ABSTRACT
The ultraviolet (UV) component of sunlight can damage DNA. Although most solar UV is absorbed by the ozone layer, wavelengths > 300 nm (UVA and UVB bands) can reach the Earth's surface. It is essential to understand the genotoxic effects of UV light, particularly in natural environments. Caulobacter crescentus, a bacterium widely employed as a model for cell cycle studies, was selected for this study. Strains proficient and deficient in DNA repair (uvrA-) were used to concurrently investigate three genotoxic endpoints: cytotoxicity, SOS induction, and gene mutation, using colony-formation, the SOS chromotest, and RifR mutagenesis, respectively. Our findings underscore the distinct impacts of individual UV bands and the full spectrum of sunlight itself in C. crescentus. UVC light was highly genotoxic, especially for the repair-deficient strain. A UVB dose equivalent to 20 min sunlight exposure also affected the cells. UVA exposure caused a significant response only at high doses, likely due to activation of photorepair. Exposure to solar irradiation resulted in reduced levels of SOS induction, possibly due to decreased cell survival. However, mutagenicity is increased, particularly in uvrA- deficient cells.
Subject(s)
Caulobacter crescentus , Ultraviolet Rays , Ultraviolet Rays/adverse effects , Caulobacter crescentus/genetics , DNA Damage , DNA Repair , MutationABSTRACT
CONTEXT: Phytocompounds xanthatin and 8-epi-xanthatin, obtained from Xanthium chinese Mill, showed antitumoral activity in vitro related to the microtubules destabilizing properties of these phytocompounds. Five binding sites for microtubule destabilizing agents have been characterized on tubulin by high-resolution X-ray crystallography: vinca domain, colchicine, pironetin, maytansine site, and more recently, the seventh site. This work aims to develop a comprehensive computational strategy to understand and eventually predict the interaction between xanthatin and 8-epi-xanthatin with the destabilizing-antimitotic binding domain of the tubulin heterodimer. In addition, we propose a putative binding site for these phytocompounds into the microtubule destabilizing binding sites on the tubulin heterodimer. Xanthanolides showed higher stability in the colchicine and pironetin binding sites, whit a greater affinity for the former. In addition, we found that xanthanolides and non-classical colchicine binding site inhibitors share a high structural similarity. METHODS: The 3D structures for xanthatin and 8-epi-xanthatin were obtained using DFT with the hybrid functional B3LYP and the base 6-31G (d,p), implemented in Gaussian 09. The 3D coordinates for tubulin proteins were downloaded from PDB. The complexes tubulin-xanthanolides were predicted using a Monte-Carlo iterated search combined with the BFGS gradient-based optimizer implemented in the AutoDock Vina. The xanthanolides-tubulin complexes were energy minimized by molecular dynamics simulations at vacuum, and their stabilities were evaluated by solvated molecular dynamics simulations during 100 ns. All molecular dynamics simulations were performed using the conjugate gradient method implemented in NAMD2 and CHARMM36 forcefield.
Subject(s)
Antineoplastic Agents , Colchicine , Colchicine/pharmacology , Colchicine/chemistry , Tubulin/metabolism , Furans/pharmacology , Binding Sites , Microtubules , Antineoplastic Agents/pharmacologyABSTRACT
Sunlight ultraviolet (UV) radiation constitutes an important environmental genotoxic agent that organisms are exposed to, as it can damage DNA directly, generating pyrimidine dimers, and indirectly, generating oxidized bases and single-strand breaks (SSBs). These lesions can lead to mutations, triggering skin and eye disorders, including carcinogenesis and photoaging. Stratospheric ozone layer depletion, particularly in the Antarctic continent, predicts an uncertain scenario of UV incidence on the Earth in the next decades. This research evaluates the DNA damage caused by environmental exposure to late spring sunlight in the Antarctic Peninsula, where the ozone layer hole is more pronounced. These experiments were performed at the Brazilian Comandante Ferraz Antarctic Station, at King's George Island, South Shetlands Islands. For comparison, tropical regions were also analyzed. Samples of plasmid DNA were exposed to sunlight. Cyclobutane pyrimidine dimers (CPDs), oxidized base damage and SSBs were detected using specific enzymes. In addition, an immunological approach was used to detect CPDs. The results reveal high levels of DNA damage induced by exposure under the Antarctic sunlight, inversely correlated with ozone layer thickness, confirming the high impact of ozone layer depletion on the DNA damaging action of sunlight in Antarctica.
