This work describes the isolation of an active flavonoid fraction and identification of isorhamnetin 3-O-β-D-(6''-acetyl)-galactopyranoside from flowers of B. perennis, and also the evaluation of anticholinesterase (AChE) activity of ethanolic extract from flowers (EEF) and the active fraction. The chemical structure of the flavonoid was defined on the basis of spectroscopic ¹H NMR, IR and UV data. EEF or flavonoid reduces AChE activity in vivo, while flavonoid also reduces AChE activity in vitro, showing a value of 1.49 mM for 50% inhibitory concentration (IC50), suggesting potential use as an insecticide or in the treatment of neurodegenerative diseases such as Alzheimer's disease.

Acute toxicity, antioxidant activity in vitro and general pharmacological effects of the flower crude ethanolic extract of Bellis perennis L., Asteraceae, a popular medicine used in South America, were investigated in mice. The oral route LD50 value was found 2.31 g/kg. Oral administration at doses 50, 100 and 150 mg/kg of the extract neither caused significant changes in general behavior nor led to toxic symptoms. Anxiolytic-like properties were studied in the open field test and the possible antidepressant-like actions were evaluated in the forced swimming test (FST). There is a significant decrease in the number of crossings at all dosages mentioned above, but no sedative effects at any dosages when compared to controls. In the FST, the extract dosage of 150 mg/kg was effective in reducing immobility, along with a significant increase in swimming time. The ethanolic extract showed strong antioxidant potential in vitro, through the removal capacity against hydroxyl radicals and nitric oxide as well as prevented the formation of reactive substances to thiobarbituric acid (TBARS). Together, these results indicate that the ethanolic extract has effect on central nervous system, which might due to its antioxidant property, as demonstrated in vitro methods used. These results suggest that some of the components in ethanolic extract of B. perennis, such as alkaloids, phenolic compounds and flavonoids may have antioxidant, anxiolytic and antidepressant-like properties. Additional investigations are in progress.