Antioxidant, antimicrobial, antitopoisomerase and gastroprotective effect of herbal infusions from four Quercus species

Leaves from four species of white oaks (Quercus resinosa, Quercus laeta, Quercus grisea, and Quercus obtusata) were investigated for the evaluation and comparison of their antioxidant, antimicrobial, anti-topoisomerase, and anti-proliferative activities. DPPH and hydroxyl radical scavenging capacities were tested in vitro. Results indicated that aqueous extracts from leaves of Quercus laeta and Q. grisea displayed higher radical scavenging activity, while extracts from Q. grisea and Q. obtusata were more efficient in inhibiting the degradation of deoxyribose, preventing the formation of hydroxyl radicals. Polar extracts showed different degrees of antimicrobial activity, presenting Q. resinosa leaves a broader spectrum. In the anti-topoisomerase assay only Q. resinosa leaves infusions showed activity. The investigation indicates that the biological activity of aqueous extracts from oak leaves promises a more rational and effective application of this resource in the near future.

► Infusions from leaves of Quercus laeta and Q. grisea displayed higher radical scavenging activity.
► Infusions from Q. grisea and Q. obtusata were more efficient in preventing the formation of hydroxyl radicals.
► Infusions from Q. resinosa showed a broader antimicrobial spectrum.
► Q. resinosa leaves infusions showed antitopoisomerase activity.