Loading...
Publication
Fight against parasites in veterinary medicine with active principles of plants
| Name: | Description: | Size: | Format: | |
|---|---|---|---|---|
| 5.59 MB | Adobe PDF |
Authors
Abstract(s)
A domesticação dos animais não faz só parte da história; está presente e continua nos dias de hoje. Atualmente, os animais de companhia têm uma importância muito expressiva na vida humana. Aproximadamente 70 milhões de famílias europeias têm pelo menos um destes animais. Adicionalmente, estamos perante um aumento da produção de gado com o intuito de satisfazer as necessidades alimentares da crescente população mundial. Um dos aspetos negativos que surgiu, e se tem mantido com estas interações humanos/animais é o aumento das infestações de parasitas e, consequentemente, o aumento do parasitismo nos seres humanos e animais.
Nos últimos anos, os gastos com cuidados de higiene animal aumentaram significativamente em todo o mundo. Por exemplo, de acordo com dados do European Scientific Counsel Companion Animal Parasites (ESCCAP), os desparasitantes representam 46% do mercado da saúde animal, cujo maior segmento é o dos ectoparasiticidas.
Os parasiticidas são usados desde a década de 20, sendo que os ectoparasiticidas são responsáveis pelo controlo dos ectoparasitas nos animais de companhia e produção. O uso de ectoparasiticidas permite reduzir o desconforto no animal, bem como a possibilidade de transmissão de doenças. Os ectoparasitas podem ser vetores de agentes patogénicos responsáveis pela transmissão de vírus, bactérias, helmintes e protozoários. Em alguns casos, pode ocorrer a transmissão de microrganismos entre os animais e seres humanos, zoonose, sendo esta mais uma evidência da necessidade de controlar eficazmente os ectoparasitas, pois podem representar um problema para a saúde pública.
Atualmente estamos perante um progressivo aumento da resistência aos compostos sintéticos, sendo isto uma ameaça difícil de resolver, uma vez que a maioria dos ectoparasiticidas usados são de origem sintética. Estes tipos de ectoparasiticidas têm suscitado preocupações crescentes em termos de impacto ambiental, saúde humana e resistência dos ectoparasitas aos compostos químicos utilizados como substâncias ativas. Tendo em conta a exigência do mercado e a pressão da legislação internacional para minimizar esses constrangimentos, é importante e essencial indagar abordagens alternativas mais seguras. Estas necessitam de demonstrar efetividade e viabilidade económica em simultâneo com um menor impacto ambiental.
A importância do tratamento adequado e o controlo de parasitas externos é, portanto, um alvo veterinário reconhecido e com repercussões a nível médico, tanto para a saúde animal como humana. Para alcançar esses objetivos, é necessário conhecer bem o alvo, nestes casos o ectoparasita, inclusive o seu ciclo de vida bem como a fisiologia do animal em que será aplicado o parasiticida.
As plantas têm sido utilizadas ao longo da história, inicialmente como fonte de alimento; contudo, com o avanço dos anos e dos conhecimentos adquiridos, começaram a ser utilizadas a nível medicinal e profilático.
Nos últimos 20 anos, o interesse na utilização de compostos naturais (extratos de plantas e óleos essenciais) tem vindo a aumentar, para o controlo de vários ectoparasitas tanto em humanos como em animais. De forma a encontrar opções exequíveis, e tendo em conta que existem inúmeras plantas com propriedades e princípios ativos diferenciados, é fundamental investigar e recolher dados científicos publicados, com o intuito de desenvolver ectoparasiticidas alternativos.
Muitas plantas possuem mecanismos naturais de defesa eficazes contra os seus agressores, como é o caso dos espinhos ou dos metabolitos secundários. A partir destes metabolitos é possível desenvolver produtos eficazes e aplicáveis em animais, tanto de companhia como de produção. Os compostos bioativos, ou seja, metabolitos secundários que exercem efeitos essencialmente toxicológicos nos ectoparasitas, podem ser obtidos através de várias partes de plantas, tais como folhas, caule, flor e fruto recorrendo a métodos de extração adequados ao objetivo. Dito isto, e uma vez que existem numerosas plantas e, portanto, uma grande variedade de compostos bioativos, é essencial compreender o modo de ação de cada uma para se adequar ao ciclo de vida do ectoparasita a ser controlado. Para além disso, é essencial que se conheça de forma exaustiva a espécie e o quimiótipo da planta selecionada, a fim de garantir uma menor variabilidade nos perfis químicos, de modo que a ação do produto final seja previsível. Uma das principais categorias de compostos bioativos que contribuem para o controlo dos ectoparasitas são os terpenos e alguns alcaloides.
