Cytotoxic constituents from the skin of the toad Bufo bufo gargarizans

Abstract

To study the chemical composition of the skin of Bufo bufo gargarizans, various chromatographic methods were used in the isolation procedures and the structures of isolated compounds were determined based on NMR and MS analysis. As a result, two new compounds were isolated from its ethanolic extract and characterized as N-[2-hydroxy-2-(4-hydroxyphenyl)ethyl]-N-methylurea (1) and 19-oxocinobufotalin 3-adipoylarginine ester (2), together with 11 known compounds. Isolated bufadienolides showed significant inhibition effect against human hepatocellular carcinoma cell line SMMC-7721 in vitro.

Keywords:

• Bufo bufo gargarizans
• toad skin
• N-[2-hydroxy-2-(4-hydroxyphenyl)ethyl]-N-methylurea
• 19-oxocinobufotalin 3-adipoylarginine ester
• cytotoxicity

Acknowledgements

The project was supported by the Natural Science Foundation of Fujian Province of China (No. 2010J05087). The authors gratefully acknowledge Li Shen, Center of Analysis and Test, School of Pharmacy, Yantai University, for her kind help in determination of their samples.