently, a wide range of methodologies are used to analyze the in vitro activity of natural extracts to determine their suitability as antimicrobial agents. Despite traditional technologies being the most employed, technological advances have contributed to the implementation of methods able to circumvent issues related to analysis capacity, time, sensitivity, and reproducibility. This review produces an updated analysis of the conventional and current methods to evaluate the antimicrobial activity of natural compounds.</jats:p>
    Scopus© Citations 93
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    Evaluation of Biological Activity of Natural Compounds: Current Trends and Methods
    (MDPI AG, 2022-07-13)
    Carlos Barba-Ostria
    ;
    Saskya E. Carrera-Pacheco
    ;
    ;
    Cristina Rodríguez-Pólit
    ;
    <jats:p>Natural compounds have diverse structures and are present in different forms of life. Metabolites such as tannins, anthocyanins, and alkaloids, among others, serve as a defense mechanism in live organisms and are undoubtedly compounds of interest for the food, cosmetic, and pharmaceutical industries. Plants, bacteria, and insects represent sources of biomolecules with diverse activities, which are in many cases poorly studied. To use these molecules for different applications, it is essential to know their structure, concentrations, and biological activity potential. In vitro techniques that evaluate the biological activity of the molecules of interest have been developed since the 1950s. Currently, different methodologies have emerged to overcome some of the limitations of these traditional techniques, mainly via reductions in time and costs. These emerging technologies continue to appear due to the urgent need to expand the analysis capacity of a growing number of reported biomolecules. This review presents an updated summary of the conventional and relevant methods to evaluate the natural compounds’ biological activity in vitro.</jats:p>
    Scopus© Citations 146
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    Gene silencing based on RNA-guided catalytically inactive Cas9 (dCas9): a new tool for genetic engineering in Leptospira
    (Springer Science and Business Media LLC, 2019-02-12)
    L. G. V. Fernandes
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    ;
    S. A. Vasconcellos
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    Marcos B. Heinemann
    ;
    M. Picardeau
    <jats:title>Abstract</jats:title><jats:p>Leptospirosis is a worldwide zoonosis caused by pathogenic bacteria of the genus <jats:italic>Leptospira</jats:italic>, which also includes free-living saprophyte strains. Many aspects of leptospiral basic biology and virulence mechanisms remain unexplored mainly due to the lack of effective genetic tools available for these bacteria. Recently, the type II CRISPR/Cas system from <jats:italic>Streptococcus pyogenes</jats:italic> has been widely used as an efficient genome engineering tool in bacteria by inducing double-strand breaks (DSBs) in the desired genomic targets caused by an RNA-guided DNA endonuclease called Cas9, and the DSB repair associated machinery. In the present work, plasmids expressing heterologous <jats:italic>S. pyogenes</jats:italic> Cas9 in <jats:italic>L. biflexa</jats:italic> cells were generated, and the enzyme could be expressed with no apparent toxicity to leptospiral cells. However, <jats:italic>L. biflexa</jats:italic> cells were unable to repair RNA-guided Cas9-induced DSBs. Thus, we used a catalytically dead Cas9 (dCas9) to obtain gene silencing rather than disruption, in a strategy called CRISPR interference (CRISPRi). We demonstrated complete gene silencing in <jats:italic>L. biflexa</jats:italic> cells when both dCas9 and single-guide RNA (sgRNA) targeting the coding strand of the β-galactosidase gene were expressed simultaneously. Furthermore, when the system was applied for silencing the <jats:italic>dnaK</jats:italic> gene, no colonies were recovered, indicating that DnaK protein is essential in <jats:italic>Leptospira</jats:italic>. In addition, flagellar motor switch FliG gene silencing resulted in reduced bacterial motility. To the best of our knowledge, this is the first work applying the CRISPRi system in <jats:italic>Leptospira</jats:italic> and spirochetes in general, expanding the tools available for understanding leptospiral biology.</jats:p>
    Scopus© Citations 40
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    The Impact of Bioactive Molecules from Probiotics on Child Health: A Comprehensive Review
    (MDPI AG, 2024-10-30) ;
    Saskya E. Carrera-Pacheco
    ;
    ;
    Enrique Teran
    ;
    Cesar Erazo
