ABSTRACT
The methanolic extracts of Pterocaulon alopecuroides and Pterocaulon angustifolium were assayed for antibacterial activity and biofilm formation inhibition of four community-acquired-MRSA isolates representative of ST30 t975, ST30 t021, ST5 t311, and ST4335 t008 clones that are responsible for invasive infections in Paraguayan children. Both Pterocaulon extracts showed significant antibacterial activity with a minimum inhibitory concentration of 200 µg/mL against the four isolates. P. angustifolium showed inhibition of biofilm formation for the four isolates, whereas P. alopecuroides showed inhibition for three of them. The chemical constituents were identified by liquid chromatography coupled to tandem mass spectrometry. Phenolic compounds were detected in the two species as well as coumarins. These results showed that these plants are sources of compounds with activity against MRSA.
Subject(s)
Asteraceae , Methicillin-Resistant Staphylococcus aureus , Child , Humans , Methanol , Asteraceae/chemistry , Microbial Sensitivity Tests , Anti-Bacterial Agents/pharmacology , Anti-Bacterial Agents/chemistry , Plant Extracts/pharmacology , BiofilmsABSTRACT
Pterocaulon alopecuroides (Lamark) De Candolle and Bidens segetum Mart. ex Colla are two species belonging to the Asteraceae family. Extracts from those two species were evaluated to their cytotoxic, antioxidant and antiviral activities. All the extracts assayed have shown a very high cytotoxity against RBL-2H3 cell line. The antioxidant assay pointed out a really high activity of the ethyl acetate extracts for B. segetum and P. alopecuroides. This can be partially explained due to the high content of coumarins, at least for P. alopecuroides. None of the total ethanol extracts from B. segetum showed significant activity against the two strains of Herpes simplex virus (Types 1 and 2 resistant to acyclovir). P. alopecuroides ethanol extract was also inactive against the Herpes simplex virus type 1 resistant to acyclovir. However, this extract presented inhibitory activity against the Herpes simplex virus type 2 resistant to acyclovir. From the ethanol crude extract of P. alopecuroides, it was possible to isolate 7-(2',3'-dihidroxy-3'-methylbutyloxy)-6-methoxycoumarin, which was tested in the same conditions, showing a viral inhibitory rate almost twice bigger than the P. alopecuroides sample for HSV-2-ACVr. The coumarin was also active against HSV-1-ACVr. Those results provide further evidence of the importance of Pterocaulon alopecuroides and Bidens segetum as medicinal plants.
Pterocaulon alopecuroides (Lamark) De Candolle e Bidens segetum Mart. ex Colla são duas espécies pertencentes à família Asteraceae. Os extratos dessas duas espécies foram avaliados quanto às suas atividades citotóxica, antioxidante e antiviral. Todos os extratos analisados apresentaram citotoxidade muito alta contra linhagens de células RBL-2H3. O ensaio de atividade antioxidante demonstrou uma alta atividade das frações em acetato de etila de B. segetum e P. alopecuroides. Isso pode ser parcialmente explicado pelo alto conteúdo de cumarinas, ao menos para P. alopecuroides. Nenhum dos extratos etanólicos totais de B. segetum mostraram atividade significativa contra o vírus Herpes simplex (Tipos 1 e 2 resistentes ao aciclovir). O extrato etanólico de P. alopecuroides também foi inativo contra o vírus Herpes simplex tipo 1 resistente ao aciclovir. Entretanto, este extrato apresentou atividade inibitória contra o vírus Herpes simplex tipo 2 resistente ao aciclovir. Do extrato etanólico bruto de P. alopecuroides foi possível isolar a 7-(2',3'-dihidroxi-3'-metilbutiloxi)-6-metoxicumarina, a qual foi testada nas mesmas condições, demonstrando um índice de inibição viral quase duas vezes maior do que o da amostra de P. alopecuroides para HSV-2-ACVr. A cumarina tabém foi ativa contra HSV-1-ACVr. Esses resultados evidenciam a importância de Pterocaulon alopecuroides e Bidens segetum como plantas medicinais.
