title: Antimicrobial activity of the bufadienolides marinobufagin and telocinobufagin isolated as major components from skin secretion of the toad Bufo rubescens.
abstract: The increase in the emergence of antibiotic-resistant microorganisms and difficult to treat infections caused by these pathogens stimulate research aiming the identification of novel antimicrobials. Skin secretion of amphibian contains a large number of biologically active compounds, including compounds that performance defense mechanisms against microorganisms. In the present work, two antimicrobial bufadienolides, telocinobufagin (402.1609 Da) and marinobufagin (400.1515 Da), were isolated from skin secretions of the Brazilian toad Bufo rubescens. The specimens were collected in Brasilia (Distrito Federal, Brazil), the skin secretions extracted by electric stimulation, and submitted to purification by RP-HPLC. The molecular structure and mass determination were done by (1)H and (13)C NMR and mass spectrometry data, respectively. The antimicrobial activity was performed by liquid growth inhibition against Staphylococcus aureus and Escherichia coli. The minimum inhibitory concentrations of telocinobufagin and marinobufagin were, respectively, 64.0 and 16.0 microg/mL for E. coli and both 128 microg/mL for S. aureus. Besides the antimicrobial activity both bufadienolides promoted an increase of the contraction force in isolated frog ventricle strips.
authors.affiliation: Laboratório de Toxinologia, Departamento de Ciências Fisiológicas, Instituto de Ciências Biológicas, Universidade de Brasília, Brasília, DF 70910-900, Brazil.
authors.forename: Geraldino A
authors.initials: GA
authors.lastname: Cunha Filho
authors.forename: Carlos Alberto
authors.initials: CA
authors.lastname: Schwartz
authors.forename: Inês S
authors.initials: IS
authors.lastname: Resck
authors.forename: Maria Márcia
authors.initials: MM
authors.lastname: Murta
authors.forename: Sebastião S
authors.initials: SS
authors.lastname: Lemos
authors.forename: Mariana S
authors.initials: MS
authors.lastname: Castro
authors.forename: Cynthia
authors.initials: C
authors.lastname: Kyaw
authors.forename: Osmindo R
authors.initials: OR
authors.lastname: Pires
authors.forename: José Roberto S
authors.initials: JR
authors.lastname: Leite
authors.forename: Carlos
authors.initials: C
authors.lastname: Bloch
authors.forename: Elisabeth Ferroni
authors.initials: EF
authors.lastname: Schwartz
mesh_terms: D000664:Amphibian Venoms / Q000378:metabolism / Q000633:toxicity*; D000818:Animals; D000900:Anti-Bacterial Agents / Q000302:isolation & purification / Q000633:toxicity*; D001938:Brazil; D002018:Bufanolides / Q000302:isolation & purification / Q000633:toxicity*; D002025:Bufonidae / Q000378:metabolism* / Q000502:physiology; D002316:Cardiotonic Agents / Q000302:isolation & purification / Q000633:toxicity; D002851:Chromatography, High Pressure Liquid; D004926:Escherichia coli / Q000187:drug effects; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D008826:Microbial Sensitivity Tests; D009200:Myocardial Contraction / Q000187:drug effects; D011487:Protein Conformation; D012867:Skin / Q000378:metabolism*; D013211:Staphylococcus aureus / Q000187:drug effects
chemical_list: D000664:Amphibian Venoms; D000900:Anti-Bacterial Agents; D002018:Bufanolides; D002316:Cardiotonic Agents; C093896:marinobufagenin; C009391:telocinobufagin