Abstract

Antioxidant capacity, phenolic content, antimicrobial and cytotoxic properties of extracts and fractions from flowers and fruits of G. uruguensis were evaluated. Total phenolic content ranged between 406.8 ± 20.47 and 57.98 ± 1.734 gallic acid equivalent in mg g^-1 (mg GAE g^-1) samples. Ethyl acetate and butanol fractions from flowers had the greatest rates in phenolic content and antioxidant activity in 1,1-diphenyl-2-picrylhydrazyl (DPPH) and thiobarbituric acid reactive substances (TBARS) assays. Pearson´s coefficient showed a strong association between total phenolic compounds in DPPH (r = - 0.83, p < 0.01) and TBARS (r = 0.85, p < 0.01). Eleven out of the 12 samples tested were toxic in the brine shrimp assay (LC50 < 100 µg mL^-1). Antimicrobial susceptibility profile revealed flower remaining fraction and fruit extract with moderate activity against Enterococcus faecalis. Results indicate that G. uruguensis is a good source of compounds with antioxidant and cytotoxic activities. Further studies to identify compounds causing these activities are recommended.

Key words: Guettarda uruguensis, total phenolics, antioxidant activity, antimicrobial, brine shrimp lethality.