Catequinas del té verde: efectos antigenotóxicos y genotóxicos. Revisión sistemática / Green tea catechins: antigenotoxic and genotoxic effects. Systematic review

Las catequinas del té verde (Camellia sinensis) (CTV) presentan efectos benéficos para la salud asociados a su potencial antioxidante. Por otra parte, el estrés oxidante es una de las vías de inducción de daño genotóxico. De ahí que, en la presente revisión se realizó un análisis de los efectos antigenotóxicos y genotóxicos de las CTV, haciendo énfasis en las vías implicadas en estos procesos y sus efectos en la salud. Se realizó una revisión de artículos indexados en las bases de datos de PubMed® y Science Direct® (2021) con las palabras clave "green tea" y "green tea catechins". Se delimitaron los estudios utilizando los operadores booleanos "AND", "OR" y "NOT" ("antigenotoxic", "genotoxic", "antioxidant" y "prooxidant"). En su mayoría se consideraron las publicaciones del 2016 al 2021. Se observó que los efectos benéficos en la salud de las CTV están relacionados con: a) su actividad antioxidante mediante la captura, inhibición y prevención de la formación de las especies reactivas de oxígeno; b) la regulación del sistema antioxidante endógeno; c) la activación de los mecanismos de reparación al contribuir en la eliminación del aducto 8-hidroxi-2'-desoxiguanosina; d) la inducción de apoptosis en células con daño al ADN; y e) la inhibición de la inflamación relacionada con su actividad antiapoptótica. Si bien, en algunos de los estudios se reportaron efectos genotóxicos, estos a su vez contribuyeron en la eliminación de células con daño genético, por lo que, no se puede considerar del todo a la actividad genotóxica de las CTV como perjudiciales para la salud(AU)

The green tea catechins (Camellia sinensis) (CTV) have beneficial effects for health associated with their antioxidant potential. Moreover, oxidative stress is one of the pathways for inducing genotoxic damage. Hence, in this review, an analysis of the antigenotoxic and genotoxic effects of CTV was carried out, emphasizing the pathways involved in these processes and their effects on health. A review of articles indexed in the PubMed® and ScienceDirect® (2021) databases with the keywords "green tea" and "green tea catechins" was carried out. Studies were delimited using the Boolean operators "AND", "OR" and "NOT" ("antigenotoxic", "genotoxic", "antioxidant" and "prooxidant"). For the most part, publications from 2016 to 2021 were considered. It was observed that the beneficial health effects of CTVs are related to: a) their antioxidant activity through the capture, inhibition and prevention of the formation of reactive oxygen species; b) the regulation of the endogenous antioxidant system; c) the activation of the repair mechanisms by contributing to the elimination of the 8-hydroxy-2'-deoxyguanosine adduct; d) the induction of apoptosis in cells with DNA damage; and e) the inhibition of inflammation related to its antiapoptotic activity. Although some of the studies reported genotoxic effects, these in turn contributed to the elimination of cells with genetic damage. Therefore, the genotoxic activity of CTV cannot be considered as harmful to health

In vivo protective effect of cinnamon aqueous extract in carbon tetrachloride-treated male albino rats

The liver as an organ is important for the metabolism of drugs and toxins. However, it is not immune from environmental insults. Exposure of liver cells to carbon tetrachloride (CCl4) results in the generation of tricholoromethyl radicals, which induce liver toxicity. This study aims at investigating the ameliorative effect of the cinnamon aqueous extract (CAE) against CCl4-induced hepatotoxicity in male albino rats. Hepatotoxicity was induced in rats through the intraperitoneal administration of 0.5 mL kg-1body weight of CCl4. The analyses of the results obtained showed significant reduction in the levels of serum biochemical markers for 400 and 600 mg kg-1bw of CAE protected rats as compared with CCl4group. In addition, CAE administration reversed liver tissue damaged via increased antioxidants markers. Histopathological examination of CAE treatment on rats showed improved changes to the liver damage caused by CCl4 with no evidence of steatosis and inflammation. This result hence suggests that CAE has marked hepatoprotective and healing activities against CCl4-induced liver damage and could serve as a suitable candidate in drug discovery for the treatment of liver toxicity.