Subject(s)
DNA Damage , Seasons , Sunlight , Antarctic Regions , DNA Repair , Ozone DepletionABSTRACT
Phyllanthus orbicularis (Phyllanthaceae) is an endemic evergreen tropical plant of Cuba that grows in the western part of the island and is used in traditional medicine as an infusion. The aqueous extract of this plant presents a wide range of pharmacological activitiessuch as antimutagenic, antioxidant and antiviral effects. Given the many beneficial effects and the great interest in the development of new pharmacological products from natural sources, the aim of this work was to investigate the phytochemistry of this species and to elucidate the structure of the main bioactive principles. Besides the presence of several known polyphenols, the major constituent was hitherto not described. The chemical structure of this compound, here named Fideloside, was elucidated by means of HR-ESIMS/MSn, 1D/2D NMR, FT-IR, and ECD as (2R,3R)-(-)-3',4',5,7-tetrahydroxydihydroflavonol-8-C-ß-D-glucopyranoside. The compound, as well as the plant aqueous preparations, showed promising bioactive properties, i.e., anti-inflammatory capacity in human explanted monocytes, corroborating future pharmacological use for this new natural C-glycosyl flavanonol.
Subject(s)
Phyllanthus/chemistry , Phytochemicals/chemistry , Plant Extracts/chemistry , Plants, Medicinal/chemistry , Chromatography, High Pressure Liquid , Cytokines/metabolism , Flavonoids/chemistry , Flavonoids/pharmacology , Humans , Models, Molecular , Molecular Structure , Monocytes/drug effects , Monocytes/metabolism , Phytochemicals/pharmacology , Plant Extracts/pharmacology , Spectrum AnalysisABSTRACT
BACKGROUND: Colorectal cancer is one of the most common malignancies worldwide and is associated with high mortality rates. We previously reported that Xanthium strumarium L. induces mitotic arrest in proliferating cells, a process mediated by xanthatins. HYPOTHESIS/AIM: The aim of this work is to study if xanthatins, isolated from X. strumarium total extract, affect the proliferative capacity of CT26WT colon cancer cells and, in consequence, if tumor growth and proliferation of (lung) metastatic sites can also be arrested in vivo. STUDY DESIGN: This study consisted of both in vitro and in vivo experiments involving the CT26WT cell line and a subcutaneous mouse model of colon cancer. In vitro cell cycle progression, in vivo tumoral growth and anti-metastatic activity were analyzed to investigate whether xanthatins of X. strumarium induce mitotic arrest in proliferating colorectal carcinoma. RESULTS: Our in vitro results show that X. strumarium, mediated by xanthatins, induces G2/M arrest and impair anaphase entrance. This leads to a significant induction of apoptotic and necrotic in CT26WT cells, demonstrating their significant anti-proliferative activity through interfering with the mitotic apparatus. Furthermore, our in vivoresults reveal that X. strumarium inhibits both tumor growth and metastasis progression. CONCLUSION: X. strumarium antitumor activities are mainly mediated by xanthatins through inhibition of tumor growth and metastasis, inducing mitotic arrest and apoptosis in colon carcinoma cells. These findings further confirm the therapeutic potential of X. strumarium in colorectal cancer.
