Resibufagin shows strong cytotoxic activity against HeLa cell line.

A new bufadienolide named 16beta-acetoxy-bufarenogin (1), together with six known bufadienolides, namely, 11alpha,12beta-dihydroxy-bufalin (2), bufotalin (3), hellebrigenin (4), desacetylbufotalin (5), gamabufotalin (6), and Resibufagin (7) were isolated from Chan'Su. Of these, 2 was a new natural product. Their structures were elucidated by spectral methods.