Natural polyketide 6-pentyl-2<i>H</i>-pyrone-2-one and its synthetic analogues efficiently prevent marine biofouling

Abstract

Biofouling is a widespread phenomenon in oceans worldwide. With increasing human development and activities in open and coastal waters, and due to the environmental impact of AF organotins and copper-based paint, the demand for nontoxic antifouling (AF) paints is increasing. Various bioassays for antimicrobial activity, anti-biofilm formation and anti-barnacle settlement were established to evaluate the possibility of using marine natural products as AF agents. A series of natural products, isolated from the marine-derived fungi <i>Trichoderma atroviride</i> and <i>T. reesei</i>, were evaluated for their AF activity. One pyrone-type compound (<b>1</b>) demonstrated significant inhibitory activities toward barnacle cyprid settlement. Furthermore, a series of pyrone analogues (<b>S1</b>-<b>S6</b>) were synthesized, and their bioactivities were evaluated in the established systems. The results showed that compounds <b>S5</b> and <b>S6</b> exhibited a broad spectrum of bioactivities, such as anti-barnacle settlement, anti-biofilm formation and antimicrobial activities.