ANTIFUNGAL ACTIVITY OF NEW PEPTIDES FROM SKIN SECRETION OF THE SOUTH AMERICAN FROG Leptodactylus pentadactylus

CORDEIRO-SOUSA J. (1), FONTENELE-BERTO R. (1), OLIVEIRA, R. G. S. (1), REBOUÇAS JR J. P. (1), HONÓRIO JR J.E.R. (2), OLINDA A. C. C. (1), CARVALHO I. F. (1), ADED DA SILVA P. (1), CARDI B. A. (1,2), FONTENELE-CARDI N. C. (3), CORDEIRO R. A. (3), PIMENTA D. C. (4), ROCHA M. F. G (5), CARVALHO K. M. (1)

(1) Lab. de Toxinologia e Farmacologia Molecular, ISCB/UECE; (2) Lab. de A. Peçonhentos, ISCB/UECE; (3) Hosp. São José de Doenças Infecciosas, Ceará; (4) Centro de Toxinologia Aplicada (CAT/CEPID – FAPESP), Inst. Butantan; (5) Lab. Micologia, ISCB/UECE

Several animals like some plants defend themselves against invading pathogenic microorganisms producing cationic antimicrobial peptides. The magainins (Xenopus laevis) and dermaseptin (Phyllomedusa sauvagei) are exemple of antifungal peptides isolated from skin frog secretions. The aim of the present work was identify antifungal activity of compounds present in gland secretion of L. pentadactylus skin. Adult specimens of L. pentadactylus were collected in Paraipaba (Ceará, Brazil) and maintained in captivity. The secretion from their cutaneous glands was obtained by mild electrical stimulation (2-7 V), collected, lyophilized and kept at -25ºC. The secretion was purified by HPLC with a C18 column (25X250mm), eluted with a flow of 4,5ml/min and a 0-80% linear gradient of acetonitrile. Fractions were manually collected and lyophilized. The purified fractions were submitted to mass spectrometry analysis using MALDI-TOF technique. To verify antifungal activity, all fractions were tested by incubating with Candida albicans, C. tropicalis and filamentous fungi Microsporum canis and Trichophyton rubrum (Nat. Committee for Clinical Lab. Standards, 2002). No fractions exhibited antifungal activity against yeast C. albicans and C. tropicalis. However, incubations with filamentous fungi showed five fractions capable to inhibit 100% of the in vitro growth at millimolar level. The results show active peptides with 1268, 1476, 2066, 2008, 1747 and 1899 Da. The chemical characterization of these compounds is in progress. Understanding the structural design of these new peptides may contribute to the improvement of development of antifungal drugs for future therapeutic uses.

KEY WORDS: Leptodactylus, antifungal peptides, antimicrobial peptides

FINANCIAL SUPPORT: FUNCAP, CAPES, CNPq

CORRESPONDENCE TO: carvalhokris@gmail.com