Nucleation and Initial Stages of Growth during the Atomic Layer Deposition of Titanium Oxide on Mesoporous Silica.

A chemical approach to the deposition of thin films on solid surfaces is highly desirable but prone to affect the final properties of the film. To better understand the origin of these complications, the initial stages of the atomic layer deposition of titania films on silica mesoporous materials were characterized. Adsorption-desorption measurements indicated that the films grow in a layer-by-layer fashion, as desired, but initially exhibit surprisingly low densities, about one-quarter of that of bulk titanium oxide. Electron microscopy, X-ray diffraction, UV/visible, and X-ray absorption spectroscopy data pointed to the amorphous nature of the first monolayers, and EXAFS and 29Si CP/MAS NMR results to an initial growth via the formation of individual tetrahedral Ti-oxide units on isolated Si-OH surface groups with unusually long Ti-O bonds. Density functional theory calculations were used to propose a mechanism where the film growth starts at the nucleation centers to form an open 2D structure.

Direct Conversion of Methane to Methanol on Ni-Ceria Surfaces: Metal-Support Interactions and Water-Enabled Catalytic Conversion by Site Blocking.

The transformation of methane into methanol or higher alcohols at moderate temperature and pressure conditions is of great environmental interest and remains a challenge despite many efforts. Extended surfaces of metallic nickel are inactive for a direct CH4 → CH3OH conversion. This experimental and computational study provides clear evidence that low Ni loadings on a CeO2(111) support can perform a direct catalytic cycle for the generation of methanol at low temperature using oxygen and water as reactants, with a higher selectivity than ever reported for ceria-based catalysts. On the basis of ambient pressure X-ray photoemission spectroscopy and density functional theory calculations, we demonstrate that water plays a crucial role in blocking catalyst sites where methyl species could fully decompose, an essential factor for diminishing the production of CO and CO2, and in generating sites on which methoxy species and ultimately methanol can form. In addition to water-site blocking, one needs the effects of metal-support interactions to bind and activate methane and water. These findings should be considered when designing metal/oxide catalysts for converting methane to value-added chemicals and fuels.

Enhanced, robust light-driven H2 generation by gallium-doped titania nanoparticles.

The splitting of water into molecular hydrogen and oxygen with the use of renewable solar energy is considered one of the most promising routes to yield sustainable fuel. Herein, we report the H2 evolution performance of gallium doped TiO2 photocatalysts with varying degrees of Ga dopant. The gallium(iii) ions induced significant changes in the structural, textural and electronic properties of TiO2 nanoparticles, resulting in remarkably enhanced photocatalytic activity and good stability for H2 production. Ga3+ ions can act as hole traps that enable a large number of excited electrons to migrate towards the TiO2 surface, thereby facilitating electron transfer and charge separation. Additionally, the cationic dopant and its induced defects might introduce a mid-gap state, promoting electron migration and prolonging the lifetime of charge carrier pairs. We have discovered that the optimal Ga dopant concentration was 3.125 at% and that the incorporation of platinum (0.5 wt%) as a co-catalyst further improved the H2 evolution rate up to 5722 µmol g-1 h-1. Pt not only acts as an electron sink, drastically increasing the electron/hole pair lifetime, but it also creates an intimate contact at the heterojunction between Pt and Ga-TiO2, thus improving the interfacial electron transfer process. These catalyst design strategies provide new ways of designing transition metal photocatalysts that improve green fuel production from renewable solar energy and water.

Imaging the ordering of a weakly adsorbed two-dimensional condensate: ambient-pressure microscopy and spectroscopy of CO2 molecules on rutile TiO2(110).

