New triterpenoids from the Red Sea sponge Siphonochalina siphonella.

ABSTRACT

Clear differences were found when comparing the chemical content of the northern, Gulf of Eilat, to the southern-central, Dahlak archipelago, Red Sea sponge Siphonochalina siphonella. The Dahlak sponge was found to be richer in the more polar triterpenes. Nine new compounds (1-4, 7, 8, 15-17) were isolated and identified, among them two sipholane glycosides, sipholenoside A and B (7 and 8), and one compound, dahabinone A (17), possessing a new skeleton.