Update of spectroscopic data for 4-hydroxydictyolactone and dictyol E isolated from a Halimeda stuposa - Dictyota sp. assemblage.

Simon P B Ovenden,Catherine H Liptrot,Anthony D Wright,Jonathan L Nielson,Richard H Willis,Cherie A Motti,Dianne M Tapiolas

doi:10.3390/molecules17032929

Simon P B Ovenden, Catherine H Liptrot + Show 5 more

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https://doi.org/10.3390/molecules17032929

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Abstract

The methanol extract of an assemblage of Halimeda stuposa and a Dictyota sp., yielded three natural products characteristic of Dictyota sp., and one of Halimeda sp. These included the xenicane diterpene 4-hydroxydictyolactone (1), and the diterpenes dictyol E (2), 8α,11-dihydroxypachydictyol A (3) and indole-3-carboxaldehyde (4). A minor revision of 1 and new spectroscopic data for 1 and 2 are provided, along with associated anti-cancer activities of compounds 1–4.

Highlights

[14] The methanol (MeOH) extract of a large scale recollection was subjected to bioassay-guided fractionation, using C18 flash vacuum liquid chromatography and preparative C18 HPLC, to yield the xenicane lactone 4-hydroxydictyolactone (1) [15], as well as the known diterpenes dictyol E (2) [16], 8,11-dihydroxypachydictyol A (3) [17], and indole-3-carboxaldehyde (4) [18] (Figure 1)
Described below are a minor revision of 1, as well as CD data and molecular modelling studies, in accordance with the absolute configuration previously reported [19], and NMR evidence confirming the presence of the minor cis conformer of 1 [20]
There are many reports on the isolation of xenicane diterpenes from algae of the genera Dictyota sp. [12,29,30,31,32,33,34], Pachydictyon sp. [35,36,37], Glossophora sp. [38] and Dilophus sp. [15,16,39], with the latter three genera recognized as Dictyota species [40], and of pachydictyane diterpenes from algae of the genera Dictyota sp. [41], Sargassum sp. [42], Glossophora sp. [26] and Cystoseira sp. [43], there are very few that discuss their cytotoxic properties

Summary

Introduction

There have been many reports involving chemical investigations of algae from the genera Halimeda [1,2,3,4] and Dictyota [5,6,7,8,9,10], with Dictyota species in particular being a prolific source of novel terpenoids. Considering the well documented history of terpenoid chemistry having significant biological activity [11,12,13], this genus of alga is an attractive target for the discovery of novel bioactive metabolites. Presented are the complete 1H-NMR data for 2, as well as the biological activities of 1–4 against a panel of human tumour and normal mammalian cell lines

Results and Discussion

Plant Material

Extraction and Isolation

Conclusions

25. ChemBio3D