Atividade anti-micobacteríana de diterpenos de esqueleto halimano e labdano obtidos de Plectranthus ornatus Codd
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2018
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Edições Universitárias Lusófonas
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Os produtos naturais são uma fonte única de compostos-tipofpara o desenvolvimento de fármacos em química medicinal. Vários diterpenos das espécies Plectranthus foram referidos com actividade tuberculostática interessante, sendo que o P. omatus Codd. é usado como anti-infeccioso em algumas regiões do Brasil. Em trabalhos anteriores, um diterpeno de esqueleto de halimano outro labdano foram isolados a partir de P. ornatus Codd. Neste trabalho, avaliou-se preliminarmente a sua actividade micobacteriana com uma estirpe não virulenta de Mycobacterium smegmatis. A citotoxicidade dos compostos foi testada medindo a libertação de lactato desidrogenase (LDH) não sendo encontrados efeitos citotóxicos consideráveis até 25 ug/mL. Posteriormente, o método de microdiluição foi utilizado para determinar a concentração mínima inibitória (CMI) de M. smegmatis. A CMI>99% para o esqueleto de halimano foi 100 ug/mL e >100 ug/mL para o esqueleto de labdano. De acordo com o nosso conhecimento, este é o primeiro estudo usando diterpenos de esqueleto de halimano e de labdano isolados a partir de P. omatus em ensaios de citotoxicidade em macrófagos, e num ensaio preliminar sobre a sua atividade anti-micobacteriana. Estudos futuros são sugeridos na estirpe virulenta de M. tugerculosis, particularmente para os diterpenos de esqueleto de halimano.
Plectranthus spp. have been reported to have interesting tuberculostatic activity and P. ornatus Codd. has been used in some regions of Brazil as an anti-infective. Previously, diterpenes with halimane and labdane skeletons were isolated in large quantities from P. ornatus Codd. We assessed the anti-mycobacterial activity of these compounds, performing a preliminar assay with the non-virulent strain Mycobacterium smegmatis. The cytotoxicity of the diterpenes with halimane and labdane skeletons was tested with the lactate dehydrogenase assay, where no considerable cytotoxic effects were found up to 25 μg.mL-1. Subsequently, the microdilution method was used to determine the minimum inhibitory concentration (MIC) against M. smegmatis. The MIC that inhibited the growth of the non-virulent mycobacteria by ≥99% was 100 μg.mL-1 for the diterpene with halimane skeleton, whereas for the diterpene with a labdane skeleton was >100 μg.mL-1. To the best of our knowledge, this is the first report on diterpenes with halimane and labdane skeletons isolated from P. ornatus in macrophages cytotoxicity, and in a preliminar assay for anti-mycobacterial activity. Further studies are suggested on M. tuberculosis, particularly for the diterpenes with halimane skeleton.
Plectranthus spp. have been reported to have interesting tuberculostatic activity and P. ornatus Codd. has been used in some regions of Brazil as an anti-infective. Previously, diterpenes with halimane and labdane skeletons were isolated in large quantities from P. ornatus Codd. We assessed the anti-mycobacterial activity of these compounds, performing a preliminar assay with the non-virulent strain Mycobacterium smegmatis. The cytotoxicity of the diterpenes with halimane and labdane skeletons was tested with the lactate dehydrogenase assay, where no considerable cytotoxic effects were found up to 25 μg.mL-1. Subsequently, the microdilution method was used to determine the minimum inhibitory concentration (MIC) against M. smegmatis. The MIC that inhibited the growth of the non-virulent mycobacteria by ≥99% was 100 μg.mL-1 for the diterpene with halimane skeleton, whereas for the diterpene with a labdane skeleton was >100 μg.mL-1. To the best of our knowledge, this is the first report on diterpenes with halimane and labdane skeletons isolated from P. ornatus in macrophages cytotoxicity, and in a preliminar assay for anti-mycobacterial activity. Further studies are suggested on M. tuberculosis, particularly for the diterpenes with halimane skeleton.
Descrição
Biomedical and biopharmaceutical research : jornal de investigação biomédica e biofarmacêutica
Palavras-chave
MEDICINA, CIÊNCIAS FARMACÊUTICAS, CITOXICIDADE, DITERPENOS, PLANTAS, MEDICINE, PHARMACEUTICAL SCIENCES, CYTOTOXICITY, DITERPENES, PLANTS