Cytotoxic Cembranes from Indonesian Specimens of the Soft Coral Nephthea sp.

Hedi Indra Januar,Cherie A Motti,Dianne M Tapiolas,Ekowati Chasanah,Catherine H Liptrot,Anthony D Wright

doi:10.3390/md8072142

Abstract

Methanol extracts of two specimens of the soft coral Nephthea sp. collected from the Seribu Islands, Indonesia, were active in an anticancer bioassay. One new (1) and four known diterpenes (2–5) based on the cembrane carbon skeleton were isolated from these extracts, as was arachidonic acid (8). The structures of all compounds were elucidated using NMR, including 1,1-ADEQUATE and 1D gradient selective NOESY where applicable to determine the relative stereochemistry. Spectroscopic data, including 1H and 13C NMR, UV, IR and optical rotations are reported when enough material was available and where this has not been done previously. Inhibition assays employing three cancer cell lines; SF-268 (CNS), MCF-7 (breast), and H460 (lung) were used to guide the isolation of all compounds.

Highlights

A large diversity of marine organisms have been shown to produce secondary metabolites as a means of defense [1,2,3,4], many of these compounds possess interesting biological activities [5,6,7].Soft corals are no exception [8,9,10,11,12]
Investigations of soft corals from Indonesian waters have been limited with only six such reports on six unrelated soft coral species [13,14,15,16,17,18], the first of these appearing in 1997 [13]
Since 2002 [15,16], aside from the research undertaken by Fattorusso et al [17], Wang et al [18], and the current authors [19,20,21,22], there is little work being done with soft corals from this region of the world, even though they are likely to be rich sources of biologically active secondary metabolites

Summary

Introduction

A large diversity of marine organisms have been shown to produce secondary metabolites as a means of defense [1,2,3,4], many of these compounds possess interesting biological activities [5,6,7]. Since 2002 [15,16], aside from the research undertaken by Fattorusso et al [17], Wang et al [18], and the current authors [19,20,21,22], there is little work being done with soft corals from this region of the world, even though they are likely to be rich sources of biologically active secondary metabolites. This report describes the structural elucidation of (1) and clearly shows that soft corals of Indonesian origin have significant potential as sources of biologically active and drug development lead compounds

Results and Discussion

General experimental

Animal material

Bioassay

Extraction and isolation