Isolation and structures of erylosides from the Caribbean sponge Erylus formosus

Nine new triterpene glycosides, erylosides F1-F4 (1-4), M (5), N (6), O (7), P (8), and Q (9), along with previously known erylosides F (10) and H (11) were isolated from the sponge Erylus formosus collected from the Mexican Gulf (Puerto Morelos, Mexico). Structures of 1-4 were determined as the corresponding biosides having aglycons related to penasterol with additional oxidation patterns in their side chains. Erylosides 5-9 contain new variants of carbohydrate chains with three (5, 6), four (7), and six (8, 9) sugar units, respectively. Erylosides 5, 7, 8, and 6, 9 contain 14-carboxy-24-methylenelanost-8(9)-en-3beta-ol and penasterol as aglycons, respectively. In contrast with its epimer 2, the compound 3 induced the early apoptosis of Ehrlich carcinoma cells at a concentration of 100 microg/mL, while 1 and 10 activated the Ca2+ influx into mouse spleenocytes (130% of the control) at the same doses.