Percorrer por autor "Pimenta, Andreia I."
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- Assessment of gamma radiation effects on antioxidant activity of cork wastewaterPublication . Madureira, Joana; Pimenta, Andreia I.; Dias, Maria Inês; Melo, Rita; Santos, Pedro M.P.; Falcão, António N.; Cabo Verde, Sandra; Ferreira, Isabel C.F.R.; Margaça, Fernanda M.A.Cork cooking wastewater results from the process of boiling cork planks. It is an aqueous and complex dark liquor with high concentration of phenolic compounds such as phenolic acids and tannins [1, 2], which are known for their high antioxidant activity. The aim of this work is to perform a compreensive assessment of the effects of gamma radiation on the antioxidant activity of cork cooking water. The irradiation experiments were carried out at room temperature in a Co-60 experimental equipment (Prescisa 22, Graviner, Lda, UK), with an activity of 140 Tbq (3.77 kCi) and at a dose rate of 1.5 kGy/h, located at the Centro de Ciências e Tecnologias Nucleares (Portugal). Samples of wastewater were irradiated at. three distinct. doses (10, 20 and 50 KGy) and the antioxidant activity was evaluated by in vitro assays based on different mechanisms of action: DPPH radical scavenging activity, reducing power and inhibition of β-carotene bleaching. Antioxidant capacity was compared with the physico-chemical characterization [3) of cork wastewater - Chemical Oxygen Demand (COD), Biochemical Oxygen Demand (BOD), Total Suspended Solids (TSS) and Total Phenolic Content. (TP) - when exposed to gamma radiation. The obtained results point out that gamma radiation induces changes in complex compounds leading to an increase in the antioxidant capacity. These results demonstrate the potential of this technology in order to increase the added value of cork wastewaters.
- Avaliação do perfil fenólico de duas plantas comummente utilizadas na medicina tradicional, após aplicação de irradiação ionizantePublication . Pereira, Eliana; Pimenta, Andreia I.; Mandim, Filipa; Calhelha, Ricardo C.; Antonio, Amilcar L.; Barros, Lillian; Santos-Buelga, Celestino; Cabo Verde, Sandra; Ferreira, Isabel C.F.R.Os compostos fenólicos têm sido associados a diferentes efeitos benéficos nomeadamente, na prevenção de doenças, nomeadamente diabetes, cancro, doenças cardiovasculares, obesidade, doenças neuro-degenerativas, entre outras. São várias as matrizes que representam uma boa fonte deste tipo de compostos, principalmente no reino vegetal [1,2]. Assim, este estudo pretendeu avaliar os efeitos da radiação gama na composição fenólica de extratos aquosos, obtidos por infusão de duas plantas comummente apreciadas pelo consumidor e usadas na medicina tradicional - Aloysia citrodora L. e Mentha x piperita L.. O tratamento de irradiação foi realizado através de uma câmara de 60Co, aplicando as doses de 1 e 10 kGy e os resultados foram comparados com amostras controlo (0 kGy). O perfil fenólico foi obtido por HPLC-DAD-ESI/MS. Foram identificados 11 e 14 compostos fenólicos (derivados de flavonoides e ácidos fenólicos) nas espécies A. citrodora e M. piperita, respetivamente. Relativamente aos resultados obtidos após a aplicação deste tipo de processamento, foi evidente que as amostras submetidas a uma dose de irradiação de 10 kGy, revelaram diferenças estatisticamente significativas no perfil fenólico de ambos os extratos estudados, comparativamente com a amostra controlo (0 kGy), evidenciando um aumento na maioria dos compostos, como também nos teores de ácidos fenólicos totais e compostos fenólicos totais [3]. Assim, este estudo contribuiu para um conhecimento mais amplo dos efeitos da irradiação gama na caraterização destas moléculas em algumas plantas medicinais, revelando também que este tipo de processamento é uma técnica recomendada para aplicação nesta matriz.
