Chemical analysis using liquid chromatography coupled to mass spectrometry and cytotoxic activity of Rhinella jimi toad venom

The diversity of compounds produced by amphibians in their glands secretions are amazingly high. It is a fascinating source of active compounds, such as peptides, alkaloids and bufadienolides. Since many compounds have been already isolated, it is crucial to avoid the repeated isolation of known compounds and to promote the discovery of novel ones. HPLC-ESI-Q-TOF-MS have been used to facilitates the discrimination of novel from known compounds in extracts. This work has the objective to identify constituents of methanolic extract from toad venom of R. jimi using HPLC-ESI-IT-MS and to evaluate the cytotoxic activity in tumor cell lines.
The Extracted Ion Chromatogram (XIC) of methanolic extract in positive mode was obtained in HPLC-ESI-IT-MS (Amazon X, Bruker) and based on fragmentation pattern and comparation to literature. There were tentative identified twenty-eight compounds: marinobufagin (1), bufalin (2), telocinobufagin (3), bufarenogin (4), ψ-Bufarenogin (5), adipoyl arginine (6), pimeloyl arginine (7), suberoyl arginine (8), azelaoyl arginine (9), dehydrobufotenin (10), bufotenidin (11), diacids argininyl derivatives of resibufagin (12-13), marinobufagin (14-18), bufotalinin (19), bufalin (20-21), telocinobufagin (22-24), bufarenogin (25-26) and ψ-Bufarenogin (27-28) (Figure 1). The methanolic extract presented better cytotoxic activity for the tumor cell lines NCI-460, HEK-293 and SNB19 when compared to the control doxorrubicin.
By HPLC-ESI-MS there were identified 28 compounds in the extract which demonstrated good cytotoxicity action against human tumor cell lines. These results can be used to promote the isolation of the compounds and verify which one has this good activity.