Disorder-Order transitions in a weakly adsorbed two-dimensional film have been identified for the first time using ambient-pressure scanning tunneling microscopy (AP-STM) and X-ray photoelectron spectroscopy (AP-XPS). As of late, great effort has been devoted to the capture, activation and conversion of carbon dioxide (CO2), a ubiquitous greenhouse gas and by-product of many chemical processes. The high stability and non-polar nature of CO2 leads to weak bonding with well-defined surfaces of metals and oxides. CO2 adsorbs molecularly on the rutile TiO2(110) surface with a low adsorption energy of ∼10 kcal mol-1. In spite of this weak binding, images of AP-STM show that a substantial amount of CO2 can reside on a TiO2(110) surface at room temperature forming two-dimensionally ordered films. We have employed microscopic imaging under in situ conditions, soft X-ray spectroscopy and theory to decipher the unique ordering behavior seen for CO2 on TiO2(110).

Ceria-based model catalysts: fundamental studies on the importance of the metal-ceria interface in CO oxidation, the water-gas shift, CO2 hydrogenation, and methane and alcohol reforming.

Model metal/ceria and ceria/metal catalysts have been shown to be excellent systems for studying fundamental phenomena linked to the operation of technical catalysts. In the last fifteen years, many combinations of well-defined systems involving different kinds of metals and ceria have been prepared and characterized using the modern techniques of surface science. So far most of the catalytic studies have been centered on a few reactions: CO oxidation, the hydrogenation of CO2, and the production of hydrogen through the water-gas shift reaction and the reforming of methane or alcohols. Using model catalysts it has been possible to examine in detail correlations between the structural, electronic and catalytic properties of ceria-metal interfaces. In situ techniques (X-ray photoelectron spectroscopy, X-ray absorption spectroscopy, infrared spectroscopy, scanning tunneling microscopy) have been combined to study the morphological changes under reaction conditions and investigate the evolution of active phases involved in the cleavage of C-O, C-H and C-C bonds. Several studies with model ceria catalysts have shown the importance of strong metal-support interactions. In general, a substantial body of knowledge has been acquired and concepts have been developed for a more rational approach to the design of novel technical catalysts containing ceria.

Cu supported on mesoporous ceria: water gas shift activity at low Cu loadings through metal-support interactions.

We have synthesized and tested a highly active Cu doped mesoporous CeO2 catalyst system for the low temperature water-gas shift (WGS) reaction. While typical oxide-supported copper WGS catalysts are characterized by high copper loadings (30-40%), the morphological properties of the mesoporous CeO2 material enable high catalytic activity at copper loadings as low as 1%. Operando X-ray diffraction, in situ X-ray absorption near-edge structure spectroscopy (XANES), and operando diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) methods were used to probe the interactions between the metal and mesoporous oxide components under reaction conditions. Copper was observed to undergo reduction from oxide to metal under WGS conditions at 150 °C, while the CeO2 lattice was observed to expand upon heating, indicating Ce3+ formation correlated with CO2 production. The active state of the catalysts was confirmed by in situ XANES to contain Cu0 and partially reduced CeO2. DRIFTS analysis revealed carboxyl species bound to copper during reduction, as well as formate and carbonate surface species on ceria. Lower concentrations of copper were observed to foster enhanced metal-support interactions.

In†Situ Investigation of Methane Dry Reforming on Metal/Ceria(111) Surfaces: Metal-Support Interactions and C-H Bond Activation at Low Temperature.

Studies with a series of metal/ceria(111) (metal=Co, Ni, Cu; ceria=CeO2 ) surfaces indicate that metal-oxide interactions can play a very important role for the activation of methane and its reforming with CO2 at relatively low temperatures (600-700 K). Among the systems examined, Co/CeO2 (111) exhibits the best performance and Cu/CeO2 (111) has negligible activity. Experiments using ambient pressure X-ray photoelectron spectroscopy indicate that methane dissociates on Co/CeO2 (111) at temperatures as low as 300 K-generating CHx and COx species on the catalyst surface. The results of density functional calculations show a reduction in the methane activation barrier from 1.07 eV on Co(0001) to 0.87 eV on Co2+ /CeO2 (111), and to only 0.05 eV on Co0 /CeO2-x (111). At 700 K, under methane dry reforming conditions, CO2 dissociates on the oxide surface and a catalytic cycle is established without coke deposition. A significant part of the CHx formed on the Co0 /CeO2-x (111) catalyst recombines to yield ethane or ethylene.

