Fungal perylenequinones

Abstract

Perylenequinones (PQs) are aromatic polyketides with an oxidized pentacyclic core that make up a family of natural compounds. Naturally occurring PQs mostly are produced by phytopathogenic fungi, with few aphides, crinoids, and plants. PQs, also known as photosensitizers, absorb light energy which empowers them to produce reactive oxygen species that damage host cells. Therefore, PQs gained a considerable interest in pharmaceutical application notably in photodynamic therapy. This review presents a comprehensive overview of fungal PQs. Their occurrence, categorization, biosynthesis, structures, and bioactivities are all discussed in detail. After that, an analysis outlines their distribution across the kingdom of fungi. A total of 66 fungal PQs have been described from 22 ascomycete genera (Alternaria, Aspergillus, Bulgaria, Cenococcum, Cercospora, Cladosporium, Curvularia, Daldinia, Elsinoë, Hypocrella, Hypomyces, Parastagonospora, Phaeosphaeria, Phylacia, Pyrenochaeta, Rhopalostroma, Rubroshiraia, Setophoma, Shiraia, Stemphylium, Stagonospora, and Thamnomyces). Dothideomycetes account for the majority of documented fungal PQs (82%), followed by Sordariomycetes (14%), Leotiomycetes (3%), and Eurotiomycetes (1%). Herein, five families Pleosporaceae, Phaeosphaeriaceae, Cladosporiaceae, Shiraiaceae, and Hypoxylaceae are highlighted as potential sources of novel PQs due to their diversity. The review intends to pique bioprospectors' interest in fungal PQs. Indeed, the pharmaceutical and agrochemical industries might gain greatly by exploiting fungal perylenequinones. Graphical abstract.

Keywords: Dothideomycetes; Fungal natural products; Perylenequinones; Photodynamic therapy; Sordariomycetes.

Graphical abstract

Fig. 1

Classification of perylenequinones

Fig. 2

Axial chirality P and M of perylenequinones

Fig. 3

The biosynthetic gene clusters of cercosporin CTB, elsinochrome A (45) elc, and hypocrellin A (50) HYP. Modified from Chooi et al. (2017) and Hu et al. (2019)

Fig. 4

Proposed biosynthetic pathway for three perylenequinones of class B: cercosporin (30), elsinochrome A (45), and hypocrellin (50). Modified from Hu et al. (2019)

Fig. 5

Perylenequinones described from the genera Alternaria and Setophoma

Fig. 6

Reported perylenequinones from the genera Alternaria, Aspergillus, Bulgaria, Cenococcum, Curvularia, Daldinia, Phylacia, Rhopalostroma, Setophoma, Stemphylium, and Thamnomyces

Fig. 7

Reported perylenequinones from the genera Cercospora and Cladosporium

Fig. 8

Produced perylenequinones by the genera Elsinoë, Hypocrella, Hypomyces, Parastagonospora, Pyrenochaeta, and Stagonospora

Fig. 9

Described perylenequinones from the genera Phaeosphaeria and Shiraia

Fig. 10

Number of fungal PQs per genus

Fig. 11

Distribution of PQs among fungal classes

Fig. 12

Outline of PQ-producing fungi