SIMILARITY AND DIS-SIMILARITY OF BUFAGINS, BUFOTOXINS, AND DIGITALOID GLUCOSIDES

In previous communications (1-12), we have presented data, both chemical and pharmacological, on the active principles isolated from Ch’an Su and the “parotid ” secretion of each of 12 different species of toads. Generally speaking, there is a resemblance in the results from one species to another, but there are certain differences that can be detected by scrupulous exam-ination of the detailed records. We have already indicated in our preliminary reports (13, 14) that the respective bufagins, bufo-toxins, and bufotenines are not all identical with one another. The present paper deals with the strict comparison of bufagins, bufotoxins, and a few members of the digitalis series, and it con-stitutes a r#{233}sum#{233}of our findings concerning both animal and plant products which have a specific action on the heart. It may be repeated here that the terms bufagins and bufotoxins are employed generically. For each specific principle is prefixed the name of the species, or some reference to the place where the toad is found. The glucosides that were selected as representatives of the digi-talis series consisted of digitoxin, G-strophanthin or ouabain, scillarens A and B, and thevetin-the last being one of the gluco-sides recently isolated by ourselves from the be-still nuts or, botani-cally, Thevetia neriifolia (15). Both scillarens A and B were generously supplied by Professor R. L. Stehle of McGill Univer-sity, Montreal, to whom we feel deeply indebted. Digitoxin and G-strophanthin, both crystalline, were obtained from commercial sources. EVIDENCE OF SIMILARITY 1. Solubility. All the respective bufagins and bufotoxins have approximately the same solubility. Pure bufagins are soluble in 561 at