Cyclitol Derivatives from the Sponge Sarcotragus Species

Marine sponges of the order Dictyoceratida are known to contain various furanosesterterpene derivatives that possess interesting biological properties.1 Dozens of new furanoand pyrroloterpenoids have been isolated from Sarcotragus sp.(Dictyoceratida) collected from Korean waters.2,3In our continuing study on the cytotoxic compounds of Sarcotragus sp., the cyclitol derivative sarcotride A (1) has been isolated along with two new congeners (2 and 3).The gross structures of the compounds were elucidated by the aid of COSY, HMQC, and HMBC experiments.The isolation, structure elucidation, and biological activity of the compounds are described herein.The methanol extract of the sponge displayed cytotoxi cities against five human tumor cell lines (see Experimental Section) and showed toxicity to brine shrimp larvae (LD50, 93 "g/mL).Guided by the brine shrimp assay, the methanol extract was successively fractionated employing reversedphase flash column chromatography and ODS HPLC to afford compounds 1-3 as the active components.Sarcotride A (1) was isolated as a light yellow oil.The molecular formula of 1 was established as C25H50O7 on the basis of HRFABMS.The [M+N이+ ion was observed at m/z 485.3436 (CzsRoOzNa, A -1.8 mmu).The NMR data of 1 was identical to those reported for the cyclitol derivative from the Korean marine sponge Petrosia sp.4The location of the methyl branching in 1 was clearly recognized from the FAB-CID tandem mass spectrum of the [M+N이+ ion.