Use of erythrocytes in cytotoxicity and toxicity assays of medicinal plant extracts: analysis of their application and bibliometric study / Utilización de eritrocitos en ensayos de citotoxicidad y toxidez de extractos de plantas medicinales: análisis de su aplicación y estudio bibliométrico

Plant species have been used for therapeutic purposes since ancient times and are still in use today since these products represent a source of raw material for the production of phytotherapeutic formulations. Screening and investigation of plants with pharmacological potential require the evaluation of characteristics related to their action, efficacy and safety in different steps. Among these steps, pre- clinical trials are used to evaluate the properties of the test product in in vitro experiments, such as cytotoxicity assays. Within this context, this study consists of a bibliometric analysis of some in vitro cytotoxicity and toxicity assays in erythrocytes used during bioprospecting of medicinal plants. The results demonstrated the wide application of erythrocytes to evaluate the biological effects of medicinal plant extracts. The methods were found to be valid and effective for the preliminary investigation of the in vitro cytotoxicity and toxicity of plant products.

El uso de especies vegetales para fines terapéuticos es una práctica histórica y todavía bastante actual, ya que estos productos pueden representar una fuente de materia prima para la producción de formulaciones fitoterápicas. En investigación de plantas con potencial farmacológico requiere la evaluación de su acción, eficacia y seguridad, a través de diferentes etapas. Entre estas, en los ensayos preclínicos se evalúan las propiedades del producto-prueba en experimentos in vitro, tales como ensayos de citotoxicidad, entre otros. En este aspecto, el presente estudio consiste en un análisis bibliométrico acerca de algunas pruebas de citotoxicidad y toxicidad in vitro en eritrocitos realizados en los ensayos de bioprospección de plantas medicinales. Los resultados evidencian la amplia utilización de eritrocitos para la evaluación de los efectos biológicos de extractos de plantas medicinales, apuntándolos como métodos válidos y eficaces para la investigación preliminar de la citotoxicidad y toxicidad in vitro de productos vegetales.

Assessment of the antibacterial, cytotoxic and antioxidant activities of Morus nigra L. (Moraceae) / Avaliação das atividades antibacteriana, citotóxica e antioxidante de Morus nigra L. (Moraceae)

Abstract This study was carried out to assess the antibacterial, cytotoxic and antioxidant activities of extracts of Morus nigra L. HPLC was used to determine the fingerprint chromatogram of the crude ethanolic extract (Mn-EtOH). The antibacterial effect was assessed through the method of microdilution. The cytotoxicity was tested against human tumour cell lines using the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay. The total phenolic and flavonoid contents were also assessed through the Folin-Ciocalteu and aluminum chloride methods, respectively. Antioxidant activities of the extracts were evaluated by using 2,2-diphenyl-1-picrylhydrazil (DPPH) radical scavenging and β-carotene-linoleic acid bleaching methods. The presence of phenolic compounds in Mn-EtOH was confirmed using HPLC. The extracts showed activity against most microorganisms tested. The extracts did not show any expressive antiproliferative effect in the assessment of cytotoxicity. The most significant total phenolic content was 153.00 ± 11.34 mg of gallic acid equivalent/g to the ethyl acetate extract (AcOEt). The total flavonoid content was 292.50 ± 70.34 mg of catechin equivalent/g to the AcOEt extract, which presented the best antioxidant activity (IC50 50.40 ± 1.16 μg/mL) for DPPH scavenging. We can conclude that this species shows strong antibacterial and antioxidant activities, as well as weak cytotoxic effects.

