Bufadienolides from the Eggs of the Toad Bufo bufo gargarizans and Their Antimelanoma Activities

J Nat Prod. 2021 May 28;84(5):1425-1433. doi: 10.1021/acs.jnatprod.0c00840. Epub 2021 Apr 21.

Abstract

Toads produce potent toxins, named bufadienolides, to defend against their predators. Pharmacological research has revealed that bufadienolides are potential anticancer drugs. In this research, we reported nine bufadienolides from the eggs of the toad Bufo bufo gargarizans, including two new compounds (1 and 3). The chemical structures of 1 and 3, as well as of one previously reported semisynthesized compound (2), were elucidated on the basis of extensive spectroscopic data interpretation, chemical methods, and X-ray diffraction analysis. Compound 1 is an unusual 19-norbufadienolide with rearranged A/B rings. A biological test revealed that compounds 2 and 4-8 showed potent cytotoxic activities toward human melanoma cell line SK-MEL-1 with IC50 values less than 1.0 μM. A preliminary mechanism investigation revealed that the most potent compound, 8, could induce apoptosis via PARP cleavage, while 5 and 6 significantly suppressed angiogenesis in zebrafish. Furthermore, an in vivo biological study showed that 5, 6, and 8 inhibit SK-MEL-1 cell growth significantly.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Animals
  • Antineoplastic Agents / pharmacology*
  • Apoptosis / drug effects
  • Bufo bufo*
  • Cell Line, Tumor
  • Humans
  • Melanoma / drug therapy*
  • Molecular Structure
  • Ovum / chemistry*
  • Zebrafish

Substances

  • Antineoplastic Agents