RESUMO
Low-molecular-weight organic acid (OA) extrusion by plant roots is critical for plant nutrition, tolerance to cations toxicity, and plant-microbe interactions. Therefore, methodologies for the rapid and precise quantification of OAs are necessary to be incorporated in the analysis of roots and their exudates. The spatial location of root exudates is also important to understand the molecular mechanisms directing OA production and release into the rhizosphere. Here, we report the development of two complementary methodologies for OA determination, which were employed to evaluate the effect of inorganic ortho-phosphate (Pi) deficiency and aluminum toxicity on OA excretion by Arabidopsis roots. OA exudation by roots is considered a core response to different types of abiotic stress and for the interaction of roots with soil microbes, and for decades has been a target trait to produce plant varieties with increased capacities of Pi uptake and Al tolerance. Using targeted ultra-performance liquid chromatography coupled with high-resolution tandem mass spectrometry (UPLC-HRMS/MS), we achieved the quantification of six OAs in root exudates at sub-micromolar detection limits with an analysis time of less than 5 min per sample. We also employed targeted (MS/MS) matrix-assisted laser desorption/ionization (MALDI) mass spectrometry imaging (MSI) to detect the spatial location of citric and malic acid with high specificity in roots and exudates. Using these methods, we studied OA exudation in response to Al toxicity and Pi deficiency in Arabidopsis seedlings overexpressing genes involved in OA excretion. Finally, we show the transferability of the MALDI-MSI method by analyzing OA excretion in Marchantia polymorpha gemmalings subjected to Pi deficiency.
Assuntos
Ácidos/química , Alumínio/toxicidade , Fósforo/administração & dosagem , Exsudatos de Plantas/química , Raízes de Plantas/química , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz/métodos , Arabidopsis/química , Arabidopsis/efeitos dos fármacos , Arabidopsis/metabolismo , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Marchantia/química , Marchantia/efeitos dos fármacos , Marchantia/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Plantas Geneticamente ModificadasRESUMO
The cytotoxicity of three extracts (petroleum ether, ethyl acetate and n-butanol) from a plant used in folk medicine, Marchantia convoluta, to human non-small cell lung carcinoma (H1299) and liver carcinoma (HepG2) cell lines was tested. After 72-h incubation of lung and liver cancer cell cultures with varying concentrations of extracts (15 to 200 microg/mL), cytotoxicity was determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and reported in terms of cell viability. The extracts that showed a significant cytotoxicity were subjected to gas chromatography-mass spectrometry analysis to identify the components. The ethyl acetate, but not the petroleum ether or n-butanol extract, had a significant cytotoxicity against lung and liver carcinoma cells with IC50 values of 100 and 30 microg/mL, respectively. A high concentration of ethyl acetate extract (100 microg/mL) rapidly reduced the number of H1299 cells. At lower concentrations of ethyl acetate extract (15, 30, and 40 microg/mL), the numbers of HepG2 cells started to decrease markedly. Gas chromatography-mass spectrometry analysis of the ethyl acetate extract revealed the presence of several compounds such as phytol (23.42%), 1,2,4-tripropylbenzene (13.09%), 9-cedranone (12.75%), ledene oxide (7.22%), caryophyllene (1.82%), and caryophyllene oxide (1.15%). HPLC analysis result showed that there were no flavonoids in ethyl acetate extract, but flavonoids are abundant in n-butanol extract. Further studies are needed regarding the identification, toxicity, and mechanism of action of active compounds.
Assuntos
Antineoplásicos Fitogênicos/uso terapêutico , Neoplasias Hepáticas/tratamento farmacológico , Neoplasias Pulmonares/tratamento farmacológico , Marchantia/química , Folhas de Planta/química , Antineoplásicos Fitogênicos/isolamento & purificação , Sobrevivência Celular/efeitos dos fármacos , Cromatografia Líquida de Alta Pressão , Ensaios de Seleção de Medicamentos Antitumorais , Cromatografia Gasosa-Espectrometria de Massas , Humanos , Concentração Inibidora 50 , Neoplasias Hepáticas/patologia , Neoplasias Pulmonares/patologia , Extratos Vegetais/uso terapêutico , Células Tumorais CultivadasRESUMO
The cytotoxicity of three extracts (petroleum ether, ethyl acetate and n-butanol) from a plant used in folk medicine, Marchantia convoluta, to human non-small cell lung carcinoma (H1299) and liver carcinoma (HepG2) cell lines was tested. After 72-h incubation of lung and liver cancer cell cultures with varying concentrations of extracts (15 to 200 æg/mL), cytotoxicity was determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and reported in terms of cell viability. The extracts that showed a significant cytotoxicity were subjected to gas chromatography-mass spectrometry analysis to identify the components. The ethyl acetate, but not the petroleum ether or n-butanol extract, had a significant cytotoxicity against lung and liver carcinoma cells with IC50 values of 100 and 30 æg/mL, respectively. A high concentration of ethyl acetate extract (100 æg/mL) rapidly reduced the number of H1299 cells. At lower concentrations of ethyl acetate extract (15, 30, and 40 æg/mL), the numbers of HepG2 cells started to decrease markedly. Gas chromatography-mass spectrometry analysis of the ethyl acetate extract revealed the presence of several compounds such as phytol (23.42 percent), 1,2,4-tripropylbenzene (13.09 percent), 9-cedranone (12.75 percent), ledene oxide (7.22 percent), caryophyllene (1.82 percent), and caryophyllene oxide (1.15 percent). HPLC analysis result showed that there were no flavonoids in ethyl acetate extract, but flavonoids are abundant in n-butanol extract. Further studies are needed regarding the identification, toxicity, and mechanism of action of active compounds.