Subject(s)
Antineoplastic Agents, Phytogenic/pharmacology , Colorectal Neoplasms/drug therapy , Furans/pharmacology , Xanthium/chemistry , Animals , Apoptosis/drug effects , Cell Line, Tumor , Cell Proliferation/drug effects , Colonic Neoplasms/drug therapy , Colonic Neoplasms/pathology , Colorectal Neoplasms/pathology , Drug Screening Assays, Antitumor , Male , Mice, Inbred BALB C , Mitosis/drug effects , Plant Extracts/chemistry , Plant Extracts/pharmacologyABSTRACT
One approach to protect the human skin against harmful effects of solar ultraviolet (UV) radiation was to use natural products as photoprotectors. In this work, the extract from specie Phyllanthus orbicularis K was evaluated as a protective agent against the photodamage by UVB, UVA artificial lamps, and environmental sunlight exposure. The plasmid DNA solutions were exposed to radiations using the DNA dosimeter system in the presence of plant extract. The DNA repair enzymes, Escherichia coli Formamidopyrimidine-DNA glycosylase (Fpg) and T4 bacteriophage endonuclease V (T4-endo V), were employed to discriminate oxidized DNA damage and cyclobutane pyrimidine dimers (CPD), respectively. The supercoiled and relaxed forms of DNA were separated through electrophoretic migration in agarose gels. These DNA forms were quantified to determine strand break, representing the types of lesion levels. The results showed that, in the presence of P. orbicularis extract, the CPD and oxidative damage were reduced in irradiated DNA samples. The photoprotective effect of extract was more evident for UVB and sunlight radiation than for UVA. This work documented the UV absorbing properties of P. orbicularis aqueous extract and opened up new vistas in its characterization as protective agent against DNA damage induced by environmental sunlight radiation.
Subject(s)
Antimutagenic Agents/pharmacology , Phyllanthus/chemistry , Plant Extracts/pharmacology , Radiation-Protective Agents/pharmacology , Sunlight/adverse effects , Ultraviolet Rays/adverse effects , DNA/radiation effects , DNA Damage , DNA-Formamidopyrimidine Glycosylase/metabolism , Deoxyribonuclease (Pyrimidine Dimer)/metabolism , Electrophoresis, Agar Gel , Escherichia coli/enzymology , Escherichia coli Proteins/metabolism , Oxidative Stress/drug effects , Oxidative Stress/radiation effects , Plasmids , Pyrimidine Dimers/metabolism , Viral Proteins/metabolismABSTRACT
Environmental exposure to genotoxic agents represents a major health concern for modern society. DNA damage could lead to mutations, which accumulative effect is closely related to degenerative and lethal diseases, such as cancer. Because of their structural and chemical diversity natural products play a fundamental role in pharmaceutical sciences for novel drug discovery. The present review article focuses on pre-clinical studies done with some species from Cuban flora that have been tested with positive antigenotoxic properties against different genotoxins. Special emphasis regarding molecular mechanisms suggested, from antioxidant activity to DNA repair modulation, a critical discussion of the state of art and the perspectives in the use of these plants as a new and promising strategy for genoprotection in the 21st Century are included.
La exposicioÌn ambiental a agentes genotoÌxicos representa un problema de salud significativo en la sociedad actual. El danÌo al ADN puede generar mutaciones, cuyo efecto acumulativo se encuentra estrechamente relacionado con enfermedades degenerativas y letales como el caÌncer. Debido a su diversidad estructural y quiÌmica los productos naturales juegan un papel fundamental en las ciencias farmaceÌuticas en el descubrimiento de nuevas drogas. El presente artiÌculo de revisioÌn puntualiza estudios pre-cliÌnicos realizados con determinadas especies de la flora cubana que han sido estudiadas con una respuesta antioxidante positiva frente a diferentes genotoxinas. Se enfatizan especialmente los mecanismos moleculares sugeridos, desde actividad antioxidante hasta modulacioÌn de la reparacioÌn del ADN, asiÌ como una discusioÌn criÌtica del estado del arte y las perspectivas en el empleo de estas plantas como una estrategia nueva y prometedora para la genoproteccioÌn en el siglo 21.
