Avaliação de extratos e substâncias de Pterogyne nitens Tul. (Fabaceae) contra nematoides de interesse veterinário
Carregando...
Arquivos
Data
2020-04-03
Autores
Lima, Caroline Sprengel
Título da Revista
ISSN da Revista
Título de Volume
Editor
Universidade Estadual Paulista (Unesp)
Resumo
Um dos maiores problemas sanitários encontrados pela pecuária são os nematoides gastrintestinais (NGIs), os quais causam perdas significativas aos pecuaristas de pequenos ruminantes. O controle de NGIs é realizado com base na administração repetida e imprópria dos anti-helmínticos (AHs) convencionais, havendo uma crescente presença de resíduos no meio ambiente ou em produtos de consumo. Acima de tudo, o desenvolvimento de resistência em populações de NGIs tornou-se um problema mundial. A fim de preservar a saúde dos hospedeiros, bem como retardar a resistência, torna-se necessário identificar métodos alternativos ao uso de AHs, tais como o uso de plantas, seus extratos e substâncias. Pterogyne nitens Tul. (Fabaceae), árvore nativa brasileira, apresenta indicações de uso popular como vermífugo, bem como de diversas substâncias bioativas, tais como: ácidos fenólicos, flavonoides, alcaloides guanidínicos, terpenos e esteróis. O presente estudo teve como objetivo investigar os efeitos de extratos e substâncias de P. nitens em diferentes estágios do ciclo de vida de três isolados susceptíveis originários do Brasil e da França de duas espécies de NGIs, Haemonchus contortus e Trichostrongylus colubriformis. Foram preparados três extratos etanólicos a partir das folhas (EEL), frutos (EEFR) e flores (EEFL); e oito substâncias fenólicas isoladas [duas flavonas (sorbifolina e pedalitina), dois flavonóis (quercetina e rutina), um flavan-3-ol (ourateacatequina) e três ácidos fenólicos (ácido caféico, ácido ferúlico e ácido gálico)]. E, adicionalmente, dois flavonoides (crisina e morina) foram obtidos comercialmente da Merck®, para auxiliar os estudos de relação entre estrutura química e atividade anti-helmíntica. Os extratos e substâncias foram avaliados contra eclosão de ovos, desenvolvimento larval (L1 para L3) e desembainhamento larval (L3). O EEFL não foi testado nos ensaios, pois sua massa obtida foi suficiente apenas para o isolamento das substâncias. Além de ser uma parte da planta de difícil acesso, em que se dá apenas uma vez e em poucos meses do ano. Ambos extratos etanólicos demonstraram potente atividade anti-helmíntica in vitro contra as duas espécies de NGIs nos três ensaios analisados. No ensaio de eclosão de ovos, o extrato etanólico de folhas (EEL, de 2,9 mg/mL e 316 µg/mL) apresentou atividade anti-helmíntica duas vezes mais potente do que o extrato etanólico de frutos (EEFR, 5,9 mg/mL e 512 µg/mL) contra T. colubriformis e H. contortus, respectivamente. No ensaio de desenvolvimento larval, EEL e EEFR apresentaram valores de EC50 de 8,9 e 20 µg/mL contra T. colubriformis, e EC50 de 47 e 35 µg/mL contra o isolado brasileiro de H. contortus, respectivamente. No caso do ensaio de desembainhamento larval, os valores de EC50 de ambos extratos variaram de 78,6‒158 µg/mL para os três isolados de ambas espécies de NGIs. Esses resultados nos encorajaram a investigar as substâncias que poderiam ser responsáveis pela atividade anti-helmíntica dos extratos etanólicos. Ácidos fenólicos e flavonas foram os mais ativos contra a eclosão de ovos (0,56–4,93 µg/mL) e desenvolvimento larval (18 e 83 µg/mL) do isolado brasileiro de H. contortus, respectivamente. Quercetina foi a substância mais ativa contra eclosão de ovos (0,4 µg/mL) e o desenvolvimento larval (100 µg/mL) de T. colubriformis. Além disso, apresentou eficácia de 1,62 e 5,83 µg/mL contra o desembainhamento larval dos isolados francês e brasileiro de H. contortus, respectivamente. Vale ressaltar que este é o primeiro estudo avaliando a atividade antihelmíntica de P. nitens, bem como algumas substâncias contra H. contortus e T. colubriformis. Contudo, análises in vivo, incluindo estudos de eficácia e segurança, são necessários para melhor entendimento da atividade anti-helmíntica dessas substâncias.
