Abstract

Background and Objective: Lichens are widely used in the traditional medicine of various cultures, highlighting the systematic use of these by pre-Columbian cultures of South America. In this context, the present study intended to describe the antimicrobial activity against Gram-positive and Gram-negative bacteria in addition to in vitro enzymatic inhibition by extracts from the Peruvian lichens Xanthoparmelia tasmanica and Flavopunctelia flaventior. Methodology: The antibacterial activity was evaluated by the broth microdilution method to determinate the Minimum Inhibitory Concentrations (MIC) against Staphylococcus aureus, Enterococcus faecalis, Listeria monocytogenes, Bacillus cereus, Micrococcus luteus, Escherichia coli, Salmonella typhimurium and Pseudomonas aeruginosa as well as their inhibitory effect on alpha-glucosidase and alpha-amylase. Results: The extracts induced a powerful biocidal effect against Gram-positive bacteria, the most susceptible bacterial strain was Micrococcus luteus (MIC = 6.25 mu g mL(-1)). The extract of F. flaventior showed the highest effect on the inhibition of the alpha-glucosidase and alpha-amylase with an IC(50)of 0.34 +/- 0.09 and 0.57 +/- 0.17 mg mL(-1), respectively, the amylase inhibition was better than that produced by acarbose (0.97 +/- 0.08 mg mL(-1)). Conclusion: Current results demonstrated the potent antibacterial activity of lichen in extracts from X. tasmanica and F. flaventior, besides, inhibit carbohydrate digestive enzymes. These properties may be utilized to treat postprandial hyperglycemia and regulate glycemia in diabetic patients.