Reiko Ueoka

Isolation of azaspiracid-2 from a marine sponge Echinoclathria sp. as a potent cytotoxin

Azaspiracid-2 was isolated from a marine sponge Echinoclathria sp. collected off Amami-Oshima as the predominant cytotoxic constituent. A combination of HPLC using ODS, GS320, and Phenylhexyl stationary phases permitted the purification without using acid or inorganic additives in the mobile phase. Azaspiracid-2 exhibited potent cytotoxicity against P388 cells with an IC50 value of 0.72 ng/mL and caused S phase arrest on the cell cycle.

Gracilioethers A-C, antimalarial metabolites from the marine sponge Agelas gracilis

Three new antiprotozoan compounds, gracilioethers A-C (1-3), have been isolated from the marine sponge Agelas gracilis. Their structures were elucidated on the basis of spectroscopic and chemical methods. Gracilioethers A-C showed antimalarial activity against Plasmodium falciparum with IC(50) values of 0.5-10 microg/mL, whereas gracilioether B (2) also showed antileishmanial activity.

Isolation of spirastrellolides A and B from a marine sponge Epipolasis sp. and their cytotoxic activities.

Spirastrellolides A (1) and B (3) have been isolated as free acids from a marine sponge Epipolasis sp. collected in the East China Sea. These compounds had been isolated from the Caribbean marine sponge Spirastrella coccinea after conversion to the methyl ester. We examined the cytotoxic activities of 1 and 3 and found that the activities of the free acids are comparable to those of the corresponding methyl esters.

Aplysinoplides A-C, cytotoxic sesterterpenes from the marine sponge Aplysinopsis digitata.

Three sesterterpenoids, aplysinoplides A-C (1- 3), were isolated from the marine sponge Aplysinopsis digitata. Their structures were determined on the basis of spectroscopic data. They exhibited cytotoxic activity against P388 mouse leukemia cells.

Ceratodictyols, 1-glyceryl ethers from the red alga-sponge association Ceratodictyon spongiosum/Haliclona cymaeformis.

Six 1-glyceryl ethers (1-6) were isolated from the red alga-sponge assemblage Ceratodictyon spongiosum/Haliclona cymaeformis. Structural assignments were conducted by interpretation of spectroscopic data and the modified Moshers method. Four allylic alcohols were obtained as a pair of epimeric mixtures (3/4 and 5/6). These glyceryl ethers exhibited weak cytotoxic activity against HeLa human cervical cancer cells.

Ophiodilactones A and B, cytotoxic tetrameric phenylpropanoids, from the ophiuroid Ophiocoma scolopendrina.

Two tetrameric phenylpropanoids, ophiodilactones A (1) and B (2), were isolated from the ophiuroid Ophiocoma scolopendrina. Their structures were determined on the basis of spectroscopic data. Ophiodilactone B has a novel carbon skeleton. They exhibit moderate cytotoxic activity against P388 murine leukemia cells.

Inconspicamide, New N-Acylated Serinol from the Marine Sponge Stelletta inconspicua

A new N-acylated serinol, inconspicamide (1), was isolated from the marine sponge, Stelletta inconspicua, together with a glyceryl ether (2). Their structures were determined on the basis of spectroscopic data and the modified Mosher analysis. They exhibited moderate cytotoxic activity against HeLa human cervical cancer cells.