Molluscicidal steroid glycoalkaloids possessing stereoisomeric spirosolane structures.

Both the steroidal glycoalkaloid mixture obtained from Solanum mammosum fruits (solasonine 1 and solamargine 2) and the stereoisomeric glycosidic alkaloid tomatine 3 are toxic at 10 and 25 ppm to Lymnaea cubensis and Biomphalaria glabratus, respectively. Their aglycones solasodine 4 and tomatidine 5 obtained by hydrolysis of the glycosides showed no toxicity to either mollusk under the test conditions used. Preliminary structure-activity correlations indicate that the molluscicidal properties depend on the type of aglycones and on the glycoside bond. A common molecular structure in molluscicidal spirosolane and spirostane glycosides is recognized.