Resumo Este estudo foi realizado para avaliar as atividades antibacteriana, citotóxica e antioxidante de extratos de Morus nigra L. HPLC foi utilizado para determinar o perfil de compostos fenólicos do extrato etanólico bruto (Mn-EtOH). O efeito antibacteriano foi avaliado através do método de microdiluição. A citotoxicidade foi testada contra linhagens celulares de tumores humanos utilizando o ensaio do brometo de 3-(4,5-dimetil-2-tiazolil)-2,5-difenil-2H-tetrazólio (MTT). O conteúdo total de compostos fenólicos e flavonoides também foi avaliado por meio dos métodos de Folin-Ciocalteu e cloreto de alumínio, respectivamente. A atividade antioxidante dos extratos foi avaliada por meio do sequestro do radical livre 2,2-difenil-1-picrilhidrazil (DPPH) e co-oxidação do sistema β-caroteno-ácido linoleico. A presença de compostos fenólicos em Mn-EtOH foi confirmada utilizando HPLC. Os extratos mostraram atividade contra a maioria dos microrganismos testados. Os extratos não mostraram qualquer efeito antiproliferativo expressivo na avaliação da citotoxicidade. O conteúdo fenólico total mais significativo foi de 153,00 ± 11,34 mg de equivalente de ácido gálico/g para o extrato acetato de etila (AcOEt). O conteúdo de flavonoides totais foi de 292,50 ± 70,34 mg de equivalente de catequina/g para o extrato AcOEt, que apresentou a melhor atividade antioxidante (IC50 50,40 ± 1,16 mg/mL) para o sequestro do DPPH. Podemos concluir que esta espécie apresenta forte atividade antibacteriana e antioxidante, bem como fraca atividade citotóxica.

Sida tuberculata (Malvaceae): a study based on development of extractive system and in silico and in vitro properties

Sida tuberculata (Malvaceae) is a medicinal plant traditionally used in Brazil as an antimicrobial and anti-inflammatory agent. Here, we aimed to investigate the different extractive techniques on phytochemical parameters, as well as to evaluate the toxicity and antioxidant capacity of S. tuberculata extracts using in silico and in vitro models. Therefore, in order to determine the dry residue content and the main compound 20-hydroxyecdysone (20E) concentration, extracts from leaves and roots were prepared testing ethanol and water in different proportions. Extracts were then assessed by Artemia salina lethality test, and toxicity prediction of 20E was estimated. Antioxidant activity was performed by DPPH and ABTS radical scavenger assays, ferric reducing power assay, nitrogen derivative scavenger, deoxyribose degradation, and TBARS assays. HPLC evaluation detected 20E as main compound in leaves and roots. Percolation method showed the highest concentrations of 20E (0.134 and 0.096 mg/mL of extract for leaves and roots, respectively). All crude extracts presented low toxic potential on A. salina (LD50 >1000 µg/mL). The computational evaluation of 20E showed a low toxicity prediction. For in vitro antioxidant tests, hydroethanolic extracts of leaves were most effective compared to roots. In addition, hydroethanolic extracts presented a higher IC50 antioxidant than aqueous extracts. TBARS formation was prevented by leaves hydroethanolic extract from 0.015 and 0.03 mg/mL and for roots from 0.03 and 0.3 mg/mL on egg yolk and rat tissue, respectively (P<0.05). These findings suggest that S. tuberculata extracts are a considerable source of ecdysteroids and possesses a significant antioxidant property with low toxic potential.

Toxicidade do peróxido de carbamida 16% adicionado de nanopartículas de hidroxiapatita / Carbamide peroxide toxicity added 16% hydroxyapatite nanoparticles

O clareamento dental é um dos tratamentos mais realizados nos consultórios odontológicos a fim de melhorar a aparência do sorriso. O procedimento consiste na aplicação de um gel clareador, a base de peróxido de carbamida ou de hidrogênio, sobre os dentes a serem clareados. A sensibilidade dentária é o efeito adverso mais frequentemente relatado no clareamento dentário e é a principal causa de desmotivação dos pacientes. O mecanismo pelo qual se produz a sensibilidade após clareamento dentário ainda não foi completamente elucidado; no entanto, parece estar associado à rápida difusão dos agentes clareadores através do esmalte e dentina que, devido ao seu grau de citotoxicidade, podem agir agredindo as células pulpares, causando sensibilidade. O objetivo deste estudo foi avaliar a biocompatibilidade de nanopartícula de hidroxiapatita adicionada ao gel clareador peróxido de carbamida 16% com flúor e sem flúor e, para tanto, foram realizados testes de citotoxidade empregando MTT. Como resultados verificou-se que as nanopartículas de hidroxiapatita, quando comparadas aos géis de peróxido de carbamida a 16% com e sem flúor, foram as menos citotóxicas (p< 0.05). As diluições citotóxicas convertidas para 70% das amostras testadas também foram comparadas através do teste de Anova com tukey. Foi possível observar que as partículas de nanoHap quando adicionadas nos géis de clareamento com e sem flúor reduziu significativamento a citotoxidade. Concluímos que o novo material proposto nesta investigação apresenta melhor biocompatibilidade do que o gel sem hidroxiapatita, acompanhado da redução da citotoxidade, tais aspectos sugerem que as nanopartículas de hidroxiapatita podem ter aplicações clínicas futuras em tecidos mineralizados em procedimentos de clareamento dental, contribuindo para a redução da sensibilidade dentária.

