Fungal Endophytes: A Potential Source of Antibacterial Compounds

Abstract

Antibiotic resistance is becoming a burning issue due to the frequent use of antibiotics for curing common bacterial infections, indicating that we are running out of effective antibiotics. This has been more obvious during recent corona pandemics. Similarly, enhancement of antimicrobial resistance (AMR) is strengthening the pathogenicity and virulence of infectious microbes. Endophytes have shown expression of various new many bioactive compounds with significant biological activities. Specifically, in endophytic fungi, bioactive metabolites with unique skeletons have been identified which could be helpful in the prevention of increasing antimicrobial resistance. The major classes of metabolites reported include anthraquinone, sesquiterpenoid, chromone, xanthone, phenols, quinones, quinolone, piperazine, coumarins and cyclic peptides. In the present review, we reported 451 bioactive metabolites isolated from various groups of endophytic fungi from January 2015 to April 2021 along with their antibacterial profiling, chemical structures and mode of action. In addition, we also discussed various methods including epigenetic modifications, co-culture, and OSMAC to induce silent gene clusters for the production of noble bioactive compounds in endophytic fungi.

Keywords: AMR; antibacterial compound; drug resistance; endophytic fungi; medicinal plant; natural product.

Figure 1

Structures of metabolites 1–22 isolated from Ascomycetes.

Figure 2

Structures of metabolites 23–37 isolated from Ascomycetes.

Figure 3

Structures of metabolites 38–55 isolated from Ascomycetes.

Figure 4

Structures of metabolites 56–70 isolated from Ascomycetes.

Figure 5

Structures of metabolites 71–82 isolated from Ascomycetes.

Figure 6

Structures of metabolites 83–102 isolated from Ascomycetes.

Figure 7

Structures of metabolites 103–126 isolated from Ascomycetes.

Figure 8

Structures of metabolites 127–144 isolated from Ascomycetes.

Figure 9

Structures of metabolites 145–158 and 159–162 isolated from Ascomycetes and Anamorphic Ascomycetes, respectively.

Figure 10

Structures of metabolites 163–178 isolated from Anamorphic Ascomycetes.

Figure 11

Structures of metabolites 179–201 isolated from Anamorphic Ascomycetes.

Figure 12

Structures of metabolites 202–220 isolated from Anamorphic Ascomycetes.

Figure 13

Structures of metabolites 221–242 isolated from Anamorphic Ascomycetes.

Figure 14

Structures of metabolites 243–261 isolated from Anamorphic Ascomycetes.

Figure 15

Structures of metabolites 262–284 isolated from Anamorphic Ascomycetes.

Figure 16

Structures of metabolites 285–299 isolated from Anamorphic Ascomycetes.

Figure 17

Structures of metabolites 300–323 isolated from Anamorphic Ascomycetes.

Figure 18

Structures of metabolites 324–342 isolated from Anamorphic Ascomycetes.

Figure 19

Structures of metabolites 343–356 isolated from Anamorphic Ascomycetes.

Figure 20

Structures of metabolites 357–374 isolated from Anamorphic Ascomycetes.

Figure 21

Structures of metabolites 375–378 isolated from Anamorphic Ascomycetes and 379–394 from Minor Anamorphic Ascomycetes.

Figure 22

Structures of metabolites 395–415 isolated from Minor Anamorphic Ascomycetes.

Figure 23

Structures of metabolites 416–435 isolated from Minor Anamorphic Ascomycetes.

Figure 24

Structures of metabolites 436–443 isolated from Minor Anamorphic Ascomycetes, 444–450 from Basidiomycetes and 451 from Zygomycetes.