Subject(s)
DNA Damage/drug effects , Phyllanthus/chemistry , Mangifera/chemistry , Cymbopogon/chemistry , Antioxidants/pharmacology , CubaABSTRACT
Objetivo: Evaluar el efecto protector del extracto acuoso de Cymbopogon citratus (DC) Stapf, ante el daño inducido por las radiaciones UVC. Material y Métodos: Para evaluar si el extracto acuoso de C. citratus era capaz de inducir roturas de cadenas en el ADN, moléculas de plásmido pBluescript SK II fueron tratadas con diferentes concentraciones del extracto (0,01 - 4,0 mg/mL), en los tiempos de exposición: 30, 60 y 90 min. El efecto fotoprotector fue evaluado aplicando el extracto vegetal antes, durante, y después de la irradiación del ADN plasmídico con 200 J/m2 de UVC. La actividad enzimática de T4 endonucleasa V fue empleada para detectar formación de CPDs. Las formas superenrollada y relajada de las moléculas de plásmido fueron separadas electroforéticamente en gel de agarosa. Adicionalmente, se midió la transmitancia del extracto acuoso a la DO de 254 nm. Resultados: Ninguna de las concentraciones evaluadas resultó genotóxica con 30 min de tratamiento. Las concentraciones ≥ 2 mg/mL indujeron roturas de cadenas a los 90 min de incubación. El extracto de C. citratus a concentraciones ≥ 0,5 mg/mL protegió al ADN frente a las radiaciones UVC. Conclusiones: En nuestras condiciones experimentales, el extracto acuoso de C. citratus protege al ADN frente a la genotoxicidad inducida por la luz UVC, previniendo la generación de CPDs, pero no es capaz de eliminarlas una vez formadas
Aim: to evaluate the photoprotective effect of aqueous extract of Cymbopogon citratus (DC) Stapf against UVC-induced damage to ADN. Material and methods: In the experimental procedure, samples of plasmid pBluescript SK II solutions were exposed to C. citratus aqueous extract in 0.01-4.0 mg/mL concentrations during 30, 60 and 90 min. In order to evaluate the photoprotective effect, the vegetal extract was applied before, during and after UVC radiation at 200 J/m2 doses. DNA repair enzymes T4 endonuclease V was employed in order to discriminate CPDs damage. Then, supercoiled and relaxed forms of DNA were separated after electrophoretic migration in agarose gels. Also aqueous extract transmittance was measure at 254 nm OD. Results: None of the concentrations tested were genotoxic in 30 min of exposition. Concentrations ≥ 2 mg/mL induced strand breaks at 90 min of incubation. The C. citratus extract at concentrations ≥ 0.5 mg/ mL protect DNA in front of UVC radiation. Conclusions: In our experimental conditions, C. citratus extract protects DNA from the genotoxicity induced by light UVC, preventing the CPDs generation, but is not able to eliminate DNA damage once formed
Subject(s)
DNA/analysis , Cymbopogon , Cymbopogon/genetics , Cymbopogon/radiation effects , Radiation , Deoxyribonuclease IV (Phage T4-Induced) , Genotoxicity/methods , Pyrimidine Dimers/chemical synthesis , Pyrimidine Dimers/therapeutic use , Plants, MedicinalABSTRACT
ETHNOPHARMACOLOGICAL RELEVANCE: Xanthium strumarium L. is a member of the Asteraceae family popularly used with multiple therapeutic purposes. Whole extracts of this plant have shown anti-mitotic activity in vitro suggesting that some components could induce mitotic arrest in proliferating cells. AIM OF THE SUDY: Aim of the present work was to characterize the anti-mitotic properties of the X. strumarium whole extract and to isolate and purify active molecule(s). MATERIALS AND METHODS: The capacity of the whole extract to inhibit mitotic progression in mammalian cultured cells was investigated to identify its anti-mitotic activity. Isolation of active component(s) was performed using a bioassay-guided multistep separation procedure in which whole extract was submitted to a progressive process of fractionation and fractions were challenged for their anti-mitotic activity. RESULTS: Our results show for the first time that X. strumarium whole extract inhibits assembly of the mitotic spindle and spindle-pole separation, thereby heavily affecting mitosis, impairing the metaphase to anaphase transition and inducing apoptosis. The purification procedure led to a fraction with an anti-mitotic activity comparable to that of the whole extract. Chemical analysis of this fraction showed that its major component was xanthatin. CONCLUSIONS: The present work shows a new activity of X. strumarium extract, i.e. the alteration of the mitotic apparatus in cultured cells that may be responsible for the anti-proliferative activity of the extract. Anti-mitotic activity is shown to be mainly exerted by xanthatin.
