OBJECTIVE:

To evaluate the antimicrobial activity of extracts obtained from lichenized fungi occurring in Belém campus of Universidade Federal do Pará, Brazil.

MATERIALS AND METHODS:

Lichenic samples of Leptogium sp. and Parmotrema sp. were submitted to organic extraction by cold exhaustion, following the eluotropic series chloroform and acetone. The extracts obtained were tested against strains of Gram-positive, Gram-negative and acid-resistant bacteria, filamentous fungi, and yeast using the disk diffusion method in agar. Paper discs were impregnated with 20 µL of each extract at a concentration of 4 mg/mL and placed on the medium previously inoculated with the test microorganisms. The results were evaluated by the diameter of the inhibition halos around the discs. Then, the extracts were submitted to thin layer ascending chromatography and bioautographic assays to detect the active ingredients.

RESULTS:

There was a higher antimicrobial potential of Parmotrema sp. with inhibition halos ranging from 8 to 12 mm for bacteria and from 8 to 21 mm for fungi. The bacteria Escherichia coli, Klebsiella pneumonia, and Mycobacterium phlei showed higher sensitivity, as they were inhibited by both lichen species. The most sensitive fungi were Trichophyton tonsurans, Microsporum gypseum, and Epidermophyton floccosum.

CONCLUSION:

This study expanded the knowledge about lichenized fungi of the Amazon Region and proved to be feasible to obtain antimicrobial substances capable of inhibiting the growth of bacteria and fungi of medical importance.

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