Potencial antioxidante e antimicrobiano de espécies da família Asteraceae

Abstract

Asteraceae species have been largely used in folk medicine for several therapeutic purposes. Thus, the aim of this work was to investigate the in vitro antimicrobial and antioxidant activities of methanol extracts from plants belonging to the Asteraceae family, most of which are commonly used in traditional medicine. Chemical prospecting of extracts was also performed. The antimicrobial activity was evaluated through the broth microdilution susceptibility method and the antioxidant activity was determined through DPPH assay. Leaf extract of Baccharis dracunculifolia presented a significant antimicrobial activity against Pseudomonas aeruginosa,Bacillus cereus and Cryptococcus neoformans (0.005, 0.005 and 0.039 mg mL-1 MIC, respectively). Leaf extracts of Bidens segetum and Matricaria chamomilla were selective for Shigella sonnei and P. aeruginosa (0.005 and 0.078 mg mL-1 MIC, respectively). On the other hand, Acanthospermun australe and Baccharis trimera leaves only showed significant activity against Candida albicans (0.039 mg mL-1 MIC), while Taraxacum officinale leaves were active against both yeasts, with 0.039 mg mL-1 MIC. As regards antioxidant activity, extracts of B. dracunculifolia and T. officinale leaves and B. segetum inflorescences presented significant activity, with 5, 5 and 4 µg mL-1 IC50, respectively. The chemical prospecting identified the presence of flavonoids, terpenes and other compounds which may be responsible for the observed activities.