Subject(s)
Cell Proliferation/drug effects , Furans/chemistry , Furans/pharmacology , Plant Extracts/chemistry , Plant Extracts/pharmacology , Spindle Apparatus/drug effects , Xanthium/chemistry , Animals , Apoptosis/drug effects , CHO Cells , Cell Line , CricetulusABSTRACT
Xanthium strumarium L. is a member of the Asteraceae commonly used in Cuba, mainly as diuretic. Some toxic properties of this plant have also been reported and, to date, very little is known about its genotoxic properties. The present work aims was to evaluate the potential cytotoxic and genotoxic risk of whole extract from Xanthium strumarium L. whole extract of aerial parts. No positive response was observed in a battery of four Salmonella typhimurium strains, when exposed to concentrations up to 5 mg/plate, with and without mammalian metabolic activation (liver microsomal S9 fraction from Wistar rats). In CHO cells, high concentrations (25-100 µg/mL) revealed significant reduction in cell viability. Results from sister chromatid exchanges, chromosome aberrations, and comet assay showed that X. strumarium extract is genotoxic at the highest concentration used, when clear cytotoxic effects were also observed. On the contrary, no increase in micronuclei frequency in bone marrow cells was observed when the extract was orally administered to mice (100, 500, and 2000 mg/Kg doses). The data presented here constitute the most complete study on the genotoxic potential of X. strumarium L. and show that the extract can induce in vitro DNA damage at cytotoxic concentrations.
Subject(s)
DNA Damage/drug effects , Micronuclei, Chromosome-Defective/drug effects , Plant Extracts/administration & dosage , Animals , CHO Cells , Cricetulus , Mice , Plant Extracts/chemistry , Rats , Salmonella typhimurium/drug effects , Xanthium/chemistryABSTRACT
CONTEXT: One approach to protect human skin against the dangerous effects of solar ultraviolet (UV) irradiation is the use of natural products, such as photoprotectors. Phyllanthus orbicularis Kunth (Euphorbiaceae) is a Cuban endemic plant used in popular medicine. Its antigenotoxicity effect against some harmful agents has been investigated. However, the effect in ultraviolet B (UVB)-irradiated human cells has not been previously assessed. OBJECTIVE: The protective effect of a P. orbicularis extract against UVB light-induced damage in human cells was evaluated. MATERIALS AND METHODS: DNA repair proficient (MRC5-SV) and deficient (XP4PA, complementation group XPC) cell-lines were used. Damaging effects of UVB light were evaluated by clonogenic assay and apoptosis induction by flow cytometry techniques. The extent of DNA repair itself was determined by the removal of cyclobutane pyrimidine dimers (CPDs). The CPDs were detected and quantified by slot-blot assay. RESULTS: Treatment of UVB-irradiated MRC5-SV cells with P. orbicularis extract increased the percentage of colony-forming cells from 36.03 ± 3.59 and 4.42 ± 1.45 to 53.14 ± 8.8 and 14.52 ± 1.97, for 400 and 600 J/m(2), respectively. A decrease in apoptotic cell population was observed in cells maintained within the extract. The P. orbicularis extract enhanced the removal of CPD from genomic DNA. The CPDs remaining were found to be about 27.7 and 1.1%, while with plant extract, treatment these values decreased to 16.1 and 0.2%, for 3 and 24 h, respectively. DISCUSSION AND CONCLUSION: P. orbicularis aqueous extract protects human cells against UVB damage. This protective effect is through the modulation of DNA repair effectiveness.
Subject(s)
DNA Repair/drug effects , Phyllanthus/chemistry , Plant Extracts/pharmacology , Ultraviolet Rays/adverse effects , Apoptosis/drug effects , Apoptosis/radiation effects , Cell Line , Colony-Forming Units Assay , Cuba , DNA Repair/radiation effects , Flow Cytometry , Humans , Pyrimidine Dimers/metabolism , Time FactorsABSTRACT
The main objective of anti-carcinogenic chemotherapy is to stop uncontrolled cellular proliferation. This has prompted us to begin a systematic survey of new effective inhibitors with ability to react with cytoskeletal components and arrest living, dividing cells. Even for traditional populations herbs-consuming, encouraging the use of species with chemopreventive actions could be helpful as part of life expectancy improvement strategies. Herbal products have significantly lower costs, exhibit little or no toxicity during long-term oral administration and are relatively available at large scale. Current work involved the screening of 85 extracts from Cuban medicinal plants, selected on the basis of traditional use, ethnobotanics and pharmacological information (antiparasitic, antitumour, abortive, etc.). Antitubulinic activity in the hydroalcoholics extracts was evaluated by using a modified version of the conventional turbidity assay of tubulin assembly/ disassembly. The activity limits of the news isolated antitubulin agents were thoroughly investigated. According to the presented results, the extracts displaying the highest antitubulinic activity were Tamarindus indica L., Lawsonia inermes L and Xanthium strumarium L.
