Atividade anti-micobacteriana e estudo estrutural de diterpenos de halimano e labdano obtidos a partir de plectranthus ornatus codd.
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2021
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Os produtos naturais constituem uma fonte única de compostos protótipo para o desenvolvimento de novos fármacos. Existem vários relatos de diterpenos isolados de Plectranthus spp. com atividade tuberculostática interessante. P. ornatus Codd. tem sido utilizado na Medicina Tradicional por exemplo como anti-infecioso em determinadas regiões do Brasil. Em trabalhos anteriores, foi possível isolar em grande quantidade um diterpeno com esqueleto de halimano e outro de esqueleto de labdano de P. ornatus Codd. Neste trabalho, avaliou-se a atividade anti-micobacteriana destes compostos com uma estirpe não virulenta de Mycobacterium smegmatis, a sua citotoxicidade e a concentração inibitória mínima. Pelo método de ultrassons, foi possível obter um extrato acetónico da planta medicinal P. ornatus com um rendimento de 7,08% (m/m). O composto diterpénico de esqueleto de halimano foi isolado a partir desse extrato, obtendo-se 5,3 mg de composto puro. O produto foi novamente recristalizado, sendo possível determinar a sua estrutura através de dados de difração de raios-X em monocristal (SCXRD). A caraterização estrutural foi complementada com espectroscopia de infravermelhos com transformada de Fourier (FTIR) e a estabilidade térmica do composto foi aferida através de microscopia de placa quente (HSM).
Natural products are a unique source of lead compounds for the development of new drugs. There are several reports of isolated diterpenes from Plectranthus spp. with interesting tuberculostatic activity. P. ornatus Codd. has been used in traditional medicine as an anti-infective in certain regions of Brazil. In previous works, it was possible to isolate a large quantity of halimane and labdane skeletons from P. ornatus Codd. In this work, the anti-mycobacterial activity of these compounds was evaluated with a non-virulent strain Mycobacterium smegmatis, its cytotoxicity and its minimum inhibitory concentration. Using the ultrasound method, it was possible to obtain an acetonic extract of the entire medicinal plant P. ornatus with a yield of 7.082% (w/w). The prototype haliman compound was isolated from this extract, obtaining 5.3 mg of pure compound. The product was recrystallized again, being possible to determine its structure through single crystal X-ray diffraction data (SCXRD). The structural characterization was complemented with Fourier Transform Infrared Spectroscopy (FTIR) and the thermal stability of the compound was measured using hot stage microscopy (HSM).
Natural products are a unique source of lead compounds for the development of new drugs. There are several reports of isolated diterpenes from Plectranthus spp. with interesting tuberculostatic activity. P. ornatus Codd. has been used in traditional medicine as an anti-infective in certain regions of Brazil. In previous works, it was possible to isolate a large quantity of halimane and labdane skeletons from P. ornatus Codd. In this work, the anti-mycobacterial activity of these compounds was evaluated with a non-virulent strain Mycobacterium smegmatis, its cytotoxicity and its minimum inhibitory concentration. Using the ultrasound method, it was possible to obtain an acetonic extract of the entire medicinal plant P. ornatus with a yield of 7.082% (w/w). The prototype haliman compound was isolated from this extract, obtaining 5.3 mg of pure compound. The product was recrystallized again, being possible to determine its structure through single crystal X-ray diffraction data (SCXRD). The structural characterization was complemented with Fourier Transform Infrared Spectroscopy (FTIR) and the thermal stability of the compound was measured using hot stage microscopy (HSM).
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Orientação: Patrícia Dias Rijo
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MESTRADO INTEGRADO EM CIÊNCIAS FARMACÊUTICAS, CIÊNCIAS FARMACÊUTICAS, PLANTAS MEDICINAIS, PHARMACEUTICAL SCIENCES, MEDICINAL PLANTS