- Avaliação do perfil fenólico de duas plantas comummente utilizadas na medicina tradicional, após aplicação de irradiação ionizantePublication . Pereira, Eliana; Pimenta, Andreia I.; Mandim, Filipa; Calhelha, Ricardo C.; Antonio, Amilcar L.; Barros, Lillian; Santos-Buelga, Celestino; Cabo Verde, Sandra; Ferreira, Isabel C.F.R.Os compostos fenólicos têm sido associados a diversos efeitos benéficos nomeadamente, na prevenção de algumas doenças, tais como, diabetes, cancro, doenças cardiovasculares, obesidade, doenças neuro-degenerativas, entre outras. São várias as matrizes que representam uma boa fonte deste tipo de compostos, principalmente no reino vegetal. Assim, este estudo pretendeu avaliar os efeitos da radiação gama na composição fenólica de extratos aquosos, obtidos por infusão de duas plantas comummente apreciadas pelo consumidor e usadas na medicina tradicional - Aloysia citrodora L. (limonete) e Mentha x piperita L. (hortelã-pimenta). O tratamento de irradiação foi realizado através de uma câmara de 60Co, aplicando as doses de 1 e 10 kGy e os resultados foram comparados com amostras controlo (0 kGy). O perfil fenólico foi obtido por HPLC-DAD-ESI/MS. Foram identificados 11 e 14 compostos fenólicos (derivados de flavonoides e ácidos fenólicos) nas espécies A. citrodora e M. piperita, respetivamente. Relativamente aos resultados obtidos após a aplicação deste tipo de processamento, foi evidente que as amostras submetidas a uma dose de irradiação de 10 kGy, revelaram diferenças estatisticamente significativas no perfil fenólico de ambos os extratos estudados, comparativamente com a amostra controlo (0 kGy), evidenciando um aumento na maioria dos compostos, como também nos teores de ácidos fenólicos totais e compostos fenólicos totais. Assim, este estudo contribuiu para um conhecimento mais amplo dos efeitos da irradiação gama nestas moléculas, revelando também que este tipo de processamento pode ser aplicado em plantas aromáticas e medicinais.
- Effects of gamma irradiation on cytotoxicity and phenolic compounds of Thymus vulgaris L. and Mentha x piperita L.Publication . Pereira, Eliana; Pimenta, Andreia I.; Calhelha, Ricardo C.; Antonio, Amilcar L.; Cabo Verde, Sandra; Barros, Lillian; Santos-Buelga, Celestino; Ferreira, Isabel C.F.R.The aim of the present study was to evaluate the effects of gamma irradiation on cytotoxicity and phenolic compounds of Thymus vulgaris L. and Menta × piperita L. (methanolic extracts), used in traditional medicine. Thirteen and fourteen phenolic compounds, including caffeoyl derivatives and flavonoid glycosides, were detected in T. vulgaris and Mentha piperita, respectively, none of which was affected by the irradiation dose used (10 kGy). Furthermore, the irradiation up to 10 kGy did not change the cytotoxic properties of peppermint samples on tumor cell lines (MCF-7, NCI-H460, HeLa and HepG2), whereas thyme samples irradiated at 10 kGy increased their cytotoxicity in the assayed tumor cell lines compared with samples submitted to 2 and 5 kGy. All in all, the dose of 10 kGy was considered as suitable to be applied for the purpose of disinfestation and microbial decontamination of these plants without modifying their phenolic composition and bioactive properties.
- Effects of gamma radiation on cork wastewater: Antioxidant activity and toxicityPublication . Madureira, Joana; Pimenta, Andreia I.; Popescu, Larisa; Besleaga, Alexandra; Dias, Maria Inês; Santos, Pedro M.P.; Melo, Rita; Ferreira, Isabel C.F.R.; Cabo Verde, Sandra; Margaça, Fernanda M.A.A comprehensive assessment of the toxicity and antioxidant activity of cork boiling wastewater and the effects of gamma radiation on these parameters was performed. Antioxidant activity was evaluated using different methodologies as DPPH radical scavenging activity, reducing power and inhibition of ß-carotene bleaching. The results have shown that gamma radiation can induce an increase on the antioxidant activity of cork boiling wastewater. Toxicity tests were performed to access the potential added value of the irradiated wastewaters and/or minimization of the impact for discharge in the environment. Two different methods for toxicity evaluation were followed, bacterial growth inhibition test and cytotoxicity assay, in order to predict the behavior of different cells (prokaryotic and eukaryotic) in the presence of cork wastewater. Non-treated cork boiling wastewater seemed to be non-toxic for prokaryotic cells (Pseudomonas fluorescens and Bacillus subtilis) but toxic for eukaryotic cells (A549 human cells and RAW264.7 mouse cells). The gamma radiation treatment at doses of 100 kGy appeared to increase the toxicity of cork compounds for all tested cells, which could be related to a toxic effect of radiolytic products of cork compounds in the wastewaters.
