Flavonoid Glycosides with a Triazole Moiety for Marine Antifouling Applications: Synthesis and Biological Activity Evaluation.

Vitor Vasconcelos,Madalena Pinto,Joana R Almeida,Marta Correia-Da-Silva,Honorina Cidade,Andreia Palmeira,Beatriz T Martins,Catarina Gonçalves,Daniela Pereira

doi:10.3390/md19010005

Abstract

Over the last decades, antifouling coatings containing biocidal compounds as active ingredients were used to prevent biofouling, and eco-friendly alternatives are needed. Previous research from our group showed that polymethoxylated chalcones and glycosylated flavones obtained by synthesis displayed antifouling activity with low toxicity. In this work, ten new polymethoxylated flavones and chalcones were synthesized for the first time, including eight with a triazole moiety. Eight known flavones and chalcones were also synthesized and tested in order to construct a quantitative structure-activity relationship (QSAR) model for these compounds. Three different antifouling profiles were found: three compounds (1b, 11a and 11b) exhibited anti-settlement activity against a macrofouling species (Mytilus galloprovincialis), two compounds (6a and 6b) exhibited inhibitory activity against the biofilm-forming marine bacteria Roseobacter litoralis and one compound (7b) exhibited activity against both mussel larvae and microalgae Navicula sp. Hydrogen bonding acceptor ability of the molecule was the most significant descriptor contributing positively to the mussel larvae anti-settlement activity and, in fact, the triazolyl glycosylated chalcone 7b was the most potent compound against this species. The most promising compounds were not toxic to Artemia salina, highlighting the importance of pursuing the development of new synthetic antifouling agents as an ecofriendly and sustainable alternative for the marine industry.

Highlights

Introduction in published maps and institutionalMarine biofouling, resulting from the accumulation of marine micro and macroorganisms on submerged surfaces, has been a huge problem for maritime industries, causing several technical and economic problems, including corrosion of materials and the increase in fuel consumption
Instead of a microwave (MW) irradiation, the synthesis of flavones 1a and 1b was performed in a muffle furnace
ΜM.,the theinhibition inhibition of this enzyme, with a crucial effect in the formation of mussel adhesive, could be one of the mechanisms involved in the inhibition of the mussel settlement. This highlights a specific AF mode of action related with mussel adhesion and explains the absence of activity against bacteria and diatoms

Summary

Introduction

Introduction in published maps and institutionalMarine biofouling, resulting from the accumulation of marine micro and macroorganisms on submerged surfaces, has been a huge problem for maritime industries, causing several technical and economic problems, including corrosion of materials and the increase in fuel consumption. Marine biofouling is associated with environmental and health problems, due to an increase in gas emissions and the spread of invasive species [1,2]. Biocidal paints containing organotin compounds, namely tributyltin (TBT), were widely used for decades in the maritime industry to prevent biofouling. Due to their negative effect on the environment and on live organisms, these substances were completely banned in 2008 by the international maritime organization [3]. Some booster biocides, such as Irgarol 1051 or Sea-nine 211, in combination with copper, have been used; even these compounds have demonstrated toxicity on living organisms. Several non-toxic marine natural products with AF activity have been reported; among them, some flavonoids presented potential AF activity and low toxicity, suggesting their potential as new lead compounds for the development of new AF agents [7]

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Results

Conclusion