New Cytotoxic Sesterterpenes from the Sponge Sarcotragus Species

Abstract

Five new (1-3, 5, and 7) and two known (4, 6) furanosesterterpene tetronic acids were isolated from the marine sponge Sarcotragus sp. by bioactivity-guided fractionation. These compounds showed cytotoxicity against a panel of five human tumor cell lines. The gross structures were established on the basis of NMR and MS analyses. The compounds showed interesting variations of geometry and absolute configuration.

Variabilin, a Chemotaxonomic Marker for the Family Irciniidae

“…Examination of the 13 C NMR chemical shifts for the vinylic methyl resonance confirmed the geometry of the trisubstituted double bonds as 7E,12E and 20Z. The assignments of the carbon atoms and protons were supported by COSY and HMBC experiments and were similar to the literature values of the geometric isomer (7E,12E,20Z)-variabilin (Liu et al, 2001(Liu et al, , 2002a(Liu et al, , 2003Choi et al, 2004).…”

“…Por. 33) was deposited in the Natural History Museum, Hannam University, and has been described elsewhere (Liu et al, 2001).…”

“…The CH 2 Cl 2 layer was further partitioned between 90% methanol and n-hexane to yield 90% methanol-(54 g) and n-hexane-soluble (13 g) fractions. As described in our previous report (Liu et al, 2001), the 90% methanol fraction was subjected to reversed-phase flash column chromatography using a YMC Gel ODS-A column (60 Å , 500/400 mesh), eluted with the solvent system 25 to 0% H 2 O/ MeOH, to afford 20 fractions (Fg1ÐFg20). These fractions were evaluated for activity in the brine shrimp assay, and fractions Fg6ÐFg9 were found active.…”

“…Sponges of the genus Sarcotragus were reported to contain compounds such as variabilin (Perry et al, 1987), (7E,12E,20E)-variabilin, (7E,12Z,20Z)-variabilin, 8-hydroxy-(12E,20Z)-variabilin, 14-furan-3-yl-3,7,11-trimethyl-tetradeca-7,11-dienoic acid (Barrow et al, 1988), sarcochromenol sulfates AÐC and sarcohydroquinone sulfates AÐC (Stonik et al, 1992), octa-and nonaprenylhydroquinone sulfates (Wakimoto et al, 1999), geranylfarnesylacetone (Ponomarenko et al, 1998), and sarcotragins A and B (Shin et al, 2001). In our previous studies on the cytotoxic compounds of two sponges of the genus Sarcotragus, thirty-three cytotoxic terpenoids, three cyclitols, a trisoxazole macrolide, three indole alkaloids, three glycerolipids, and a fatty acid ester were reported (Liu et al, 2001(Liu et al, , 2002a(Liu et al, , b, 2003(Liu et al, , 2005(Liu et al, , 2006b.…”

Heterocyclic terpenes: linear furano- and pyrroloterpenoids

“…183 An efficient and stereodefined process is employed, featuring lipase-catalyzed asymmetric desymmetrization of two types of propanediol precursors incorporating the terpene skeleton. Eight cytotoxic furanosesterterpenoids, namely ircinins 1and 2, sacotins D 260 and E 261, 166 sacotins G 262 and H 263, 125 (7E,12E,18R,20Z)-variabilin, and (8E,13Z,18R,20Z)-strobilinin, 138 were reported from a specimen of Sarcotragus sp. collected off Cheju Island, Korea.…”