The dental bleaching is one of the most procedures performed at dental offices to improve the appearance of the smile. The procedure consists of the application of a bleching gel, based on carbamide peroxide or hydrogen over the teeth to be whitened. Tooth sensibility is the frequently reported adverse effect on tooth whitening and is the leading cause of demotivation by the patients. The mechanism that provides the sensibility after tooth whitening has not already been fully elucidated; however, it appears to be associated with the rapid diffusion of bleaching agents through the enamel and dentin that, because of their degree of cytotoxicity, may act attacking pulp cells, causing the sensibility. The aim of this study was to evaluate the biocompatibility of hydroxyapatite nanoparticles added to whitening gel of 16% carbamide peroxide with and without fluoride and, therefore, cytotoxicity tests were performed using MTT. As a result, it was found that the hydroxyapatite nanoparticles, compared to the gels of 16 % carbamide peroxide with and without fluoride, were less cytotoxic (p <0.05). Cytotoxic dilutions converted to 70 % of the tested samples were compared using ANOVA test with Tukey. We concluded that the new material proposed in this research has a better biocompatibility in comparison with the gel without hydroxyapatite, followed by a reduction of cytotoxicity. These aspects suggest that the hydroxyapatite nanoparticles may have clinical future applications in mineralized tissues when dental bleaching procedures are performed, contributing to the reduction of tooth sensitivity. We conclude that the new material proposed in this research has a better biocompatibility of the gel without hydroxyapatite, accompanied by a reduction of cytotoxicity, these aspects suggest that the hydroxyapatite nanoparticles may have future clinical applications in mineralized tissues in dental bleaching procedures, contributing to a reduction tooth sensitivity.

Antioxidant and genotoxic properties of Maytenus dasyclada: a comparative study in relation to Maytenus reference species / Propriedades antioxidantes e genotóxicas de Maytenus dasyclada: um estudo comparativo em relação às espécies de referência de Maytenus

In these work the in vitro antioxidant activity and the in vivo genotoxicity of M. dasyclada was compared to the reference species M. aquifolium and M. ilicifolia. M. dasyclada showed in vitro antioxidant activity comparable to M. aquifolium but lower than M. ilicifolia, being that a inverse Pearson correlation between DPPH IC50 values and total phenolic content was detected (–0.932). The carbonyl content of M. dasyclada and M. aquifolium extracts promoted a similar increase in protein oxidation in vivo, while M. ilicifolia no altered the carbonyl levels. The comet assay demonstrated that the three analyzed species promoted a low and similar level of genotoxicity; which is compatible with DNA damage induced by other medicinal plants and is partially recovered by a co-treatment with vitamin C. The data showed M. dasyclada as antioxidant activity in vitro, and that its genotoxic and pro-oxidant effects in vivo are comparable to the Maytenus reference species.

No presente trabalho a atividade antioxidante in vitro e a genotoxicidade in vivo de M. dasyclada foi comparada com as espécies de referência M.aquifolium e M. ilicifolia. M. dasyclada mostrou atividade antioxidante in vitro comparável a de M. aquifolium mas inferior a M. ilicifolia, sendo que foi detectada uma correlação de Pearson inversa entre os valores de IC50 por DPPH e o conteúdo fenólico total (–0,932). Em relação ao teor de carbonila, os extratos de M. dasyclada e M. aquifolium promoveram um aumento semelhante na oxidação das proteínas in vivo, ao passo que Maytenus ilicifolia não alterou os níveis de carbonila. O ensaio do cometa demonstrou que as três espécies analisadas promoveram um nível baixo e semelhante de genotoxicidade, o que é compatível com os danos no DNA induzidos por outras plantas medicinais e é parcialmente recuperada por um co-tratamento com a vitamina C. Os dados mostraram M. dasyclada com atividade antioxidante in vitro, e que os seus efeitos genotóxicos e pró-oxidantes in vivo são comparáveis às espécies de referência de Maytenus.