Atualmente, já existem alguns produtos derivados de plantas cujo modo de ação dos seus compostos bioativos são conhecidos. No entanto, é ainda necessário realizar alguns testes in vitro e in vivo, para avaliarem a eficácia e modo de ação da maioria dos compostos extraídos de diferentes espécies de plantas.
Uma opção sustentável é rever o conhecimento das civilizações milenares sobre as plantas, assim como, apreender as suas propriedades de forma a prevenir e combater os parasitas. O conhecimento de como utilizá-los eficientemente permaneceu em algumas populações. No entanto, existe uma forte tendência para a sua perda devido ao fácil acesso a outros medicamentos de medicina convencional. A etnobotânica estuda a forma como as pessoas utilizam os recursos vegetais, bem como a relação entre o homem e as plantas, sendo um excelente procedimento para a junção deste tipo de conhecimentos tradicionais. A recolha de dados é frequentemente realizada junto das pessoas, através de entrevistas ou observação, que são as formas mais recorrentes de registar o conhecimento da população. Esta abordagem foi realizada pela Professora Doutora Noémia Farinha e pela Professora Doutora Orlanda Póvoa, do Instituto Politécnico de Portalegre - Escola Superior Agrária de Elvas, entre Julho de 2011 e Abril de 2012, no Alentejo. O objetivo fundamental foi proceder ao levantamento da utilização de plantas no tratamento de animais e, secundariamente, em humanos, realizando entrevistas para a obtenção de informações sobre o uso tradicional de várias espécies vegetais de diferentes famílias.
Considerando o objetivo principal desta dissertação: produzir um produto com função ectoparasiticida à base de extratos de plantas, para administrar em cães e alguns animais de produção, recorrendo aos dados gentilmente fornecidos pelas docentes, Professora Doutora Noémia Farinha e pela Professora Doutora Orlanda Póvoa, que foram avaliados no decorrer desta dissertação. Assim, a informação contida nas entrevistas foi selecionada do seguinte modo: respostas que mencionavam ectoparasitas, bem como uso em Canidae e/ou alguns animais de produção. Além disso, as plantas mencionadas em mais de uma entrevista foram selecionadas, analisadas e investigadas na literatura científica quanto ao seu potencial parasiticida.
Após reconhecimento do potencial ectoparasiticida das diferentes plantas selecionadas, sugere-se que seja preparado um ectoparasiticida com extractos de Juglans regia, Daphne gnidium e Ruta graveolens. O produto proposto, com possível potencial ectoparasiticida, usa como solvente isopropanol e água, sendo deste modo um excipiente hidroalcoólico, que permite proceder à utilização dos diferentes extratos de plantas, predominantemente alcoólicos e hidroalcoólicos, com modo de aplicação spot-on/pour-on, usando uma embalagem de poliácido láctico.
Para colocar no mercado um ectoparasiticida, serão necessários vários estudos para formular o produto. Será também essencial realizar testes adicionais para responder aos vários pontos do relatório público europeu de avaliação (EPAR).
Assim, são apresentados vários testes, sendo fulcral realizá-los, para que se obtenha a informação necessária, e por consequência, entender se o produto proposto é viável, tanto a nível de eficácia como de segurança para o animal, quer para a pessoa que o aplica e, para o ambiente.
De referir a falta de dados de algumas espécies de plantas, especialmente aquelas que são endémicas de Portugal, havendo por isso constrangimentos na procura de informação científica. Acresce ainda, que a falta de dados toxicológicos impediu, em muitos casos, uma avaliação real do possível uso e riscos associados; tal como a falta de dados sobre o modo de ação não permitiu avaliar a eficácia.