    <jats:p>Background: This review investigates the impact of bioactive molecules produced by probiotics on child health, focusing on their roles in modulating gut microbiota, enhancing immune function, and supporting overall development. Key metabolites, including short-chain fatty acids (SCFAs), bacteriocins, exopolysaccharides (EPSs), vitamins, and gamma-aminobutyric acid (GABA), are highlighted for their ability to maintain gut health, regulate inflammation, and support neurodevelopment. Objectives: The aim of this review is to examine the mechanisms of action and clinical evidence supporting the use of probiotics and postbiotics in pediatric healthcare, with a focus on promoting optimal growth, development, and overall health in children. Methods: The review synthesizes findings from clinical studies that investigate the effects of probiotics and their metabolites on pediatric health. The focus is on specific probiotics and their ability to influence gut health, immune responses, and developmental outcomes. Results: Clinical studies demonstrate that specific probiotics and their metabolites can reduce gastrointestinal disorders, enhance immune responses, and decrease the incidence of allergies and respiratory infections in pediatric populations. Additionally, postbiotics—bioactive compounds from probiotic fermentation—offer promising benefits, such as improved gut barrier function, reduced inflammation, and enhanced nutrient absorption, while presenting fewer safety concerns compared to live probiotics. Conclusions: By examining the mechanisms of action and clinical evidence, this review underscores the potential of integrating probiotics and postbiotics into pediatric healthcare strategies to promote optimal growth, development, and overall health in children.</jats:p>
    Scopus© Citations 33
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    Engineering xylose metabolism for production of polyhydroxybutyrate in the non-model bacterium Burkholderia sacchari
    (Springer Science and Business Media LLC, 2018-05-15) ;
    Carlos Barba-Ostria
    ;
    Fuzhong Zhang
    ;
    Edmar R. Oliveira-Filho
    ;
    José Gregório C. Gomez
    Scopus© Citations 27
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    Chemical Properties and Biological Activity of Bee Pollen
    (MDPI AG, 2023-11-25)
    Cristina Rodríguez-Pólit
    ;
    ;
    Roberto Vallejo-Imbaquingo
    ;
    Carlos Barba-Ostria
    ;
    <jats:p>Pollen, a remarkably versatile natural compound collected by bees for its abundant source of proteins and nutrients, represents a rich reservoir of diverse bioactive compounds with noteworthy chemical and therapeutic potential. Its extensive biological effects have been known and exploited since ancient times. Today, there is an increased interest in finding natural compounds against oxidative stress, a factor that contributes to various diseases. Recent research has unraveled a multitude of biological activities associated with bee pollen, ranging from antioxidant, anti-inflammatory, antimicrobial, and antifungal properties to potential antiviral and anticancer applications. Comprehending the extensive repertoire of biological properties across various pollen sources remains challenging. By investigating a spectrum of pollen types and their chemical composition, this review produces an updated analysis of the bioactive constituents and the therapeutic prospects they offer. This review emphasizes the necessity for further exploration and standardization of diverse pollen sources and bioactive compounds that could contribute to the development of innovative therapies.</jats:p>
    Scopus© Citations 54
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    Phytochemical Composition and Biological Properties of Macleania rupestris Fruit Extract: Insights into Its Antimicrobial and Antioxidant Activity
    (MDPI AG, 2025-03-27) ; ;
    Elena Coyago-Cruz
    ;
    ;
    Jéssica Guamán-Bautista
    Macleania rupestris, a fruit-bearing species of the Ericaceae family, has traditionally been used for its potential medicinal properties. Background/Objectives: This study investigates the phytochemical composition and antimicrobial activity of M. rupestris fruit extract, focusing on its antibacterial, antibiofilm, and antifungal effects. Methods: M. rupestris (Kunth) A.C.Sm. berries (code: 4456, Herbario QUPS-Ecuador) were collected from the cloud forest Montano Alto, Cuenca-Ecuador, and the extract was obtained using an ethanolic-based extraction and chemically characterized. The antibacterial and antifungal activity of the fruit extract was assessed against seven multidrug-resistant bacteria strains and four fungal strains using the microdilution method. The biofilm inhibition potential was evaluated using a microplate assay with the crystal violet staining method. The antioxidant activity was evaluated using DPPH and ABTS assays. Results: The bioactive compounds showed 853.9 mg phenols/100 g DW, 573.2 mg organic acid/100 g DW, and 21.5 mg C-3-gl/100 g DW of anthocyanins. The antibacterial assays demonstrated significant inhibitory activity against Enterococcus faecalis, Enterococcus faecium, Escherichia coli, and Staphylococcus epidermidis, with MIC values ranging from 1.25 to 5 mg/mL. Additionally, the biofilm inhibition assays confirmed the potential of M. rupestris extract to disrupt bacterial biofilms, particularly in S. aureus and L. monocytogenes. Nevertheless, no significant antifungal activity was observed against Candida spp., suggesting selective antimicrobial properties. Finally, the antioxidant activity was strong (1.62 mmol TE/100 g DW by DPPH and 3.28 mmol TE/100 g DW by ABTS). Conclusions: These findings indicate that M. rupestris possesses promising antibacterial, antibiofilm, and antioxidant properties, which may be attributed to its phenolic and organic acid composition. Further fractionation and targeted bioassays are required to elucidate the specific bioactive compounds responsible for these effects and explore their potential applications in antimicrobial formulations.
    Scopus© Citations 7