- Effects of gamma radiation on phenolic composition of medicinal plants: Aloysia Citrodora L. and Mentha X Piperita L. InfusionsPublication . Pereira, Eliana; Pimenta, Andreia I.; Antonio, Amilcar L.; Calhelha, Ricardo C.; Barros, Lillian; Santos-Buelga, Celestino; Cabo Verde, Sandra; Ferreira, Isabel C.F.R.Irradiation is a food processing technique supported by several globally recognized organizations (FAO, WHO, IAEA), being suitable for several food matrices, prolonging not only the shelf life of the food, but also providing microbiological decontamination. This work aimed to evaluate the effects of gamma radiation on the phenolic composition of Aloysia citrodora L. and Mentha x piperita L. infusions. Gamma radiation treatment was performed in a 60Co chamber, applying doses between 1 and 10 kGy and the results were compared with the control sample (non-irradiated, 0 kGy). The phenolic profile was determined and identified by HPLC-DAD-ESI/MS. Radiation treatment (at a dose of 10 kGy) caused statistically significant effects on the phenolic profile in both infusions, evidencing an increase in most of detected compounds, namely the majority ones. The same irradiation dose also induced an increase on the content of total phenolic acids and total phenolic compounds [1]. The results of this study can contribute to a wider knowledge of the effects of gamma irradiation on relevant bioactive compounds of several aromatic and medicinal plants, being recommended its application in these matrices.
- Effects of gamma radiation on phenolic composition, cytotoxicity, antibacterial and virucidal activities of two medicinal plantsPublication . Pereira, Eliana; Pimenta, Andreia I.; Calhelha, Ricardo C.; Antonio, Amilcar L.; Barros, Lillian; Santos-Buelga, Celestino; Cabo Verde, Sandra; Ferreira, Isabel C.F.R.The consumers' interest for a healthier diet and the use of natural products in the prevention and/or treatment of health problems has triggered an intensive search for bioactive plant compounds. Plants are a good source of phenolic compounds, terpenoids, alkaloids, quinones, carotenoids, sterols, glucosinolates and other compounds, which provide health benefits due to their wide range of biological properties. This work aimed to evaluate the effects of gamma radiation on the phenolic composition, cytotoxicity, virucidal and antimicrobial properties of Aloysia citrodora L. and Mentha x piperita L. infusions. Gamma radiation treatment was performed in a 60Co chamber, applying the doses of 1 and 10 kGy and the results were compared with the control sample (0 kGy). The phenolic compounds profile was obtained by HPLC-DAD-ESI/MS and the cytotoxicity was evaluated in human tumour cell lines and in a primary cell culture. For virucidal efficacy evaluation, MNV-1 and HAdV-5 viral titers were determined by plaque assay in Raw264.7 and A549 cell lines, respectively. The antibacterial activity was evaluated against Gram-negative and Gram-positive bacteria. Radiation treatment has been shown to cause different effects on phenolic concentrations and virucidal efficacy, depending on the plant species studied, the virus and the absorbed dose. In cytotoxicity assay A. citrodora did not reveal significant statistically differences considering the different doses applied, however M. piperita at 10 kGy stood out with the highest cytotoxic potential in all tested cell lines. Regarding antibacterial assays, S. aureus was the only bacteria that was sensible to the infusions of non-irradiated and 1 kGy irradiated in both species. Thus, this study contribute to a wider knowledge of the effects of gamma irradiation on several relevant bioactive potentials of some aromatic and medicinal plants and showed that gamma radiation is a technique recommended for these matrices.