Esta dissertação visa destacar os benefícios e possibilidades de utilização de produtos derivados de plantas como ectoparasiticidas. Em suma, é possível utilizar estes produtos de uma forma profilática auxiliando no controlo de infestações, com um menor impacto ambiental, com baixa toxicidade para os mamíferos e contornando os problemas relacionados com a resistência aos ectoparasiticidas sintéticos.
The domestication of animals has been part of history for several decades and is still very present today. Currently, companion animals have very significant importance in human life. Approximately 70 million European families have at least one of these animals. Additionally, we are facing an increase in livestock to meet the food needs of the growing world population. Unfortunately, one of the negative aspects that have arisen, and has continued to occur, from these human/animal interactions is the increase in parasite infestations and, consequently, the rise in parasitism in humans and animals. In recent years, spending on animal healthcare has increased significantly worldwide. According to data from the European Scientific Counsel Companion Animal Parasites (ESCCAP), parasiticide account for 46% of the animal health market, whose largest segment is ectoparasiticides. Parasiticides have been used in parasite control since the 1920s, with ectoparasiticides being responsible for managing ectoparasites in companion animals and livestock. The use of ectoparasiticides reduces discomfort as well as the possibility of disease transmission. Parasites can be vectors of pathogens and responsible for the transmission of viruses, bacteria, helminths, and protozoa. In some cases, the transmission of microorganisms between animals and humans may occur, called zoonosis, which further highlights the need to effectively control ectoparasites, as they may represent a problem to public health. Moreover, we are currently facing a progressive increase in resistance to synthetic compounds. These ectoparasiticides have raised increasing concerns regarding environmental impact, human health, and resistance of ectoparasites to the chemical compounds used as active substances. Given market demands and pressure from international legislation to minimise these constraints, it is essential to investigate safer alternative approaches. These need to demonstrate effectiveness and economic viability while having a lower environmental impact. The importance of proper treatment and control of ectoparasites is a recognised veterinary target with medical repercussions for both animal and human health. Therefore, it is of the upmost importance to know the target properly, for instance, the ectoparasite, including its life cycle and the physiology of the animal on which the parasiticide will be applied. Plants have been used throughout history, initially as a source of food; however, with the knowledge acquired, they began to be used at a medicinal and prophylactic level. In the last 20 years, the interest in using natural compounds (plant extracts and essential oils) to control several ectoparasites in humans and animals has increased. Thus, finding feasible options and consider numerous plants with different properties and active principles is crucial. In addition, it is necessary to collect published scientific data, with the objective to develop alternative ectoparasiticides. Many plants have effective natural defence mechanisms against their aggressors, such as thorns or secondary metabolites. From these metabolites it is possible to develop effective and applicable products for companion and livestock animals. Bioactive compounds, i.e., secondary metabolites that exert toxicological effects on ectoparasites, can be obtained from various parts of plants, such as leaves, stem, flower, and fruit, using extraction methods suited to the objective. Having said this, and since there are numerous plants and therefore a wide variety of bioactive compounds, it is essential to understand the mode of action of each one to better suit the life cycle of the ectoparasite to be controlled. In addition, comprehensive knowledge and chemotype of the selected plant species must be available to ensure less variability in chemical profiles so that the final product mode of action is predictable. One of the main categories of bioactive compounds that contribute to the control of ectoparasites are terpenes and some alkaloids. There are already some plant-derived products whose mode of action of their bioactive compounds is already known. However, it should be noted that there is a significant lack of in vitro and in vivo tests evaluating the efficacy and mode of action of most compounds extracted from different plant species. A sustainable option is to review the knowledge of millenary civilisations about plants and learn about their properties to prevent and combat parasites. Using them efficiently has remained in some populations; however, there is a tendency to be lost due to easy access to other conventional medicine medicines. Ethnobotany studies the way people use plant resources and the relationship between man and plants and is an excellent procedure for bringing together this type of traditional knowledge. Data collection is often carried out with people through interviews or observation, which are the most recurrent ways of recording the knowledge of the population. This type of study paradigm was performed by