Isolation of C11 Compounds and a Cyclopropane Fatty Acid from an Okinawan Ascidian, Diplosoma sp.

Tamanna Rob,Wilmar Maarisit,Katsuhiro Ueda,Takayuki Ogi,Junsei Taira

doi:10.3390/molecules16129972

Abstract

Pentylphenols 1 and 2, cyclopropane fatty acid 3, and cyclopentenones 4 and 5, were isolated from an ascidian, Diplosoma sp. The structures of 1−5 were determined by spectroscopic analysis and/or synthesis. Compound 1 inhibited the division of fertilized sea urchin eggs and compound 4 showed mild cytotoxity against HCT116 cells (human colorectal cancer cell).

Highlights

Ascidians are a rich source of novel bioactive secondary metabolites, including a diverse array of amino acid-derived alkaloids, cyclic peptides, and acetogenins [1,2,3,4]
As part of our ongoing research aimed at the isolation of biologically active metabolites from marine organisms living in the tidal zone, we have isolated fourteen C11 compounds, dinemnenone congeners 6–18 and 22 from the didemnid ascidians
As part of our continuing chemical studies of Okinawan marine organisms, we examined the constituents of the ascidian Diplosoma sp

Summary

Introduction

Ascidians are a rich source of novel bioactive secondary metabolites, including a diverse array of amino acid-derived alkaloids, cyclic peptides, and acetogenins [1,2,3,4]. A series of C11 compounds having the distinctive exo-allylidene-lactone named didemnenones were isolated from didemnid ascidians, Trididemnum cyanophorum [didemnenones A (6) and B (7)] and Didemnum voeltzkowi (didemnenones C and D) [5]. They showed a wide range of biological activities, including toxicity against leukemia cells as well as antimicrobial and antifungal activities. As part of our ongoing research aimed at the isolation of biologically active metabolites from marine organisms living in the tidal zone, we have isolated fourteen C11 compounds, dinemnenone congeners 6–18 and 22 from the didemnid ascidians. Rapid fractionation of the extract made from a second collection in April 2006 gave new unstable C11 compounds 4 [12] and 5

Results and Discussion

General Experimental Procedures

Animal Material

Extraction and Isolation

Conclusions