Pan-immune-inflammation value and survival in patients with breast cancer from a Peruvian reference hospital.

The pan-immune-inflammation value (PIV), calculated as (neutrophil × platelet × monocyte)/lymphocyte count, may be useful for estimating survival in breast cancer patients. To determine the prognostic value of PIV for overall survival in breast cancer patients in Lima, Peru. A retrospective cohort study was conducted. 97 breast cancer patients diagnosed between January 2010 and December 2016 had their medical records analyzed. The primary dependent variable was overall survival, and the key independent variable was the PIV, divided into high (≥ 310) and low (< 310) groups. Patient data included demographics, treatment protocols and other clinical variables. Statistical analysis involved Kaplan-Meier survival curves and Cox proportional hazards modeling. Patients with a PIV ≥ 310 had significantly lower 5-year survival functions (p = 0.004). Similar significant differences in survival were observed for clinical stage III-IV (p = 0.015), hemoglobin levels < 12 mg/Dl (p = 0.007), histological grade (p = 0.019), and nuclear grade (p < 0.001); however, molecular classification did not show a significant survival difference (p = 0.371). The adjusted Hazard Ratios showed that PIV ≥ 310 was significantly associated with poor outcome (5.08, IC95%: 1.52-16.92). While clinical stage and hemoglobin levels were associated with survival in the unadjusted model. These factors did not maintain significance after adjustment. PIV is an independent predictor of reduced survival in Peruvian breast cancer patients.

Inflammatory markers related to survival in breast cancer patients: Peru.

INTRODUCTION: Breast cancer is a disease with high global prevalence. Clinical inflammatory biomarkers have been proposed as prognostic indicators in oncology. This research aims to determine the relationship between inflammatory markers and overall survival in breast cancer patients from four representative hospitals in Lima, Peru. METHODS: This is a multicentric, analytical, longitudinal retrospective cohort study with survival analysis in female patients with breast cancer, from 2015 to 2020, who had received at least one complete treatment regimen. The dependent variable was overall survival, and the independent variables were inflammatory markers neutrophil lymphocyte ratio, platelet lymphocyte ratio (PLR), albumin, and red cell distribution width; intervening variables included age, clinical stage, molecular subtype, and other known prognostic factors. The Kaplan-Meier method was applied to generate survival curves with the Log-Rank test, and finally, Cox regression, to find crude and adjusted hazard ratios (HR). RESULTS: Of 705 evaluated patients, 618 were analyzed. The mean age was 56.6 ± 12.3 years, 18.0% of patients were pure HER2 positive, 39.3% luminal A, 29.9% luminal B, 11.0% triple-negative, and 81.4% showed overweight and obesity. The average overall survival was 51.1 months. In the multivariate analysis, factors significantly related to lower overall survival were PLR > 150 (adjusted HR: 2.33; 95% confidence interval (CI): 1.22, 4.44) and stage III (adjusted HR: 4.15; 95% CI: 1.35, 12.83). CONCLUSIONS: The Elevated Platelet-Lymphocyte Index and advanced clinical stage were associated with lower overall survival in breast cancer patients. Furthermore, PLR >150 proved to be an independent prognostic factor for mortality.

Redox Properties of TiO2 Thin Films Grown on Mesoporous Silica by Atomic Layer Deposition.

The redox properties of titania films grown by ALD on SBA-15, a silica-based mesoporous material, were characterized as a function of thickness (that is, the number of ALD cycles used). 29Si CP/MAS NMR helped to identify the nature of the surface species that form in the initial stages of deposition, and infrared absorption spectroscopy was used to follow the transition from silica to titania surfaces. The reducibility of the titania sites by CO and H2 was studied ex situ using EPR and in situ with ambient-pressure XPS. It was determined that the titania ALD films are amorphous and easier to reduce than crystalline titania and that the reduction is reversible. A transition in the nature of the surface was also observed, with unique mixed Si-O-Ti sites forming during the first few ALD cycles and a more typical titania surface progressively developing as the film grows in thickness.