Professor Doctor Noémia Farinha and Professor Doctor Orlanda Póvoa from Instituto Politécnico de Portalegre – Escola Superior Agrária de Elvas, between July 2011 and April 2012 in Alentejo. This study was carried out with the primary aim to survey the use of plants in the treatment of animals and, secondarily, in humans, using interviews to obtain information on the traditional use of various plant species from different families. Considering the main aim of this dissertation: to produce a hypothetical ectoparasiticide product based on plant extracts, to be used on dogs and some livestock, using the data kindly provided by both professors. Raw data were reviewed and analysed during this dissertation. Thus, the information contained in the interviews was selected: the answers that mentioned ectoparasites and then application in Canidae and/or some livestock were chosen. Furthermore, plants mentioned in more than one interview were picked, analysed, and researched for parasiticidal potential. After analysing the ectoparasiticide potential of the different selected plants, it is suggested that an ectoparasiticide be prepared with extracts of Juglans regia, Daphne gnidium and Ruta graveolens. The proposed product uses isopropanol and water as solvents, thus being a hydroalcoholic excipient, which allows the use of different plant extracts, predominantly alcoholic and hydroalcoholic, with a spot-on/pour-on application mode, using a polylactic acid packaging. In order to place an ectoparasiticide on the market, several studies will be required to formulate the product. Additional testing will also be essential to respond to the various points of the European Public Assessment Report (EPAR). However, several tests are presented, being essential to perform them, to obtain the necessary information and consequently understand if the product proposed is viable in terms of efficacy and safety for the animal where it will be applied, as well as for who uses it and for the environment. It should be noted the lack of data on some plant species, especially those that are restricted to Portugal, making it impractical to corroborate the information of some data collected in the interviews. Furthermore, the lack of toxicological data prevented, in many cases, an accurate evaluation of the possible use and associated risks, just as the lack of data on the mode of action did not allow to evaluate the effectiveness. This dissertation aims to highlight the benefits and possibilities of using plant-derived products as ectoparasiticides. In short, it is possible to use these products in a prophylactic way assisting in the control of infestations with a lower environmental impact, with low toxicity to mammals, and circumventing the problems related to resistance to synthetic ectoparasiticides.
The domestication of animals has been part of history for several decades and is still very present today. Currently, companion animals have very significant importance in human life. Approximately 70 million European families have at least one of these animals. Additionally, we are facing an increase in livestock to meet the food needs of the growing world population. Unfortunately, one of the negative aspects that have arisen, and has continued to occur, from these human/animal interactions is the increase in parasite infestations and, consequently, the rise in parasitism in humans and animals. In recent years, spending on animal healthcare has increased significantly worldwide. According to data from the European Scientific Counsel Companion Animal Parasites (ESCCAP), parasiticide account for 46% of the animal health market, whose largest segment is ectoparasiticides. Parasiticides have been used in parasite control since the 1920s, with ectoparasiticides being responsible for managing ectoparasites in companion animals and livestock. The use of ectoparasiticides reduces discomfort as well as the possibility of disease transmission. Parasites can be vectors of pathogens and responsible for the transmission of viruses, bacteria, helminths, and protozoa. In some cases, the transmission of microorganisms between animals and humans may occur, called zoonosis, which further highlights the need to effectively control ectoparasites, as they may represent a problem to public health. Moreover, we are currently facing a progressive increase in resistance to synthetic compounds. These ectoparasiticides have raised increasing concerns regarding environmental impact, human health, and resistance of ectoparasites to the chemical compounds used as active substances. Given market demands and pressure from international legislation to minimise these constraints, it is essential to investigate safer alternative approaches. These need to demonstrate effectiveness and economic viability while having a lower environmental impact. The importance of proper treatment and control of ectoparasites is a recognised veterinary target with medical repercussions for both animal and human health. Therefore, it is of the upmost importance to know the target properly, for instance, the ectoparasite, including its life cycle and the physiology of the animal on which the parasiticide will be applied. Plants have been used throughout history, initially as a source of food; however, with the knowledge acquired, they began to be used at a medicinal and prophylactic level. In the last 20 years, the interest in using natural compounds (plant