Publicação
Evaluation of the antioxidant and neuroprotective effects of extracts and compounds from medicinal plants of the genus Baccharis spp
| Resumo: | The antioxidant potential of plants has been received a great deal of attention because increased oxidative stress has been identified as a major causative factor in the development and progression of neurodegenerative diseases. Baccharis spp. plants have been demonstrated antioxidant, and neuroprotective properties. The goals of this work were (i) to characterize the phytochemical profiles of ethanolic extracts from the aerial parts B. dracunculifolia (BD) and B. trimera (BT), (ii) to evaluate in vitro antioxidant activity of BD and BT extracts, (iii) to study the cytotoxicity in BV2 cells after extracts exposure and (iv) to evaluate their neuroprotective effects in the seme cells when treated with herbicide Paraquat (PQ), known as oxidant agent. Phytochemical profiles of extracts were obtained by HPLC-DAD and showed that both extracts were composed by flavonoids and phenolic acids derivatives, powerful antioxidant agents. Antioxidant activity was evaluated using several in vitro models: free radical scavenging (DPPH, NO, O2 -•), iron chelation (ferrozine method), reduction power (FRAP method), and lipid peroxidation (β-carotene bleaching); quercetin was used as a reference antioxidant standard. Both extracts showed antioxidant activity in all assays, except BT that did not display an efficient chelating iron activity. In general, BD exhibited better antioxidant activities than BT, except in scavenging NO. Remarkably, BD demonstrated higher activity (p<0.05) than quercetin scavenging O2 -•radical. Cytotoxicity was evaluated by MTS assay, which measures metabolic activity, after 3 and 24 h of extract’s exposure. With the exception of 500 μg dwr/ml BD extract (24h) that induced significant toxicity comparing with control group (p≤0.01), none of the extracts induced cytotoxicity in the tested conditions. Neuroprotection was evaluated by resazurina assay, using co-incubation of extracts with 1 and 5 mM PQ. Co-incubation with 1mM PQ demonstrated that 500 μg dwr/ml BD extract (3 h recovery), 25 μg dwr/ml BD extract (24 h recovery), 100 μg dwr/ml BT extract (3 and 24 h recovery) and 25 μg dwr/ml BT extract (24 h recovery), significantly protect the cells from de damage caused by PQ, when compared with control group treated with insult alone. In coincubation with 5mM PQ BD extract did not confer protection and BT extract induced a decrease in cellular viability, when compared with cells subjected to PQ only, suggesting a prooxidant effect of the extract. |
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| Autores principais: | Marques, Bianca Patrícia Soares |
| Assunto: | Ciências Naturais::Outras Ciências Naturais |
| Ano: | 2017 |
| País: | Portugal |
| Tipo de documento: | dissertação de mestrado |
| Tipo de acesso: | acesso restrito |
| Instituição associada: | Universidade do Minho |
| Idioma: | inglês |
| Origem: | RepositóriUM - Universidade do Minho |
| Resumo: | The antioxidant potential of plants has been received a great deal of attention because increased oxidative stress has been identified as a major causative factor in the development and progression of neurodegenerative diseases. Baccharis spp. plants have been demonstrated antioxidant, and neuroprotective properties. The goals of this work were (i) to characterize the phytochemical profiles of ethanolic extracts from the aerial parts B. dracunculifolia (BD) and B. trimera (BT), (ii) to evaluate in vitro antioxidant activity of BD and BT extracts, (iii) to study the cytotoxicity in BV2 cells after extracts exposure and (iv) to evaluate their neuroprotective effects in the seme cells when treated with herbicide Paraquat (PQ), known as oxidant agent. Phytochemical profiles of extracts were obtained by HPLC-DAD and showed that both extracts were composed by flavonoids and phenolic acids derivatives, powerful antioxidant agents. Antioxidant activity was evaluated using several in vitro models: free radical scavenging (DPPH, NO, O2 -•), iron chelation (ferrozine method), reduction power (FRAP method), and lipid peroxidation (β-carotene bleaching); quercetin was used as a reference antioxidant standard. Both extracts showed antioxidant activity in all assays, except BT that did not display an efficient chelating iron activity. In general, BD exhibited better antioxidant activities than BT, except in scavenging NO. Remarkably, BD demonstrated higher activity (p<0.05) than quercetin scavenging O2 -•radical. Cytotoxicity was evaluated by MTS assay, which measures metabolic activity, after 3 and 24 h of extract’s exposure. With the exception of 500 μg dwr/ml BD extract (24h) that induced significant toxicity comparing with control group (p≤0.01), none of the extracts induced cytotoxicity in the tested conditions. Neuroprotection was evaluated by resazurina assay, using co-incubation of extracts with 1 and 5 mM PQ. Co-incubation with 1mM PQ demonstrated that 500 μg dwr/ml BD extract (3 h recovery), 25 μg dwr/ml BD extract (24 h recovery), 100 μg dwr/ml BT extract (3 and 24 h recovery) and 25 μg dwr/ml BT extract (24 h recovery), significantly protect the cells from de damage caused by PQ, when compared with control group treated with insult alone. In coincubation with 5mM PQ BD extract did not confer protection and BT extract induced a decrease in cellular viability, when compared with cells subjected to PQ only, suggesting a prooxidant effect of the extract. |
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