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21 result(s) for "Hernández-Álvarez, Eduardo"
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Eco-Friendly Crop Protection: Argyrantemum frutescens, a Source of Biofungicides
Plant-derived biopesticides are emerging as a promising and popular alternative for promoting cleaner and safer agricultural practices. The present work aims to explore Argyranthemum frutescens (Asteraceae) as a source of botanical pesticides and to validate this through a cultivation process. To this task, a bioassay-guided fractionation of the ethanolic root extracts from both wild and cultivated A. frutescens on phytopathogenic fungi of Botrytis cinerea, Fusarium oxysporum, and Alternaria alternata was conducted. This approach led to the identification of polyacetylenes with higher potency than commercial fungicides. Specifically, compounds 3 (capillin) and 5 (frutescinone) showed more than 90% growth inhibition at 0.05 mg/mL concentration on B. cinerea, while compounds 2 (capillinol) and 3 were also more active than positive controls, Fosbel-Plus and Azoxystrobin, against F. oxysporum. The structures of the isolated polyacetylenes (1–6, 9, and 10) and alkamides (7, 8, and 11) were determined through spectroscopic analysis, and the absolute configuration of stereocenter C1 of compounds 1, 2, 4 and 9 was determined by NMR-spectroscopy with (R)-(-)-α-methoxy-phenylacetic as a chiral derivatizing agent, and biogenetic considerations. Overall, this study supports the potential of polyacetylenes as promising agrochemical lead compounds against phytopathogens, and validates A. frutescens cultivation as a viable source of biopesticides.
Bioassay-Guided Fractionation Networking for Discovery of Biofungicides from Cultivated Salvia canariensis
Considering the detrimental impacts of the current pesticides on the biotic components of the biosphere, the development of novel pesticides is vital. Plant-derived biopesticides have emerged as popular alternatives to create a safer and more sustainable agriculture model. This study aims to validate the previous bioguided fractionation of endemic Canary Islands sage, Salvia canariensis, as a potential source of botanical pesticides using a cultivation process. Accordingly, the bioassay-guided fractionation of the ethanolic extract of the leaves of cultivated S. canariensis on the phytopathogenic fungal mycelia of Botrytis cinerea, Fusarium oxysporum, and Alternaria alternata yielded six known terpenoids. Their abietane diterpenoid-type (1–5) and sesquiterpenoid (6) structures were established based on spectroscopic and spectrometric analysis. This strategy identified one abietane diterpenoid, salviol (5), as a potential candidate for the future development of biofungicides with similar potency towards the assayed phytopathogenic fungi to commercial fungicides. Salviol worked in a concentration-dependent manner. Overall, this study reinforces the potential of abietane-type diterpenoids as promising agrochemical lead compounds against infectious diseases caused by phytopathogenic fungi and validates the cultivation of S. canariensis as a potential source of plant-derived biopesticides.
Mechanism Insight of Cell Death Signaling by Thymol Derivatives on Trypanosomatidae Protozoan Parasites
Leishmaniasis and Chagas disease are parasitic diseases considered to be among the most important neglected diseases, with implications for both developed and developing countries. Currently, there are no effective therapeutic treatments for these diseases due to challenges in drug administration, high toxicity, high costs, and drug resistance. In this study, a series of eleven thymol derivatives were designed, synthesized, and evaluated for their in vitro kinetoplastid activity against Leishmania amazonensis and Trypanosoma cruzi, as well as their cytotoxicity against a murine macrophage cell line. The most active compounds, thymol anysoate (9) and thymol picolinate (10), displayed the highest kinetoplastid activity with IC50 values of 22.87 and 25.16 µM against L. amazonensis and T. cruzi, respectively. Notably, both compounds demonstrated an excellent selectivity index against the mammal cell line. Structure–activity relationship studies revealed that the ester group plays a crucial role in activity. The most promising derivatives, 9 and 10, activate autophagy and apoptosis-like processes in the treated cells. Atomic force microscopy observations showed that derivative 9 induces the formation of cytoplasmic vacuoles, indicating an autophagic process, and drug-likeness analysis revealed that it meets all the pharmacokinetic criteria. Overall, these results highlight derivative 9 as a potential lead compound for the development of new drugs for the treatment of Trypanosomatidae infections and warrants further studies to elucidate the cell death cascade involved.