Reaction Pathway for Coke-Free Methane Steam Reforming on a Ni/CeO2 Catalyst: Active Sites and the Role of Metal-Support Interactions.

Methane steam reforming (MSR) plays a key role in the production of syngas and hydrogen from natural gas. The increasing interest in the use of hydrogen for fuel cell applications demands development of catalysts with high activity at reduced operating temperatures. Ni-based catalysts are promising systems because of their high activity and low cost, but coke formation generally poses a severe problem. Studies of ambient-pressure X-ray photoelectron spectroscopy (AP-XPS) indicate that CH4/H2O gas mixtures react with Ni/CeO2(111) surfaces to form OH, CH x , and CH x O at 300 K. All of these species are easy to form and desorb at temperatures below 700 K when the rate of the MSR process is accelerated. Density functional theory (DFT) modeling of the reaction over ceria-supported small Ni nanoparticles predicts relatively low activation barriers between 0.3 and 0.7 eV for complete dehydrogenation of methane to carbon and the barrierless activation of water at interfacial Ni sites. Hydroxyls resulting from water activation allow for CO formation via a COH intermediate with a barrier of about 0.9 eV, which is much lower than that through a pathway involving lattice oxygen from ceria. Neither methane nor water activation is a rate-determining step, and the OH-assisted CO formation through the COH intermediate constitutes a low-barrier pathway that prevents carbon accumulation. The interactions between Ni and the ceria support and the low metal loading are crucial for the reaction to proceed in a coke-free and efficient way. These results pave the way for further advances in the design of stable and highly active Ni-based catalysts for hydrogen production.

Water-promoted interfacial pathways in methane oxidation to methanol on a CeO2-Cu2O catalyst.

Highly selective oxidation of methane to methanol has long been challenging in catalysis. Here, we reveal key steps for the pro-motion of this reaction by water when tuning the selectivity of a well-defined CeO2/Cu2O/Cu(111) catalyst from carbon monoxide and carbon dioxide to methanol under a reaction environment with methane, oxygen, and water. Ambient-pressure x-ray photoelectron spectroscopy showed that water added to methane and oxygen led to surface methoxy groups and accelerated methanol production. These results were consistent with density functional theory calculations and kinetic Monte Carlo simulations, which showed that water preferentially dissociates over the active cerium ions at the CeO2-Cu2O/Cu(111) interface. The adsorbed hydroxyl species blocked O-O bond cleavage that would dehydrogenate methoxy groups to carbon monoxide and carbon dioxide, and it directly converted this species to methanol, while oxygen reoxidized the reduced surface. Water adsorption also displaced the produced methanol into the gas phase.

Correlated Multimodal Approach Reveals Key Details of Nerve-Agent Decomposition by Single-Site Zr-Based Polyoxometalates.

Development of technologies for protection against chemical warfare agents (CWAs) is critically important. Recently, polyoxometalates have attracted attention as potential catalysts for nerve-agent decomposition. Improvement of their effectiveness in real operating conditions requires an atomic-level understanding of CWA decomposition at the gas-solid interface. We investigated decomposition of the nerve agent Sarin and its simulant, dimethyl chlorophosphate (DMCP), by zirconium polytungstate. Using a multimodal approach, we showed that upon DMCP and Sarin exposure the dimeric tungstate undergoes monomerization, making coordinatively unsaturated Zr(IV) centers available, which activate nucleophilic hydrolysis. Further, DMCP is shown to be a good model system of reduced toxicity for studies of CWA deactivation at the gas-solid interface.