Detener la proliferación celular es el principal propósito de la quimioterapia anticarcinogénica. Para ello se ha realizado una búsqueda a partir de fuentes naturales de nuevos inhibidores efectivos que reaccionen con los componentes del citoesqueleto y puedan detener la división celular. En poblaciones que tradicionalmente utilizan plantas medicinales se estimula el uso de aquellas especies con acción quimiopreventivas como parte de una estrategia que contribuya a la calidad de vida. Los productos herbarios tienen costos significativamente más bajos, exhiben poca o ninguna toxicidad durante la administración oral a largo plazo y están al alcance de todos. Nuestro trabajo consistió en realizar un tamizaje de 85 extractos de plantas medicinales cubanas seleccionadas en base al uso tradicional, en las encuestas etnobotánicas e información farmacológica (actividad antiparasitaria, antitumoral, abortiva, etc). La actividad antitubulínica fue evaluada mediante una versión modificada del ensayo turbimétrico del ensamblaje/desensamblaje de la tubulina. Se determinó la actividad límite de los nuevos agentes antitubulínicos siendo los extractos de Tamarindus indica L., Lawsonia inermes L and Xanthium strumarium L. los de mejor actividad antitubulínica según las condiciones ensayadas.
Subject(s)
Antimitotic Agents/pharmacology , Plant Extracts/pharmacology , Plants/chemistry , Antineoplastic Agents/pharmacology , Cuba , Flora , Lawsonia Plant/chemistry , Microtubules , Plant Preparations/pharmacology , Tamarindus/chemistry , Xanthium/chemistryABSTRACT
Punica granatum L. (Punicaceae) whole fruit extracts, have been used in Cuban traditional medicine as an effective drug for the treatment of respiratory diseases. This species showed interesting anti-viral activity, e.g. aqueous or hydroalcoholic extracts of whole fruits have proved highly active against the influenza virus. However, some toxic properties of this extract have also been reported and, to date, very little is known about its genotoxic properties. In the present study, the genotoxicity of a Punica granatum (pomegranate) whole fruit extract was assessed using different in vitro and in vivo assays that detect DNA damage at different expression levels. Results from reversion and gene-conversion test in microorganisms, sister chromatid exchanges, micronuclei and sperm-shape abnormality assays in mice, clearly showed that the hydroalcoholic extract of P. granatum whole fruits is genotoxic when tested both in vitro and in vivo.
Subject(s)
Lythraceae/chemistry , Mutagens/toxicity , Plant Extracts/toxicity , Animals , CHO Cells , Chromosome Aberrations/drug effects , Cricetinae , Cricetulus , Cuba , Female , Fruit , Male , Medicine, Traditional , Mice , Mice, Inbred BALB C , Mutagenicity Tests , Mutagens/isolation & purification , Sister Chromatid Exchange/drug effects , Spermatozoa/drug effectsABSTRACT
PURPOSE: The aim of this work is to investigate the usefulness of a modified protocol of the SOS Chromotest to detect antigenotoxicity activities against gamma-rays of plant extracts with proven antioxidant activity, and to elucidate the antigenotoxic mechanisms involved in radioprotection using this system. MATERIALS AND METHODS: The methodology developed was assayed with amifostine, the most studied radioprotector, and with Phyllanthus orbicularis HBK, Cymbopogon citratus (DC) Stapf and Pinus caribaea Morelet extracts, using pre- and post-treatment procedures. RESULTS: The P. caribaea and C. citratus extracts were antigenotoxic against gamma-rays when the cells were pre-treated with both extracts, suggesting a possible antigenotoxic action through a free radical scavenging mechanisms. Amifostine and the P. orbicularis extract were also antigenotoxic under pre- and post-treatment conditions, indicating that several antimutagenic components of this plant extract may also operate by some intracellular mechanism, unlike its antioxidant activity. CONCLUSIONS: The results have demonstrated the usefulness of the modified SOS Chromotest assay in the screening of phytochemical radioprotectors as well as in the study of their antimutagenic mechanisms.