Mentha rotundifolia, a Source of Amoebicidal Agents Against Naegleria fowleri
Current therapies for Primary Amoebic Meningoencephalitis (PAM) present several limitations; consequently, there is an urgent need to develop new therapeutic agents. In this regard, we undertook bioassay-guided isolation of Mentha rotundifolia leaves which allowed the identification of ursolic acid (1) as the main bioactive metabolite against two ATCC strains of Naegleria fowleri (ATCC® 30808TM and ATCC® 30215TM). Moreover, ten ursolic acid derivatives (2–11) were synthesized through esterification and nucleophilic substitution to obtain halo or amino ester derivatives. Among these derivatives, compound 7 exhibited the highest activity against the N. fowleri ATCC® 30808TM strain with an IC50 value of 28.66 µM, whereas compound 10 showed the top activity against the N. fowleri ATCC® 30215TM strain with an IC50 of 7.61 µM, surpassing the efficacy of the reference drug, miltefosine. Both compounds, 7 and 10, showed a good selectivity index and hence low toxicity in vitro. Structure–activity relationship studies revealed that the type of acylating agent played a crucial role in the activity. Furthermore, both compounds induced autophagy and apoptosis-like processes in both treated N. fowleri strains. These results highlight the potential of ursolic acid-related triterpenoids as drug scaffolds and identify M. rotundifolia as a promising natural source of amoebicidal agents against PAM.
Diels–Alder Adducts from Maytenus chiapensis
Natural products from plants have played an important role in cancer and neurodegenerative diseases. In this context, the root bark of Maytenus chiapensis (Celastraceae) was investigated to examine its chemical constituents and potential biological activities. Chromatographic separation of the root bark extract yielded a new Diels–Alder adduct (morenine) formed by a triterpenophenolic moiety derived from tingenone and a bicyclic guaiane-type sesquiterpene linked through a 1,4-dioxane bridge. In addition, eight previously reported Diels–Alder adducts—retusonine and cheiloclines A–D and F–H—were isolated, together with their biosynthetic precursors, the quinone-methide triterpenoids (QMTs) pristimerin and tingenone. Structural elucidation was achieved through detailed 1D and 2D NMR spectroscopic analyses. The adducts were tested for cytotoxicity against six cancer cell lines (A549, SW1573, MIA PaCa-2, T-47D, HeLa, and WiDr cell lines), showing moderate-to-low activity compared with their precursors. Continuous live cell imaging identified apoptosis and vacuole formation as the main modes of action of pristimerin in SW1573 cells. Moreover, acetylcholinesterase inhibition assays revealed that cheiloclines B–D, F, and H exhibited up to 50% inhibition. These findings reinforce the potential of Celastraceae species as a source of unique and complex compounds and enhance our understanding of their therapeutic potential.
Bioprospecting for Anti-Kinetoplastid Drug Discovery from Aloysia citrodora Essential Oil
Natural products have long been recognized as invaluable resources in drug discovery. Essential oils have attracted widespread attention due to their broad spectrum of biological activities. Herein, we report the anti-kinetoplastid activity of Aloysia citrodora leaf essential oil through a bioassay-guided fractionation method against the etiological agents of Chagas disease and leishmaniasis. This approach has led to the isolation and structural identification of compound 1 (citral) as the main active constituent, with IC50 values of 8.47 μM against Leishmania amazonensis and 12.90 μM against Trypanosoma cruzi. In addition, eight compounds (2–9) were synthesized and evaluated. Among these, citral 2,4-dinitrophenylhydrazone (9) exhibited the highest anti-kinetoplastid activity, with an IC50 value of 10.62 μM against L. amazonensis, displaying a similar biological profile to citral and the reference drug. Structure–activity relationship studies revealed that the type of Schiff base and acylating agent played a crucial role in the activity. Mechanism of action studies demonstrated that compound 9 directly targets the apoptotic pathway, inducing programmed cell death through selective pathway inhibition. This work underscores the potential of A. citrodora essential oil and its compounds as prospective therapeutic leads against neglected tropical diseases.
Apoptosis: Activation and Inhibition in Health and Disease
There are many types of cell death, each involving multiple and complex molecular events. Cell death can occur accidentally when exposed to extreme physical, chemical, or mechanical conditions, or it can also be regulated, which involves a genetically coded complex machinery to carry out the process. Apoptosis is an example of the latter. Apoptotic cell death can be triggered through different intracellular signalling pathways that lead to morphological changes and eventually cell death. This is a normal and biological process carried out during maturation, remodelling, growth, and development in tissues. To maintain tissue homeostasis, regulatory, and inhibitory mechanisms must control apoptosis. Paradoxically, these same pathways are utilized during infection by distinct intracellular microorganisms to evade recognition by the immune system and therefore survive, reproduce and develop. In cancer, neoplastic cells inhibit apoptosis, thus allowing their survival and increasing their capability to invade different tissues and organs. The purpose of this work is to review the generalities of the molecular mechanisms and signalling pathways involved in apoptosis induction and inhibition. Additionally, we compile the current evidence of apoptosis modulation during cancer and Leishmania infection as a model of apoptosis regulation by an intracellular microorganism.
