Chemical constituents of bufadienolides in cinobufacino injection

Cinobufacino injection is purified from water extraction of the skin of Bufo bufo gargarizans, which has been widely used for various cancers in clinic with significant anti-tumor effects. Bufadienolides were regarded as the main active constituents of cinobufacino injection in previous reports. In present study, 6 bufadienolides were isolated and purified from Cinobufacino injection. Their structures were identified as 3-epi-ψ-bufarenogin(1), ψ-bufarenogin(2), 3-epi-arenobufagin(3), arenobufagin(4), 3-epi-gamabufotalin(5), and 3-oxo-arenobufagin(6), separately. Among them, 1 and 3 were new compounds, 5 and 6 were new natural products. Compounds 1, 2 and compounds 3, 4 were two pairs configuration isomers at C-3, separately.