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Advisor(s)
Abstract(s)
Nos últimos anos tem vindo a aumentar o interesse pelos produtos naturais, como é o caso das plantas medicinais e aromáticas, devido ao seu amplo espetro de ação na indústria alimentar, cosmética e farmacêutica e na medicina popular. As plantas aromáticas e de uso medicinal são utilizadas pelo Homem desde a antiguidade devido às suas propriedades terapêuticas. A partir destas plantas obtêm-se óleos essenciais, cujas atividades antimicrobiana e antioxidante estão descritas em inúmeros trabalhos. Estas propriedades têm adquirido destaque nas últimas décadas devido ao aumento da resistência bacteriana aos antibióticos disponíveis no mercado e à toxicidade apresentada pelos antioxidantes sintéticos.
A Segurelha (Satureja montana), incluída botanicamente na família Lamiaceae, é uma planta aromática frequentemente usada como tempero, estando também referido o seu uso na medicina tradicional. Tal deve-se a propriedades tais como anti-inflamatória, analgésica, antidiabética, anti-hipercolesterolémica, entre outras, as quais podem estar associadas a vários compostos, principalmente os presentes nos óleos essenciais os quais possuem um forte caráter terpénico, geralmente fenólico.
Este trabalho pretendeu ser um contributo para um melhor conhecimento da composição química e bioatividade da planta aromática Satureja montana, tendo-se estudado o óleo essencial e diferentes extratos polares. No que respeita à fração apolar, foi estudada a composição química por GC-MS de uma amostra de óleo essencial extraída por sistema Clevenger e de uma amostra comercial. Para ambas, procedeu-se à avaliação da atividade antimicrobiana pelo método da macrodiluição em caldo. Foram preparados dois extratos (hidroetanólico e decocção) e avaliados quanto ao teor total de compostos fenólicos, de flavonoides e atividade antioxidante por três métodos distintos. Os extratos foram ainda incorporados em hidrogéis, os quais foram avaliados quanto às suas propriedades antioxidantes e antimicrobianas.
Verificou-se a ocorrência de teores superiores de fenóis totais e flavonoides no extrato decocção comparativamente ao extrato hidroetanólico, bem como superior capacidade antioxidante do extrato hidroetanólico, expressa em capacidade captadora do radical DPPH, poder redutor e inibição da descoloração do β-caroteno. No que respeita à atividade antimicrobiana, ambos os óleos essenciais apresentaram atividade bactericida face a todos os microrganismos estudados, tendo o óleo extraído em Clevenger demonstrado melhores resultados. Os hidrogéis preparados com a incorporação de extrato hidroetanólico e decocção demonstraram atividade antioxidante e antimicrobiana, sugerindo que a utilização destes extratos pode ser uma potencial alternativa a antioxidantes e/ou conservantes sintéticos neste tipo de produtos.
Conclui-se, desta forma, que a Segurelha pode ser uma potencial fonte de antimicrobianos e antioxidantes naturais de interesse para diferentes indústrias.
In recent years, interest in natural products has increased, such as medicinal and aromatic plants, due to their wide range of action in the food, cosmetic and pharmaceutical industry and in popular medicine. Aromatic and medicinal plants have been used by man since ancient times due to their therapeutic properties. Essential oils are obtained from these plants, whose antimicrobial and antioxidant activities are described in numerous studies. These properties have gained prominence in recent decades due to the increase in bacterial resistance to antibiotics available on the market and the toxicity presented by synthetic antioxidants. Segurelha (Satureja montana), botanically included in the Lamiaceae family, is an aromatic plant often used as a spice, and its use in traditional medicine is also mentioned. This is due to properties such as anti-inflammatory, analgesic, anti-diabetic, anti- hypercholesterolemic, among others, which can be associated with several compounds, mainly those present in essential oils that have a strong terpenic character, generally phenolic. This work intended to be a contribution to a better knowledge of the chemical composition and bioactivity of the aromatic plant Satureja montana, having studied the essential oil and different polar extracts. Regarding the nonpolar fraction, the chemical composition was studied by GC-MS of a sample of essential oil extracted by Clevenger system and a commercial sample. For both, the antimicrobial activity was evaluated using the broth macrodilution method. Two extracts were prepared (hydroethanolic and decoction) and evaluated for the total content of phenolic compounds, flavonoids and antioxidant activity by three different methods. The extracts were also incorporated into hydrogels, which were evaluated for their antioxidant and antimicrobial properties. Higher levels of total phenols and flavonoid were found in the decoction extract compared to the hydroethanolic extract, as well as the superior antioxidant capacity of the hydroethanolic extract, expressed in the capacity to capture the DPPH radical, reducing power and inhibition of β-carotene discoloration. With regard to antimicrobial activity, both essential oils showed bactericidal activity in relation to all the microorganisms studied, with the oil extracted in Clevenger showing better results. Hydrogels prepared with the incorporation of hydroethanolic extract and decoction showed antioxidant and antimicrobial activity, suggesting that the use of these extracts may be a potential alternative to antioxidants and/or synthetic preservatives in this type of products. It is concluded, therefore, that Segurelha can be a potential source of antimicrobials and natural antioxidants of interest to different industries.
In recent years, interest in natural products has increased, such as medicinal and aromatic plants, due to their wide range of action in the food, cosmetic and pharmaceutical industry and in popular medicine. Aromatic and medicinal plants have been used by man since ancient times due to their therapeutic properties. Essential oils are obtained from these plants, whose antimicrobial and antioxidant activities are described in numerous studies. These properties have gained prominence in recent decades due to the increase in bacterial resistance to antibiotics available on the market and the toxicity presented by synthetic antioxidants. Segurelha (Satureja montana), botanically included in the Lamiaceae family, is an aromatic plant often used as a spice, and its use in traditional medicine is also mentioned. This is due to properties such as anti-inflammatory, analgesic, anti-diabetic, anti- hypercholesterolemic, among others, which can be associated with several compounds, mainly those present in essential oils that have a strong terpenic character, generally phenolic. This work intended to be a contribution to a better knowledge of the chemical composition and bioactivity of the aromatic plant Satureja montana, having studied the essential oil and different polar extracts. Regarding the nonpolar fraction, the chemical composition was studied by GC-MS of a sample of essential oil extracted by Clevenger system and a commercial sample. For both, the antimicrobial activity was evaluated using the broth macrodilution method. Two extracts were prepared (hydroethanolic and decoction) and evaluated for the total content of phenolic compounds, flavonoids and antioxidant activity by three different methods. The extracts were also incorporated into hydrogels, which were evaluated for their antioxidant and antimicrobial properties. Higher levels of total phenols and flavonoid were found in the decoction extract compared to the hydroethanolic extract, as well as the superior antioxidant capacity of the hydroethanolic extract, expressed in the capacity to capture the DPPH radical, reducing power and inhibition of β-carotene discoloration. With regard to antimicrobial activity, both essential oils showed bactericidal activity in relation to all the microorganisms studied, with the oil extracted in Clevenger showing better results. Hydrogels prepared with the incorporation of hydroethanolic extract and decoction showed antioxidant and antimicrobial activity, suggesting that the use of these extracts may be a potential alternative to antioxidants and/or synthetic preservatives in this type of products. It is concluded, therefore, that Segurelha can be a potential source of antimicrobials and natural antioxidants of interest to different industries.
Description
Keywords
Plantas aromáticas Satureja montana Fenóis totais Flavonoides Atividade antioxidante Atividade antimicrobiana Hidrogéis