- Effects of gamma radiation on the bioactivity of medicinal and aromatic plants: Mentha × piperita L., Thymus vulgaris L. and Aloysia citrodora Paláu as case studiesPublication . Pereira, Eliana; Pimenta, Andreia I.; Barros, Lillian; Calhelha, Ricardo C.; Antonio, Amilcar L.; Cabo Verde, Sandra; Ferreira, Isabel C.F.R.Irradiation is a feasible and safe decontamination technique, being applied to several types of foods including edible and medicinal plants. The aim of this study was to evaluate the effects of different gamma radiation doses (1, 5 and 10 kGy) on the individual profile of phenolic compounds determined by HPLC-DAD-ESI/MS, and the bioactive potential (cytotoxic, virucidal, and antimicrobial activities) of Aloysia citrodora Paláu (lemon verbena), Mentha × piperita L. (peppermint) and Thymus vulgaris L. (thyme). The observed cytotoxic activity varied with the plant and with the applied dose, being higher in Thymus vulgaris irradiated with 10 kGy. The virucidal activity was also dependent on the radiation dose, but was preserved with irradiation treatment. Gamma rays had no effect on the antimicrobial activity of the studied plants. Otherwise, the effects of gamma radiation on the phenolic profile were heterogeneous, with an increase in some compounds and decrease in others, depending on the species and on the radiation dose.
- How gamma radiation affects antimicrobial potential of medicinal plants: Mentha x piperita L. as a case studyPublication . Pereira, Eliana; Pimenta, Andreia I.; Barros, Lillian; Antonio, Amilcar L.; Cabo Verde, Sandra; Ferreira, Isabel C.F.R.Medicinal plants are being used by the food and pharmaceutic industries to extract relevant compounds. To be used in these industries as raw materials, it is required the non-presence of microorganisms. Therefore, it is essential that they undergo a decontamination process before entering processing lines, and these methods should not compromise their bioactive properties. In this context a non-thermal technology, gamma irradiation, was used as a decontamination procedure. For this purpose, samples of Mentha piperita L. (peppermint) was irradiated using a 60Co experimental chamber, at the doses of 1, 5, and 10 kGy. The hydroethanolic extracts were then further evaluated through the virucidal efficacy assay, using two enteric viruses – human adenovirus type-5 (HAdV-5) and murine norovirus type-1 (MNV-1, as a human norovirus surrogate). The antibacterial activity was evaluated against a set of Gram-positive and Gram-negative bacteria. For the virucidal activity, data suggested that the irradiation treatment of all species can preserve the natural properties of the plant against enteric viral pathogens. The hydroethanolic extracts of peppermint reveal a low antibacterial potential for all the tested bacteria. However, antibacterial activity of gamma irradiated samples did not affect this bioactivity for none of the microbial agents tested. Validation of antimicrobial potential of medicinal plants, after gamma irradiation processing, are scarce in the literature. This study allowed defining the influence of this treatment on the bioactive properties of peppermint.
- Infusions of gamma irradiated Aloysia citrodora L. and Mentha x piperita L.: Effects on phenolic composition, cytotoxicity, antibacterial and virucidal activitiesPublication . Pereira, Eliana; Pimenta, Andreia I.; Calhelha, Ricardo C.; Antonio, Amilcar L.; Barros, Lillian; Santos-Buelga, Celestino; Cabo Verde, Sandra; Ferreira, Isabel C.F.R.The incorporation of plants in industry requires high standards of hygiene, being the raw materials obligatorily decontaminated. Irradiation is increasingly applied as a decontamination technique in several countries. This work aimed to evaluate the effects of gamma radiation on the phenolic composition, cytotoxicity, virucidal and antimicrobial properties of Aloysia citrodora L. (lemon verbena) and Mentha x piperita L. (peppermint) infusions. Phenolic compounds profile was obtained by HPLC-DAD-ESI/MS and cytotoxicity was ev aluated in human tumour and non-tumour cell lines; in virucidal efficacy, MNV-1 and HAdV-5 viral titers were determined by plaque assay in Raw264.7 and A549 cell lines, respectively; and the antibacterial potential was evaluated against Gram-negative and Gram-positive bacteria. Radiation treatment caused a significant increase in total phenolic compounds of both plants, while the virucidal efficacy was depend on the plant, the virus, and absorbed dose. S. aureus, with MIC and MBC values of 5 mg/mL, was the only bacteria sensible to the infusions of non-irradiated and 1 kGy irradiated lemon verbena and peppermint samples; gamma radiation appears to cause no alteration in the antibacterial potential of the studied plants. Peppermint infusion (irradiated at 10 kGy) showed the highest cytotoxic potential in all tumour cell lines.