extracts and essential oils) to control several ectoparasites in humans and animals has increased. Thus, finding feasible options and consider numerous plants with different properties and active principles is crucial. In addition, it is necessary to collect published scientific data, with the objective to develop alternative ectoparasiticides. Many plants have effective natural defence mechanisms against their aggressors, such as thorns or secondary metabolites. From these metabolites it is possible to develop effective and applicable products for companion and livestock animals. Bioactive compounds, i.e., secondary metabolites that exert toxicological effects on ectoparasites, can be obtained from various parts of plants, such as leaves, stem, flower, and fruit, using extraction methods suited to the objective. Having said this, and since there are numerous plants and therefore a wide variety of bioactive compounds, it is essential to understand the mode of action of each one to better suit the life cycle of the ectoparasite to be controlled. In addition, comprehensive knowledge and chemotype of the selected plant species must be available to ensure less variability in chemical profiles so that the final product mode of action is predictable. One of the main categories of bioactive compounds that contribute to the control of ectoparasites are terpenes and some alkaloids. There are already some plant-derived products whose mode of action of their bioactive compounds is already known. However, it should be noted that there is a significant lack of in vitro and in vivo tests evaluating the efficacy and mode of action of most compounds extracted from different plant species. A sustainable option is to review the knowledge of millenary civilisations about plants and learn about their properties to prevent and combat parasites. Using them efficiently has remained in some populations; however, there is a tendency to be lost due to easy access to other conventional medicine medicines. Ethnobotany studies the way people use plant resources and the relationship between man and plants and is an excellent procedure for bringing together this type of traditional knowledge. Data collection is often carried out with people through interviews or observation, which are the most recurrent ways of recording the knowledge of the population. This type of study paradigm was performed by Professor Doctor Noémia Farinha and Professor Doctor Orlanda Póvoa from Instituto Politécnico de Portalegre – Escola Superior Agrária de Elvas, between July 2011 and April 2012 in Alentejo. This study was carried out with the primary aim to survey the use of plants in the treatment of animals and, secondarily, in humans, using interviews to obtain information on the traditional use of various plant species from different families. Considering the main aim of this dissertation: to produce a hypothetical ectoparasiticide product based on plant extracts, to be used on dogs and some livestock, using the data kindly provided by both professors. Raw data were reviewed and analysed during this dissertation. Thus, the information contained in the interviews was selected: the answers that mentioned ectoparasites and then application in Canidae and/or some livestock were chosen. Furthermore, plants mentioned in more than one interview were picked, analysed, and researched for parasiticidal potential. After analysing the ectoparasiticide potential of the different selected plants, it is suggested that an ectoparasiticide be prepared with extracts of Juglans regia, Daphne gnidium and Ruta graveolens. The proposed product uses isopropanol and water as solvents, thus being a hydroalcoholic excipient, which allows the use of different plant extracts, predominantly alcoholic and hydroalcoholic, with a spot-on/pour-on application mode, using a polylactic acid packaging. In order to place an ectoparasiticide on the market, several studies will be required to formulate the product. Additional testing will also be essential to respond to the various points of the European Public Assessment Report (EPAR). However, several tests are presented, being essential to perform them, to obtain the necessary information and consequently understand if the product proposed is viable in terms of efficacy and safety for the animal where it will be applied, as well as for who uses it and for the environment. It should be noted the lack of data on some plant species, especially those that are restricted to Portugal, making it impractical to corroborate the information of some data collected in the interviews. Furthermore, the lack of toxicological data prevented, in many cases, an accurate evaluation of the possible use and associated risks, just as the lack of data on the mode of action did not allow to evaluate the effectiveness. This dissertation aims to highlight the benefits and possibilities of using plant-derived products as ectoparasiticides. In short, it is possible to use these products in a prophylactic way assisting in the control of infestations with a lower environmental impact, with low toxicity to mammals, and circumventing the problems related to resistance to synthetic ectoparasiticides.
Description
Tese de mestrado, Regulação e Avaliação do Medicamento e Produtos de Saúde, 2021, Universidade de Lisboa, Faculdade de Farmácia.
Keywords
Ectoparasites Ectoparasiticides Ethnobotany Plant-derived products Teses de mestrado - 2021