La inmunoterapia en el manejo del cáncer renal metastásico: En tratamiento con inhibidores de checkpoint PD-L1 y/o anti-CTLA-4. A propósito de un caso / Case report about immunotherapy in management of metastatic renal cancer: Treatment with checkpoint PD-L1 and/or anti-CTLA-4 inhibitors

RESUMEN El carcinoma de células renales (CCR) aproximadamente el 15 por ciento se presentan como localmente avanzado o metastásico, donde la cirugía no es curativa. El pronóstico de los pacientes con CCR avanzado o metastásico puede variar desde unos meses hasta algunos años, según las características clínicas, patológicas, radiológicas de la enfermedad. El advenimiento del uso de anti monoclonales basado en la inmunoterapia como inhibidores de puntos de control en la terapia sistémica inicial para el CCR avanzado de células claras. Presentaremos un caso clínico donde la inmunoterapia juega un rol mediante el uso de anti monoclonales para el abordaje de un paciente varón con enfermedad renal metastásica que presenta respuesta clínica después del tratamiento quirúrgico e inmunoterapia por 2 años sin evidencia de enfermedad oncológica hasta la actualidad.

ABSTRACT Approximately 15 percent of renal cell carcinoma (RCC) present as locally advanced or metastatic, where surgery is not curative. The prognosis of patients with advanced or metastatic RCC can vary from a few months to a few years, depending on the clinical, pathological, and radiological characteristics of the disease. The advent of the use of anti-monoclonal-based immunotherapy as checkpoint inhibitors in initial systemic therapy for advanced clear cell RCC. We will present a clinical case where immunotherapy plays a role through the use of anti-monoclonal drugs to treat a male patient with metastatic kidney disease who presents a clinical response after surgical treatment and immunotherapy for 2 years without evidence of oncological disease to date.

Unexpected visible light driven photocatalytic activity without cocatalysts and sacrificial reagents from a (GaN)1-x (ZnO) x solid solution synthesized at high pressure over the entire composition range.

Optical and photocatalytic properties were determined for the solid solution series (GaN)1-x (ZnO) x synthesized at high pressure over the entire compositional range (x = 0.07 to 0.9). We report for the first time photocatalytic H2 evolution activity from water for (GaN)1-x (ZnO) x without cocatalysts, pH modifiers and sacrificial reagents. Syntheses were carried out by reacting GaN and ZnO in appropriate amounts at temperatures ranging from 1150 to 1200 °C, and at a pressure of 1 GPa. ZnGa2O4 was observed as a second phase, with the amount decreasing from 12.8 wt% at x = 0.07 to ∼0.5 wt% at x = 0.9. The smallest band gap of 2.65 eV and the largest average photocatalytic H2 evolution rate of 2.31 µmol h-1 were observed at x = 0.51. Samples with x = 0.07, 0.24 and 0.76 have band gaps of 2.89 eV, 2.78 eV and 2.83 eV, and average hydrogen evolution rates of 1.8 µmol h-1, 0.55 µmol h-1 and 0.48 µmol h-1, respectively. The sample with x = 0.9 has a band gap of 2.82 eV, but did not evolve hydrogen. An extended photocatalytic test showed considerable reduction of activity over 20 hours.

Hydrogenation of CO2 on ZnO/Cu(100) and ZnO/Cu(111) Catalysts: Role of Copper Structure and Metal-Oxide Interface in Methanol Synthesis.

The results of kinetic tests and ambient-pressure X-ray photoelectron spectroscopy (AP-XPS) show the important role played by a ZnO-copper interface in the generation of CO and the synthesis of methanol from CO2 hydrogenation. The deposition of nanoparticles of ZnO on Cu(100) and Cu(111), θoxi < 0.3 monolayer, produces highly active catalysts. The catalytic activity of these systems increases in the sequence: Cu(111) < Cu(100) < ZnO/Cu(111) < ZnO/Cu(100). The structure of the copper substrate influences the catalytic performance of a ZnO-copper interface. Furthermore, size and metal-oxide interactions affect the chemical and catalytic properties of the oxide making the supported nanoparticles different from bulk ZnO. The formation of a ZnO-copper interface favors the binding and conversion of CO2 into a formate intermediate that is stable on the catalyst surface up to temperatures above 500 K. Alloys of Zn with Cu(111) and Cu(100) were not stable at the elevated temperatures (500-600 K) used for the CO2 hydrogenation reaction. Reaction with CO2 oxidized the zinc, enhancing its stability over the copper substrates.

