Chemical and Pharmacological Screening of Rhinella icterica (Spix 1824) Toad Parotoid Secretion in Avian Preparations.

摘要: The biological activity of Rhinella icterica parotoid secretion (RIPS) and some its chromatographic fractions (RI18, RI19, RI23, RI24) was evaluated in the current study. Mass spectrometry these indicated presence sarmentogenin, argentinogenin, (5β,12β)-12,14-dihydroxy-11-oxobufa-3,20,22-trienolide, marinobufagin, bufogenin B, 11α,19-dihydroxy-telocinobufagin, bufotalin, monohydroxylbufotalin, 19-oxo-cinobufagin, 3α,12β,25,26-tetrahydroxy-7-oxo-5β-cholestane-26-O-sulfate, cinobufagin-3-hemisuberate that were identified as alkaloid steroid compounds, addition to marinoic acid N-methyl-5-hydroxy-tryptamine. In chick brain slices, all caused a slight decrease cell viability, also seen with highest concentration RIPS tested. biventer cervicis neuromuscular preparations, four significantly inhibited junctional acetylcholinesterase (AChE) activity. this preparation, only fraction RI23 completely mimicked pharmacological profile RIPS, which included transient facilitation amplitude muscle twitches followed by progressive complete blockade. spectrometric analysis showed consisted predominantly bufogenins, class steroidal compounds known for their cardiotonic mediated digoxin- or ouabain-like action blockade voltage-dependent L-type calcium channels. These findings indicate activities (and RIPS) are probably by: (1) inhibition AChE increases content Ach; (2) neuronal Na+/K+-ATPase, leading blockade; (3) Ca2+ channels, stabilization motor endplate membrane.