Long-Term Benefit of Perlingual Polybacterial Vaccines in Patients with Systemic Autoimmune Diseases and Active Immunosuppression
Introduction: We have previously shown that trained-immunity-based vaccines, namely TIbV, significantly reduce the rate of recurrent infections, both of the respiratory tract (RRTI) and urinary tract infections (RUTI) in SAD patients on disease-modifying drugs (DMARDs). Objective: We evaluated the frequency of RRTI and RUTI from 2018 to 2021 in those SAD patients that received TIbV until 2018. Secondarily, we evaluated the incidence and clinical course of COVID-19 in this cohort. Methods: A retrospective observational study was conducted in a cohort of SAD patients under active immunosuppression immunized with TIbV (MV130 for RRTI and MV140 for RUTI, respectively). Results: Forty-one SAD patients on active immunosuppression that were given TIbV up to 2018 were studied for RRTI and RUTI during the 2018–2021 period. Approximately half of the patients had no infections during 2018–2021 (51.2% no RUTI and 43.5% no RRTI at all). When we compared the 3-year period with the 1-year pre-TIbV, RRTI (1.61 ± 2.26 vs. 2.76 ± 2.57; p = 0.002) and RUTI (1.56 ± 2.12 vs. 2.69 ± 3.07; p = 0.010) episodes were still significantly lower. Six SAD patients (four RA; one SLE; one MCTD) with RNA-based vaccines were infected with SARS-CoV-2, with mild disease. Conclusions: Even though the beneficial protective effects against infections of TIbV progressively decreased, they remained low for up to 3 years, with significantly reduced infections compared to the year prior to vaccination, further supporting a long-term benefit of TIbV in this setting. Moreover, an absence of infections was observed in almost half of patients.
Pan-American League of Associations for Rheumatology (PANLAR) capillaroscopy study group consensus for the format and content of the report in capillaroscopy in rheumatology
ObjectiveThe aim of this work was to produce a consensus-based report for capillaroscopy in rheumatology to be used in daily clinical practice.MethodsA written Delphi questionnaire regarding capillaroscopy report was developed from a literature review and expert consensus. The Delphi questionnaire was sent to an international panel including 25 rheumatologists experts in capillaroscopy, asking them to rate their level of agreement or disagreement with each statement. The exercise consisted of three online rounds and a face-to-face (live meeting) that took place in the PANLAR 2018 congress held in Buenos Aires, Argentina.ResultsThe participants to the first, second, third, and face-to-face round were 22, 21, 21, and 16 rheumatologists, respectively. Fifty-five items were discussed in the first round, 58 in the second, 22 in the third, and 9 in the face-to-face meeting. At the end of the exercise, 46 recommendations for the capillaroscopy report in rheumatology reached a consensus.ConclusionThis is the first consensus-based report in capillaroscopy. It will be useful in daily clinical practice and to address the effort of the standardization in the technique.Key Points• The current lack of consensus for the capillaroscopy report makes difficult the interpretation of findings as well as follow-up of rheumatic diseases.• This study produced the first international consensus for the format and content of the naifold capillaroscopy report in rheumatology.• The report is an integral part of the capillaroscopy examination and its use in a homogeneous form can help in the correct interpretation of findings in daily practice.
Essential and Non-essential Elements in an Herbaceous Karst Wetland: Inputs from Urban Dust
Wetlands play an important role in biogeochemical cycles, as their hydrological and edaphic properties drive chemical reactions that facilitate the storage or transfer of various elements. Some herbaceous wetlands are ecosystems dominated by grass-like communities, sedges and rushes, and the information available at international level reveals they are poorly studied ecosystems in terms of elemental analysis. This research seeks to contribute to the understanding of herbaceous wetlands producing an inventory of essential and non-essential elements, the latter expected to be increased from the direct interaction of the wetland with a road. Several elements, divided into four major groups (macro-elements, micro-elements, trace elements and non-essential elements), were quantitatively analyzed in five environmental matrices (interstitial water, sediments, vegetal aerial parts and roots, and snail shells) as well as urban dust, for the purpose of finding out whether urban dust from the road was a fixed source of non-essential elements for the wetland. Based on our findings, we report the presence of 24 elements (calcium, potassium, magnesium, phosphorus, iron, nickel, chromium, manganese, copper, zinc, silicon, barium, cobalt, molybdenum, selenium, vanadium, sodium, aluminum, cadmium, lead, antimony, arsenic, thallium and mercury), not all of them reported in all samples. We found several elements in highest concentrations in the portion of the wetland closest to the road, in water (Cu and Tl), sediments (Fe, Cr, Cu, V and Tl), aerial tissue of the plants (Mn, Co, V, Cd, Pb and As) and plants roots (Ni, Cr, Cu, Zn, Co, Mo, V, Al, Cd, Se, Pb and As). These elements overlap with those found in urban dust (Fe, Ni, Cr, Mn, Cu, Zn, Ba, Co, V, Cd, Pb, As, Tl), supporting the hypothesis that the road might be a source of both essential and non-essential elements to the wetland.