Evaluation of antioxidant capacity, phenolic content, antimicrobial and cytotoxic properties of Guettarda uruguensis flowers and fruits

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.