Subject(s)
Escherichia coli/drug effects , Escherichia coli/radiation effects , Mutagenicity Tests/methods , Plant Extracts/administration & dosage , Plants, Medicinal/chemistry , SOS Response, Genetics/drug effects , SOS Response, Genetics/radiation effects , DNA, Bacterial/genetics , DNA, Bacterial/radiation effects , Dose-Response Relationship, Drug , Dose-Response Relationship, Radiation , Drug Evaluation, Preclinical , Escherichia coli/genetics , Phytotherapy/methods , Radiation Dosage , Radiation-Protective Agents/administration & dosageABSTRACT
Punica granatum L (Punicaceae) es una planta medicinal cuyo fruto posee propiedades terapéuticas. El extracto obtenido a partir de frutos enteros se encuentra en fase de estudios preclínicos con el propósito de ser utilizado para el tratamiento de enfermedades virales. En los últimos años, algunas investigaciones experimentales han sido dirigidas al estudio de las propiedades antigenotóxicas de este extracto como una valiosa propiedad adicional. Algunos fitocomponentes del fruto de la granada muestran una actividad antioxidante potente y existen resultados experimentales que demuestran su capacidad como agentes antimutagénicos naturales. El presente trabajo expone los resultados obtenidos al valorar, en este extracto de granada, su capacidad de disminuir el daño inducido por el peróxido de hidrógeno en células de ovario de Hamster chino cultivadas in vitro. Se realizaron experimentos de carácter citogenético como es el intercambio de cromátidas hermanas y citofluorimétrico: la fluorimetría de la diclofluoreceína oxidada. En las condiciones experimentales de esta investigación, el extracto de frutos enteros de granada fue capaz de secuestrar especies reactivas del oxígeno producidas por el peróxido de hidrógeno, mecanismo mediante el cual ejerce su acción protectora del ADN frente a las lesiones causadas por este agente(AU)
Subject(s)
Lythraceae , Phytotherapy/methods , Hydrogen Peroxide/adverse effects , Cricetulus , Plant Extracts/therapeutic use , Sister Chromatid ExchangeABSTRACT
Punica granatum L (Punicaceae) es una planta medicinal cuyo fruto posee propiedades terapéuticas. El extracto obtenido a partir de frutos enteros se encuentra en fase de estudios preclínicos con el propósito de ser utilizado para el tratamiento de enfermedades virales. En los últimos años, algunas investigaciones experimentales han sido dirigidas al estudio de las propiedades antigenotóxicas de este extracto como una valiosa propiedad adicional. Algunos fitocomponentes del fruto de la granada muestran una actividad antioxidante potente y existen resultados experimentales que demuestran su capacidad como agentes antimutagénicos naturales. El presente trabajo expone los resultados obtenidos al valorar, en este extracto de granada, su capacidad de disminuir el daño inducido por el peróxido de hidrógeno en células de ovario de Hamster chino cultivadas in vitro. Se realizaron experimentos de carácter citogenético como es el intercambio de cromátidas hermanas y citofluorimétrico: la fluorimetría de la diclofluoreceína oxidada. En las condiciones experimentales de esta investigación, el extracto de frutos enteros de granada fue capaz de secuestrar especies reactivas del oxígeno producidas por el peróxido de hidrógeno, mecanismo mediante el cual ejerce su acción protectora del ADN frente a las lesiones causadas por este agente(AU)
Subject(s)
Animals , Cricetinae , Lythraceae , Phytotherapy , Antitoxins , Antimutagenic Agents , Hydrogen PeroxideABSTRACT
Punica granatum L (Punicaceae) es una planta medicinal cuyo fruto posee propiedades terapéuticas. El extracto obtenido a partir de frutos enteros se encuentra en fase de estudios preclínicos con el propósito de ser utilizado para el tratamiento de enfermedades virales. En los últimos años, algunas investigaciones experimentales han sido dirigidas al estudio de las propiedades antigenotóxicas de este extracto como una valiosa propiedad adicional. Algunos fitocomponentes del fruto de la granada muestran una actividad antioxidante potente y existen resultados experimentales que demuestran su capacidad como agentes antimutagénicos naturales. El presente trabajo expone los resultados obtenidos al valorar, en este extracto de granada, su capacidad de disminuir el daño inducido por el peróxido de hidrógeno en células de ovario de Hamster chino cultivadas in vitro. Se realizaron experimentos de carácter citogenético como es el intercambio de cromátidas hermanas y citofluorimétrico: la fluorimetría de la diclofluoreceína oxidada. En las condiciones experimentales de esta investigación, el extracto de frutos enteros de granada fue capaz de secuestrar especies reactivas del oxígeno producidas por el peróxido de hidrógeno, mecanismo mediante el cual ejerce su acción protectora del ADN frente a las lesiones causadas por este agente
