In vitro cytotoxic, antioxidant and antiviral effects of Pterocaulon alopecuroides and Bidens segetum extracts

Abstract

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.