Among some twenty bufadienolides hitherto known, thirteen of them were isolated from the Chinese toad venom drug, Ch'an Su. We have recently described on the detection of unknown compounds with the isolation and characterization of them. The chloroform extract of Ch'an Su afforded a mixture of unknown materials by column chromatography on silica gel which was eluted by adopting the dry method using an n-hexane acetone mixture. By rechromatography of the mixture, there were obtained six bufadienolides, one of which was identified to be marinobufagin V, first isolation from Ch'an Su. The second compound, mp. 210-212°, was named resibufagin. This new bufadienolide was assigned the structure I (3β-hydroxy-19-oxo-14,15β-epoxy-5β-bufa-20,22-dienolide). The other four compounds was characterizated to be Bufogenin 3-hemisuberates. So, this new bufogenin esters have been elucidated to be cinobufagin 3-hemisuberate(IX), resibufogenin 3-hemisuberate(XII), bufalin 3-hemisuberate (XV) and gamabufotalin 3-hemisuberate(XVII)respectively. Our results, which demonstrated the occurrence of 3-(hydrogen suberoyl)-bufogenins, might be extended to the so-called "bufotoxins" to have suberoyl-arginine grouping at 3-position.
