Anthraquinones and Derivatives from Marine-Derived Fungi: Structural Diversity and Selected Biological Activities

Abstract

Anthraquinones and their derivatives constitute a large group of quinoid compounds with about 700 molecules described. They are widespread in fungi and their chemical diversity and biological activities recently attracted attention of industries in such fields as pharmaceuticals, clothes dyeing, and food colorants. Their positive and/or negative effect(s) due to the 9,10-anthracenedione structure and its substituents are still not clearly understood and their potential roles or effects on human health are today strongly discussed among scientists. As marine microorganisms recently appeared as producers of an astonishing variety of structurally unique secondary metabolites, they may represent a promising resource for identifying new candidates for therapeutic drugs or daily additives. Within this review, we investigate the present knowledge about the anthraquinones and derivatives listed to date from marine-derived filamentous fungi's productions. This overview highlights the molecules which have been identified in microorganisms for the first time. The structures and colors of the anthraquinoid compounds come along with the known roles of some molecules in the life of the organisms. Some specific biological activities are also described. This may help to open doors towards innovative natural substances.

Keywords: anthraquinone; antibiotic; antitumor; biological activity; cytotoxicity; fungi; marine; pigment.

Figure 1

Anthraquinone general structure (R1–R8: lateral substituents).

Figure 2

Marine habitats hosting fungal anthraquinones producers. (a) Tree and marine plants growing in a submerged area (b) Aplysina aerophoba (mediterranean sponge), usual host of endophytic filamentous fungi; (c) Aspergillus versicolor, exhibiting a pink pigment.

Figure 3

Anthraquinones biosynthetic pathway in fungi. (a) Regioselectivity in the formation of the β-polyketide chain during the synthesis of antraquinones in fungi (adapted from Gessler et al. [17]). ACP: Acyl Carrier Protein; (b) Anthraquinones acetate-malonate pathway in fungi: synthesis of emodin type pigments (from Caro et al. [16]).