Evaluation of the Activity of the Sponge Metabolites Avarol and Avarone and their Synthetic Derivatives Against Fouling Micro- and Macroorganisms

Maria Tsoukatou,Jean Philippe Maréchal,Anthony S Clare,Irena Novaković,Constantinos Vagias,Dusan Sladić,Vassilios Roussis,Miroslav J Gašić,Claire Hellio,Srdan Tufegdzic

doi:10.3390/12051022

Abstract

The sesquiterpene hydroquinone avarol (1) was isolated from the marine sponge Dysidea avara, whereas the corresponding quinone, avarone (2), was obtained by oxidation of avarol, and the significantly more lipophilic compounds [3'-(p-chloro-phenyl)avarone (3), 3',4'-ethylenedithioavarone (4), 4'-isopropylthioavarone (5), 4'-tert-butylthioavarone (6), 4'-propylthioavarone (7), 4'-octylthioavarone (8)] were obtained by nucleophilic addition of thiols or p-chloroaniline to avarone. All these compounds were tested, at concentrations ranging from 0.5 to 50 microg/mL, for their effect on the settlement of the cyprid stage of Balanus amphitrite, for toxicity to both nauplii and cyprids and for their growth inhibitory activity on marine bacteria (Cobetia marina, Marinobacterium stanieri, Vibrio fischeri and Pseudoalteromonas haloplanktis) and marine fungi (Halosphaeriopsis mediosetigera, Asteromyces cruciatus, Lulworthia uniseptata and Monodictys pelagica).

Highlights

One of the most serious problems that marine technology is currently facing is the control of biofouling on man-made structures [1, 2]
Efficient antifouling paints are based on copper compounds and booster biocides that when submerged, release toxic compounds causing adverse environmental effects [3,4,5,6,7,8]
In continuation of our studies towards the discovery of natural products that are effective against marine biofouling [14, 15], we investigated barnacle settlement inhibition and marine bacterial growth inhibition with the sponge metabolites avarol (1), avarone (2) and the synthetic derivatives 3-8

Summary

Introduction

One of the most serious problems that marine technology is currently facing is the control of biofouling on man-made structures [1, 2]. Efficient antifouling paints are based on copper compounds and booster biocides that when submerged, release toxic compounds causing adverse environmental effects [3,4,5,6,7,8]. There is clearly a need to develop new non-toxic or environmentally benign antifouling alternatives that would be efficient against the most severe fouling organisms such as barnacles, blue mussels, bryozoans and algae [12]. Quinoid moiety are structurally associated, often exhibit pronouced cytotoxicity [17,18,19,20] Another reason that led us to evaluate the barnacle settlement inhibition of D. avara metabolites is that a significant number of other sponge metabolites have exhibited promising activities in an array of antifouling assays [21,22,23,24]

Results and Discussion

2: Avarone

Conclusions