One of the considerable health problems encountered by livestock is gastrointestinal nematodes (GINs), as they cause significant losses to small ruminant breeders. The control of GINs is based on the repeated and improper administration of synthetic anthelmintics (AHs), causing an increase of environmental residues and in food. Furthermore, the development of resistance in GIN populations has become a worldwide problem. In order to preserve the health of the hosts, as well as reduce resistance, it became necessary to identify AH alternative methods, such as the use of medicinal plants and their extracts and compounds. Pterogyne nitens Tul. (Fabaceae), brazilian native tree, presents popular use as a vermifuge and several bioactive compounds, such as phenolic acids, flavonoids, guanidine alkaloids, terpenes, and sterols. The aim of the current study was to investigate the effects of extracts and compounds from P. nitens against the different stages of the life cycle of three susceptible isolates from Brazil and France of two GIN species, Haemonchus contortus, and Trichostrongylus colubriformis. Three ethanolic extracts were prepared from leaves (EEL), fruits (EEFR), and flowers (EEFL). Eight phenolic compounds were isolated [two flavones (sorbifolin and pedalitin), two flavonols (quercetin and rutin), one flavan-3-ol (ouratecatechin) and three phenolic acids (caffeic acid, ferulic acid, and gallic acid)]. In addition, two flavonoids (chrysin and morin) were obtained commercially from Merck®, to derive the chemical structure and AH activity relationship studies. Extracts and compounds were evaluated against hatching eggs, larval development, and larval exsheathment (L3). EEFL was not tested, because as the extracted mass obtained was sufficient only for the isolation of the compounds. As well as it is an element of the plant that is difficult to access once the flowering occurs in a few months of the year. Ethanolic extracts demonstrated a potent in vitro AH activity against both GINs in the three assays. In the egg hatch assay, the ethanolic extract of leaves (EEL, 2.9 mg/mL and 316 µg/mL) showed AH activity twice as potent as the ethanol extract of fruits (EEFR, 5.9 mg/mL and 512 µg/mL) against T. colubriformis and H. contortus, respectively. In the larval development assay, EEL and EEFR showed EC50 values of 8.9 and 20 µg/mL against T. colubriformis, and EC50 of 47 and 35 µg/mL against the brazilian isolate of H. contortus, respectively. In the case of the larval exsheathment assay, both extracts EC50 values varied from 78.6‒158 µg/mL for the three isolates of both NGI species. These results encouraged us to investigate the compounds that could be responsible for the AH activity of ethanol extracts. Phenolic acids and flavones were the most active against hatching eggs (0.56–4.93 µg/mL) and larval development (18 and 83 µg/mL) of the H. contortus brazilian isolate, respectively. Quercetin was the most active substance against hatching eggs (0.4 µg/mL) and larval development (100 µg/mL) of T. colubriformis. In addition, it showed the efficacy of 1.62 and 5.83 µg/mL against the larval exsheathment of H. contortus French and Brazilian isolates, respectively. It is worth mentioning that this is the first anthelmintic evaluation of P. nitens, as well as some substances against H. contortus e T. colubriformis. However, in vivo analyzes, including studies of efficacy and safety, are necessary to better understand the AH activity of these compounds.
One of the considerable health problems encountered by livestock is gastrointestinal nematodes (GINs), as they cause significant losses to small ruminant breeders. The control of GINs is based on the repeated and improper administration of synthetic anthelmintics (AHs), causing an increase of environmental residues and in food. Furthermore, the development of resistance in GIN populations has become a worldwide problem. In order to preserve the health of the hosts, as well as reduce resistance, it became necessary to identify AH alternative methods, such as the use of medicinal plants and their extracts and compounds. Pterogyne nitens Tul. (Fabaceae), brazilian native tree, presents popular use as a vermifuge and several bioactive compounds, such as phenolic acids, flavonoids, guanidine alkaloids, terpenes, and sterols. The aim of the current study was to investigate the effects of extracts and compounds from P. nitens against the different stages of the life cycle of three susceptible isolates from Brazil and France of two GIN species, Haemonchus contortus, and Trichostrongylus colubriformis. Three ethanolic extracts were prepared from leaves (EEL), fruits (EEFR), and flowers (EEFL). Eight phenolic compounds were isolated [two flavones (sorbifolin and pedalitin), two flavonols (quercetin and rutin), one flavan-3-ol (ouratecatechin) and three phenolic acids (caffeic acid, ferulic acid, and gallic acid)]. In addition, two flavonoids (chrysin and morin) were obtained commercially from Merck®, to derive the chemical structure and AH activity relationship studies. Extracts and compounds were evaluated against hatching eggs, larval development, and larval exsheathment (L3). EEFL was not tested, because as the extracted mass obtained was sufficient only for the isolation of the compounds. As well as it is an element of the plant that is difficult to access once the flowering occurs in a few months of the year. Ethanolic extracts demonstrated a potent in vitro AH activity against both GINs in the three assays. In the egg hatch assay, the ethanolic extract of leaves (EEL, 2.9 mg/mL and 316 µg/mL) showed AH activity twice as potent as the ethanol extract of fruits (EEFR, 5.9 mg/mL and 512 µg/mL) against T. colubriformis and H. contortus, respectively. In the larval development assay, EEL and EEFR showed EC50 values of 8.9 and 20 µg/mL against T. colubriformis, and EC50 of 47 and 35 µg/mL against the brazilian isolate of H. contortus, respectively. In the case of the larval exsheathment assay, both extracts EC50 values varied from 78.6‒158 µg/mL for the three isolates of both NGI species. These results encouraged us to investigate the compounds that could be responsible for the AH activity of ethanol extracts. Phenolic acids and flavones were the most active against hatching eggs (0.56–4.93 µg/mL) and larval development (18 and 83 µg/mL) of the H. contortus brazilian isolate, respectively. Quercetin was the most active substance against hatching eggs (0.4 µg/mL) and larval development (100 µg/mL) of T. colubriformis. In addition, it showed the efficacy of 1.62 and 5.83 µg/mL against the larval exsheathment of H. contortus French and Brazilian isolates, respectively. It is worth mentioning that this is the first anthelmintic evaluation of P. nitens, as well as some substances against H. contortus e T. colubriformis. However, in vivo analyzes, including studies of efficacy and safety, are necessary to better understand the AH activity of these compounds.
Descrição
Palavras-chave
Anti-helmíntico, Pterogyne nitens, Compostos fenólicos, Haemonchus contortus, Trichostrongylus colubriformis, Anthelmintic, Phenolic compounds