Hypertriglyceridemic waist and arterial hypertension in adults: a systematic review and meta-analysis / Cintura hipertrigliceridémica e hipertensión arterial en adultos: una revisión sistemática y metaanálisis

Objective: To develop a systematic review and meta-analysis to determine the association between hypertriglyceridemic waist (CHTG) and arterial hypertension (HBP) in adults. Materials: The present study is a systematic review (SR) with meta-analysis of analytical cross-sectional observational studies. Search strategies will be used in different databases, which will be Pubmed, SCOPUS, Web of Science, Embase. The qualitative analysis was presented in a table with the characteristics of each study. For quantitative analysis, random-effects meta-analysis was performed due to the heterogeneity of the studies. These variables were compared using Odds Ratios (OR) as a measure of association with their corresponding 95% confidence interval. Results: Five studies were included for statistical analysis. Overall, a statistically significant association was found between both variables (OR: 1.36; 95% CI 1.07 to 1.71). In turn, there was a high heterogeneity (I squared 92%). Conclusions: This SR found that CHTG is associated with the presence of hypertension. However, given the few studies found, it is recommended to carry out more primary studies with a prospective design before carrying out a next SR on the subject, and with standardized cut-off points to make a more homogeneous comparability.

Objetivo: Desarrollar una revisión sistemática y metaanálisis para determinar la asociación entre la cintura hipertrigliceridémica (CHTG) e hipertensión arterial (HTA) en adultos. Materiales: El presente estudio es una revisión sistemática (RS) con metanálisis de estudios observacionales de corte transversal analítico. Se utilizarán estrategias de búsqueda en diferentes bases de datos las cuales serán Pubmed, SCOPUS, Web of Science, Embase. El análisis cualitativo fue presentado en una tabla con las características de cada estudio. Para el análisis cuantitativo, se realizó el metaanálisis de efectos aleatorios debido a la heterogeneidad de los estudios. Dichas variables fueron comparadas usando como medida de asociación Odds Ratios (OR) con su correspondiente intervalo de confianza al 95%. Resultados: Se incluyeron 5 estudios para el análisis estadístico. De manera global, se encontró asociación estadísticamente significativa entre ambas variables (OR: 1,36; IC 95% 1,07 a 1,71). A su vez, se presentó una alta heterogeneidad (I cuadrado del 92%). Conclusiones: La presente RS encontró que la CHTG está asociado con la presencia de HTA. No obstante, dado los pocos estudios encontrados, se recomienda la realización de más estudios primarios con un diseño prospectivo antes de la realización de una siguiente RS del tema, y con puntos de corte estandarizados para hacer una comparabilidad más homogénea.

Metástasis cerebrales en cáncer de pulmón de células no pequeñas con mutación EGFR / Cerebral metastases in lung cancer of non-small cells with egfr mutation

El cáncer de pulmón es uno de los tumores que tienen la capacidad de metastatizarse en el cerebro y tienen la capacidad de penetrar la barrera hematoencefálica, la clínica es variada dependiendo del sitio afectado, así como los riesgos asociados de convulsión. Por lo tanto, la elección del tratamiento es compleja, considerando el primario, el número de metástasis y los sitios afectados. La radioterapia ha sido durante mucho tiempo la elección de los pacientes que no son candidatos a la cirugía, La presencia de mutaciones han permitido brindar terapias dirigidas como los inhibidores tirosin kinasas que penetran la barrera hematoencefálica y han sido clave para el manejo terapéutico.

Lung cancer is one of the tumors that have the ability to metastasize in the brain and have the ability to penetrate the blood-brain barrier, the clinic is varied depending on the affected site, as well as the associated risks of seizure. Therefore, the choice of treatment is complex, considering the primary, the number of metastases and the affected sites. Radiotherapy has long been the choice of patients who are not candidates for surgery. The presence of mutations have allowed targeted therapies such as tyrosine kinase inhibitors that penetrate the blood-brain barrier and have been key to therapeutic management.

