In recent years the strawberry tree (Arbutus unedo L.) is being gradually replaced by other species with
higher economic value. With the ultimate goal of selecting superior genotypes, the present work was
initiated to study the antioxidant and antimicrobial activities, and total phenolic content in 19 different
genotypes of A. unedo leaves from the Trás-os-Montes region of Portugal.
The genotype Braganc¸ a 1 contains higher total phenolic content (215.0 mg GAE/gextract) whereas the
Vila Boa 4 genotype shows lower total phenolic content (148.0 mg GAE/gextract). In both methods tested
to evaluate the antioxidant activity, Vila Verde and Donai displayed the highest antioxidant capacity
(EC50 values of 0.088 and 0.090 mg/mL, respectively, for DPPH; EC50 values of 0.233 and 0.245 mg/mL,
respectively, for reducing power assay) while Vila Boa 2 reported the lowest antioxidant potential (EC50
values of 0.142 and 0.378 mg/mL, respectively, in DPPH and reducing power methods). Linear negative
correlations were established between the total phenol contents and the EC50 values for both of the
antioxidant activity methods tested. Preliminary assays for antimicrobial potential showed that extracts
from A. unedo leaves display antibacterial activity, with MIC values of 1 and 5 mg/mL for some Grampositive
and Gram-negative bacteria, respectively. Taken together, the results suggest that A. unedo leaves
are a potential source of natural compounds with valuable bioactive properties that could be explored
by the pharmaceutical, chemical and food industries.