Punica granatum L. (Punicaceae) is a medicinal plant whose fruit has therapeutical properties. The whole fruit extract is under preclinical study, with the objective of being used for viral disease treatment. In the last few years, some experimental research has been aimed at studying the antigenotoxic characteristics of this extract as an additional valuable property. Some phytocomponents of Punica granatum L. fruit show powerful antioxidative activity and certain experimental results prove their capacity as natural antimutagenic agents. The present paper set forth the results achieved in evaluating the capacity of this extract to reduce hydrogen peroxide-induced damage in in vitro cultured ovarian cells from Chinese Hamster. Cytogenetic experiments such as the exchange of sister chromatids and the cytofluometric test, i.e, oxidized diclofluorescein fluorimetry were performed. Under the experimental conditions of this research work, the Punica granatum whole fruit extract could sequestrate reactive oxygen species caused by hydrogen peroxide, a mechanism that allows it to protect the DNA against the lesions provoked by this agent.
Subject(s)
Animals , Cricetinae , Antimutagenic Agents , Antitoxins , Hydrogen Peroxide , Phytotherapy , LythraceaeABSTRACT
Phyllanthus orbicularis HBK (Euphorbiaceae) is a medicinal plant, endemic to Cuba, whose aqueous extract has proven antimutagenic effects against hydrogen peroxide and some promutagenic aromatic amines (AAs), in addition to its antiviral properties. In this paper, antimutagenesis of this extract against two carcinogenic AAs, 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) and 4-aminobiphenyl (4-ABP) has been studied. Liver microsomal fractions from both induced rats and humans were used to metabolise both procarcinogenic compounds in the Salmonella assay. The plant extract was effective in reducing the mutagenesis of these AAs, activated by both kinds of fractions. The optimal antimutagenic effect was obtained when both AAs were metabolised by human enzymes, with an almost total reduction of 4-ABP mutagenesis and a decrease of about 75% of PhIP mutagenicity. Mutagenicity of both AAs, activated by induced rat fraction, was only decreased by about 50%. Inhibition by plant extract of alkoxyresorufin O-dealkylation activities, dependent on CYP1A, of both fractions was determined. In accordance with the results obtained, the inhibition or modulation of CYP1A subfamily activities, and possibly of CYP1A2, is thought to be the main mechanism of antimutagenesis of the aqueous extract of Phyllanthus orbicularis against 4-ABP and PhIP.
Subject(s)
Aminobiphenyl Compounds/metabolism , Cytochrome P-450 Enzyme System/metabolism , Imidazoles/metabolism , Phyllanthus , Animals , Dose-Response Relationship, Drug , Humans , Microsomes, Liver/drug effects , Microsomes, Liver/metabolism , Plant Extracts/isolation & purification , Plant Extracts/pharmacology , Plant Leaves , Plant Stems , RatsABSTRACT
Phyllanthus orbicularis HBK is an endemic Cuban plant whose aqueous extract has been proposed as an effective drug for the treatment of viral diseases. In addition, antimutagenic properties of this extract have also been reported. In the present study, the genotoxicity of this plant extract was assessed using different in vitro and in vivo assays. Results from SOS gene induction, gene reversion and conversion, and SMART assays clearly show that P. orbicularis aqueous extract does not induce either primary DNA damage or mutation. Additionally, no statistically significant difference was found in the percentage of chromosomal aberrations in Chinese hamster ovarian (CHO) cells treated with the plant extract. On the contrary, micronuclei and abnormal anaphase were induced by this extract in CHO cells. This genotoxic effect was related to a high cytotoxicity. Single spots were detected in the SMART assay. These results point to a possible aneugenic effect of the P. orbicularis aqueous extract at cytotoxic doses which are much higher than those seen by their antiviral and antimutagenic activities.
