Author(s): CunhaFilho GA, Resck IS, Cavalcanti BC, Pessoa CO, Moraes MO,
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Abstract Cutaneous secretions of toad species are an important source of bufadienolides, compounds that exhibit interesting structural features and biopharmacological properties. Here we describe the isolation of bufadienolides from the Brazilian toad Rhinella schneideri parotoid glands secretion, including: marinobufagin (1), bufalin (2), telocinobufagin (3), hellebrigenin (4), and the atypical 20S,21R-epoxymarinobufagin (5) besides the widespread beta-sitosterol (6). Starting from natural bufadienolides four derivatives were prepared: 3beta-acetoxy-marinobufagin (7), 3beta-acetoxy-bufalin (8), 3beta-acetoxy-telocinobufagin (9), and 3beta-acetoxy-20S,21R-epoxymarinobufagin (10). The cytotoxic evaluation showed that all natural bufadienolides and their derivatives exhibited moderate to strong activity against human HL-60, SF-295, MDA-MB-435, and HCT-8 cancer cell strains without hemolysis of mouse erythrocytes. The acetylated bufadienolides (7-9) and the epoxide 10 showed lesser peripheral blood lymphocytes (PBLs) inhibitory activity than their precursors, suggesting that chemical modifications on such compounds can play an important role on the modulation of their cytotoxic profile. Copyright 2010 Elsevier Ltd. All rights reserved.
This article was published in Toxicon
and referenced in Pharmaceutica Analytica Acta