Efecto antitumoral in vitro del aceite esencial de Piper aduncum L. (matico) y su toxicidad oral en ratones / Piper aduncum L. (matico) essential oil in vitro antitumoral effect and oral toxicity in mice

Introducción: Piper aduncum (matico) es una especie utilizada por sus propiedades medicinales en desórdenes gastrointestinales y genitourinarios. Objetivos: Evaluar el efecto antitumoral del aceite esencial de Piper aduncum (matico) in vitro en siete líneas celulares tumorales humanas y determinar la toxicidad oral en ratones. Diseño: Experimental. Institución: Facultad de Medicina, Universidad Nacional Mayor de San Marcos, Lima, Perú. Material biológico: Líneas celulares tumorales humanas H460, DU-145, ME-180, K562, HT-29, MCF 7, M14, K562; fibroblastos normales de ratón 3T3 y ratones albinos machos Balb/C53. Intervenciones: Las líneas celulares fueron expuestas a cuatro concentraciones del aceite esencial de P. aduncum y 5-fluorouracilo (5-FU). Para la toxicidad oral se utilizó ratones albinos machos Balb C/53 de 40 días post destete, a cinco dosis de tratamiento, evaluándose el número de muertes en cada dosis. Principales medidas de los resultados: Porcentaje de inhibición del crecimiento celular (IC50), dosis letal 50 (DL50). Resultados: El aceite esencial mostró IC50 mayor a 250 ug/mL para las líneas celulares M-14 (r = -0,99; p < 0,01), DU-145 (r = 0,99; p < 0,01), ME-180 (r = -0,99; p < 0,01). Para líneas celulares tumorales H460 (r = -0,99; p < 0,01), MCF-7 (r = -0,99; p < 0,01), K562 (r = -0,99; p < 0,01), HT-29 (r = -0,99; p < 0,01), los niveles de IC50 estuvieron entre 20 ug/mL y 250 ug/mL. DL50 > 2 000 mg/kg. Conclusiones: El aceite esencial de P. aduncum no presentó efecto antitumoral in vitro para las siete líneas celulares tumorales humanas y no fue tóxico.

Introduction: Piper aduncum (matìco) is a medicinal plant used for gastrointestinal and genitourinary disorders. Objectives: To determine the in vitro antitumoral effect of Piper aduncum (matico) essential oil on seven human tumoral cell lines and its oral toxicity in mice. Design: Experimental. Setting: Faculty of Medicine, Universidad Nacional Mayor de San Marcos, Lima, Peru. Biologic material: Human tumoral cell lines HT-29, H-460, MCF-7, M-14, ME-180, DU-145, K-562; and 3T3 fibroblasts and male 40 days post weaning Balb C/53 mice. Interventions: The cell lines HT-29, H-460, MCF-7, M-14, ME-180, DU-145, K-562, and 3T3 were exposed to four different concentrations of Piper aduncum essential oil, and to different 5-fluorouracil concentrations used as a positive control. Cell lines growth inhibition (IC50) was determined using linear regression analysis and DL50 by the number of deaths with each dose. Main outcome measures: Antitumor effect. Results: Piper aduncum essential oil showed cytotoxic activity at IC50 levels > 250 ug/mL on cell lines M-14 (r = -0.99; p < 0.01), DU-145 (r = -0.99; p < 0.01), ME-180 (r = -0.99; p < 0.01). IC50 was between 20 ug/mL and 250 ug/mL on cell lines H-460 (r = -0.99; p < 0.01), MCF-7, (r = -0.99; p < 0.01), K562 (r = -0.99; p < 0.01), HT-29 (r = -0.99; p < 0.01). DL50 was > 2 000 mg/kg. Conclusions: P. aduncum essential oil did not show antitumoral effect on seven human tumoral cell lines and it was non toxic.