title: The cutaneous secretion of the casque-headed tree frog Corythomantis greeningi: Biochemical characterization and some biological effects.
abstract: Corythomantis greeningi is a tree-frog endemic of the Brazilian semi-arid (Caatinga), mainly characterized by the flat, mineralized and spiny head, which is associated with phragmotic habits. It is already known that the skin secretion of this amphibian from both head and body is quite toxic and is used as an efficient chemical defence against predators. However, the biochemical characteristics and pharmacological effects of this secretion are still very little studied. We have tested the crude skin secretion, as well as the ten major fractions obtained by RP-HPLC for nociceptive and edema activity and for in vitro cytotoxicity using murine models. SDS-PAGE analyses demonstrated that the majority of proteins ranging through the gel lie between 55 and 30 kDa. LC-MS analysis showed multiple low molecular mass molecules (200-500 Da), which are consistent with masses of alkaloids and steroids. The crude skin secretion was able to induce fast and persistent edema accompanied by intense dose-dependent nociception. From the 10 tested fractions, five induced both edema and nociception, six fractions were able to induce only edema (80-170% control), and seven fractions induced only nociception (15-30 times compared to control). In addition, inhibition of cell growth (IC50) was demonstrated in murine fibroblasts and melanoma cells. From the data obtained, we confirmed that the skin secretion of C. greeningi is very toxic and is rich in compounds able to directly provoke local inflammation and nociception. Such characteristics are important as part of the chemical defensive repertory of this species.
authors.affiliation: Laboratory of Cell Biology, Butantan Institute, Av. Vital Brasil 1500, 05503-000, São Paulo, SP, Brazil.
authors.forename: Vanessa A
authors.initials: VA
authors.lastname: Mendes
authors.affiliation: Laboratory of Immunopathology, Butantan Institute, Av. Vital Brasil 1500, 05503-000, São Paulo, Brazil.
authors.forename: Katia C
authors.initials: KC
authors.lastname: Barbaro
authors.affiliation: Laboratory of Biochemistry and Biophysics, Butantan Institute, Av. Vital Brasil 1500, 05503-000, São Paulo, Brazil.
authors.forename: Juliana M
authors.initials: JM
authors.lastname: Sciani
authors.affiliation: Laboratory of Cell Biology, Butantan Institute, Av. Vital Brasil 1500, 05503-000, São Paulo, SP, Brazil.
authors.forename: Ruth C
authors.initials: RC
authors.lastname: Vassão
authors.affiliation: Laboratory of Biochemistry and Biophysics, Butantan Institute, Av. Vital Brasil 1500, 05503-000, São Paulo, Brazil.
authors.forename: Daniel C
authors.initials: DC
authors.lastname: Pimenta
authors.affiliation: Laboratory of Cell Biology, Butantan Institute, Av. Vital Brasil 1500, 05503-000, São Paulo, SP, Brazil.
authors.forename: Carlos
authors.initials: C
authors.lastname: Jared
authors.affiliation: Laboratory of Cell Biology, Butantan Institute, Av. Vital Brasil 1500, 05503-000, São Paulo, SP, Brazil. Electronic address: marta.antoniazzi@butantan.gov.br.
authors.forename: Marta M
authors.initials: MM
authors.lastname: Antoniazzi
mesh_terms: D000818:Animals; D001001:Anura; D004487:Edema / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D008297:Male; D059225:Nociception; D012867:Skin / Q000378:metabolism*
keywords: Amphibia; Amphibian skin; Anura; Bioactive compounds; Corythomantis; Granular glands; Poison