Análisis de riesgos de la brucelosis en el estado de Tlaxcala / Risk analysis of brucelosis in the state of Tlaxcala

Objetivo. Identificar los riesgos de la brucelosis en el estado de Tlaxcala, México. Material y métodos. Se realizó un diagnóstico de tipo social en los municipios de Huamantla, Ixtenco y Teacalco, localizadas en la región oriente del estado. Se determinó la seroprevalencia de brucelosis en cabras y humanos. Resultados. El 46.9% de productores conoce los programas de la vacunación contra brucelosis; 19.7% aplica vacuna y 80.3% no aplica vacuna. Huamantla presentó la mayor seroprevalencia de brucelosis animal en 66.8 por ciento. San José Teacalco distribuye y comercializa quesos no pasteurizados en una distancia mayor de 270 km, lo que amplía los riesgos de contagio por brucelosis. Ixtenco registró la mayor prevalencia de brucelosis en humanos con 1.51 por ciento. Conclusión. Los municipios estudiados presentan riesgos de contagio y propagación de la brucelosis.

Objective. To identify the risk of brucellosis in the state of Tlaxcala, Mexico. Materials and methods. A diagnosis of social type was conducted in the municipalities of Huamantla, Ixtenco and Teacalco, located in the eastern region of the state. The seroprevalence of brucellosis in goats and humans was determined. Results. 46.9% of producers know the programs of vaccination against brucellosis; 19.7% apply the vaccine and 80.3% do not apply the vaccine. Huamantla had the highest seroprevalence of animal brucellosis in 66.8%; San Jose Teacalco distributes unpasteurized cheeses to a distance of 270 km, increasing the risk of infection with brucellosis. Ixtenco recorded the highest prevalence of brucellosis in humans, with 1.51%. Conclusion. The municipalities studied present risks of infection and spread of brucellosis.

Pulmonary phospholipid changes induced by butylated hydroxy toluene, an antioxidant, in rats.

Butylated hydroxy toluene (BHT), 800 mg/kg body weight, dissolved in corn oil and administered (ip) in a single injection to male rats, damaged the lung as indicated by an increase in lavage ACE, protein and LDH and caused a significant increase in phospholipid, particularly, phosphatidyl choline (PC) in lung lavage and extracellular surfactant. The plasma lecithin cholesterol acyl transferase (LCAT) activity was inhibited leading to an increase in serum phospholipids and phosphatidyl choline. The results indicate that BHT-induced lung phospholipidosis may be attributed to an increase in surfactant phospholipids and/or due to the leakage of plasma phospholipids through damaged capillary membrane.

Mecanismos de neurotoxicidad de la 1-Metil-4-Fenil-1,2,3, 6-Tetrahidropiridina (MPTP) / Mechanisms of the neurotoxicity of 1 Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)

La neurotoxina 1-metil-4-fenil-1,2,3,6-tetrahidropiridina (MPTP) produce toxicidad de las neuronas dopaminérgicas de la vía nigroestriatal, como en la enfermedad de Parkinson idiopática. El mecanismo de daño celular causado por esta toxina se desconoce, sin embargo, se han propuesto una serie de hipótesis: el daño a la mitocondria y la fuerza oxidativa. El 1-metil-4-fenilpiridino (MPP+), el mayor metabolito activo de la MPTP es captado por la mitocondria, en donde se acumula e inhibe la oxidación de sustratos unidos al NADH de la mitocondria causando una disminución del ATP. Esto sugiere que la toxicidad del MPP+ puede atribuirse a la inhibición de las funciones de la mitocondria. Sin embargo, esta disminución ha sido observada durante pocas horas. Esto sugiere un segundo mecanismo de daño a las neuronas que pueda explicar los efectos a largo plazo del MPP+. La MPTP genera la formación de radicales libres del oxígeno así como también reduce las defensas antioxidantes endógenas y el glutatión para combatir los radicales libres. La toxicidad de la MPTP es disminuida por una variedad de antioxidantes y por el ácido ascórbico que pueden reducir los cambios bioquímicos producidos por el tratamiento con la MPTP. Esos resultados sugieren que la fuerza oxidativa puede producir daño a las neuronas después de la administración de la MPTP.