The glycoterpenoid syphonoside (1) is the main secondary metabolite of both the marine mollusk Syphonota
geographica and the sea-grass Halophila stipulacea, two Indo-Pacific species migrated to the Mediterranean
Sea through the Suez Canal. The structure and the absolute stereochemistry of 1, which displays unique
structural features, has been accomplished by using a combination of spectroscopic techniques, degradation
reactions, and conformational analysis methods. Compound 1 was able to inhibit high density induced
apoptosis in a number of human and murine carcinoma cell lines